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Sample records for finger joint angle

  1. Neural network committees for finger joint angle estimation from surface EMG signals

    PubMed Central

    Shrirao, Nikhil A; Reddy, Narender P; Kosuri, Durga R

    2009-01-01

    Background In virtual reality (VR) systems, the user's finger and hand positions are sensed and used to control the virtual environments. Direct biocontrol of VR environments using surface electromyography (SEMG) signals may be more synergistic and unconstraining to the user. The purpose of the present investigation was to develop a technique to predict the finger joint angle from the surface EMG measurements of the extensor muscle using neural network models. Methodology SEMG together with the actual joint angle measurements were obtained while the subject was performing flexion-extension rotation of the index finger at three speeds. Several neural networks were trained to predict the joint angle from the parameters extracted from the SEMG signals. The best networks were selected to form six committees. The neural network committees were evaluated using data from new subjects. Results There was hysteresis in the measured SMEG signals during the flexion-extension cycle. However, neural network committees were able to predict the joint angle with reasonable accuracy. RMS errors ranged from 0.085 ± 0.036 for fast speed finger-extension to 0.147 ± 0.026 for slow speed finger extension, and from 0.098 ± 0.023 for the fast speed finger flexion to 0.163 ± 0.054 for slow speed finger flexion. Conclusion Although hysteresis was observed in the measured SEMG signals, the committees of neural networks were able to predict the finger joint angle from SEMG signals. PMID:19154615

  2. Low-Friction Joint for Robot Fingers

    NASA Technical Reports Server (NTRS)

    Ruoff, C. F.

    1985-01-01

    Mechanical linkage allows adjacent parts to move relative to each other with low friction and with no chatter, slipping, or backlash. Low-friction joint of two surfaces in rolling contact, held in alinement by taut flexible bands. No sliding friction or "stick-slip" motion: Only rolling-contact and bending friction within bands. Proposed linkage intended for finger joints in mechanical hands for robots and manipulators.

  3. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Finger joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained prosthesis is a device...

  4. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Finger joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained prosthesis is a device...

  5. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Finger joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained prosthesis is a device...

  6. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Finger joint polymer constrained prosthesis. 888... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification. A finger joint polymer constrained prosthesis is a device...

  7. 21 CFR 888.3230 - Finger joint polymer constrained prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Finger joint polymer constrained prosthesis. 888.3230 Section 888.3230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3230 Finger joint polymer constrained prosthesis. (a) Identification....

  8. The design and development of a finger joint simulator.

    PubMed

    Joyce, Thomas J

    2016-05-01

    Artificial finger joints lack the long-term clinical success seen with hip and knee prostheses. In part, this can be explained by the challenges of rheumatoid arthritis, a progressive disease which attacks surrounding tissues as well as the joint itself. Therefore, the natural finger joints' biomechanics are adversely affected, and consequently, this imbalance due to subluxing forces further challenges any prosthesis. Many different designs of finger prosthesis have been offered over a period of greater than 50 years. Most of these designs have failed, and it is likely that many of these failures could have been identified had the prostheses been appropriately tested prior to implantation into patients. While finger joint simulators have been designed, arguably only those from a single centre have been able to reproduce clinical-type failures of the finger prostheses tested in them. This article describes the design and development of a finger simulator at Durham University, UK. It explains and justifies the engineering decisions made and thus the evolution of the finger simulator. In vitro results and their linkage to clinical-type failures are outlined to help to show the effectiveness of the simulator. Failures of finger implants in vivo continue to occur, and the need for appropriate in vitro testing of finger prostheses remains strong. PMID:26833697

  9. Simultaneous dislocation of both interphalangeal joints in the middle finger.

    PubMed

    Hester, Thomas; Mahmood, Shoib; Morar, Yateen; Singh, Ravi

    2015-01-01

    Simultaneous dorsal dislocation of both interphalangeal joints (IPJs) in one finger is an uncommon injury. This injury usually occurs on the ulnar side of the hand involving ring and little fingers. We report a case of simultaneous dislocation of both IPJs in the middle finger. Closed reduction and splinting with the IPJs in extension provided a good result with full range of motion at the patient's final follow-up. PMID:25979959

  10. Enhancement of finger motion range with compliant anthropomorphic joint design.

    PubMed

    Çulha, Utku; Iida, Fumiya

    2016-04-01

    Robotic researchers have been greatly inspired by the human hand in the search to design and build adaptive robotic hands. Especially, joints have received a lot of attention upon their role in maintaining the passive compliance that gives the fingers flexibility and extendible motion ranges. Passive compliance, which is the tendency to be employed in motion under the influence of an external force, is the result of the stiffness and the geometrical constraints of the joints that define the direction of the motion. Based on its building elements, human finger joints have multi-directional passive compliance which means that they can move in multiple axis of motion under external force. However, due to their complex anatomy, only simplified biomechanical designs based on physiological analysis are preferred in present day robotics. To imitate the human joints, these designs either use fixed degree of freedom mechanisms which substantially limit the motion axes of compliance, or soft materials that can deform in many directions but hinder the fingers' force exertion capacities. In order to find a solution that lies between these two design approaches, we are using anatomically correct finger bones, elastic ligaments and antagonistic tendons to build anthropomorphic joints with multi-directional passive compliance and strong force exertion capabilities. We use interactions between an index finger and a thumb to show that our joints allow the extension of the range of motion of the fingers up to 245% and gripping size to 63% which can be beneficial for mechanical adaptation in gripping larger objects. PMID:26891473

  11. Dataglove measurement of joint angles in sign language handshapes

    PubMed Central

    Eccarius, Petra; Bour, Rebecca; Scheidt, Robert A.

    2012-01-01

    In sign language research, we understand little about articulatory factors involved in shaping phonemic boundaries or the amount (and articulatory nature) of acceptable phonetic variation between handshapes. To date, there exists no comprehensive analysis of handshape based on the quantitative measurement of joint angles during sign production. The purpose of our work is to develop a methodology for collecting and visualizing quantitative handshape data in an attempt to better understand how handshapes are produced at a phonetic level. In this pursuit, we seek to quantify the flexion and abduction angles of the finger joints using a commercial data glove (CyberGlove; Immersion Inc.). We present calibration procedures used to convert raw glove signals into joint angles. We then implement those procedures and evaluate their ability to accurately predict joint angle. Finally, we provide examples of how our recording techniques might inform current research questions. PMID:23997644

  12. Simultaneous closed dislocation of both interphalangeal joints in one finger.

    PubMed

    Ron, D; Alkalay, D; Torok, G

    1983-01-01

    A rare case of simultaneous dislocation of both interphalangeal joints in one finger in a table-tennis player is presented. The second dislocation took place when the first dislocated joint became the fixed part of the finger as it hit a wall. Treatment was, first, hyperextension to unlock the base of the phalanx, then traction along the phalanx: its base was then pushed into contact with the head of the proximal phalanx. Splinting was applied with the joint in slight flexion. PMID:6823005

  13. Biomimetic myoelectric hand with voluntary control of finger angle and compliance.

    PubMed

    Okuno, R; Akazawa, K; Yoshida, M

    1999-01-01

    The purpose of this study was to develop a new type of myoelectrically controlled biomimetic prosthetic hand which has almost the same dynamics as that of the neuromuscular control system of the finger muscles, and in mechanical properties of the muscles and of the stretch reflex. One of the characteristic features of the neuromuscular control system in man is the increase in the compliance around the joint with decreasing activity of the muscle. Our prosthetic hand consisted of two surface EMG signal processing units, a digital servo system for a DC motor and 1 d.o.f. mechanical hand with three fingers. The dynamics of the neuromuscular control system including variation of the compliance around the joint was realized by using a position control system of the finger movement, force feedback and a variable gain which was modulated by the amplitude of IEMGs (rectified and smoothed EMG signals). EMG signals recorded from a pair of antagonistic muscles used to flex or to extend the wrist were used as control signals. It was shown that the finger angle and the compliance of the prosthetic hand could be controlled voluntarily with EMG signals, and that an amputee could grasp a soft object easily with the prosthetic hand. Utility of the biomimetic prosthetic hand was shown by executing myoelectric control experiments in one healthy subject and one amputee. PMID:10612560

  14. Dorsal finger joint soft tissue loss: two case reports.

    PubMed

    Bervar, M

    2003-01-01

    This article brings our experience, standpoints and management guidelines for early reconstruction of traumatic soft tissue loss on the dorsal aspect of the finger joints, with the aim of preserving acceptable late functional ability of the hand. Two interesting and unusual cases of reconstruction are presented. PMID:14989334

  15. Automatic finger joint synovitis localization in ultrasound images

    NASA Astrophysics Data System (ADS)

    Nurzynska, Karolina; Smolka, Bogdan

    2016-04-01

    A long-lasting inflammation of joints results between others in many arthritis diseases. When not cured, it may influence other organs and general patients' health. Therefore, early detection and running proper medical treatment are of big value. The patients' organs are scanned with high frequency acoustic waves, which enable visualization of interior body structures through an ultrasound sonography (USG) image. However, the procedure is standardized, different projections result in a variety of possible data, which should be analyzed in short period of time by a physician, who is using medical atlases as a guidance. This work introduces an efficient framework based on statistical approach to the finger joint USG image, which enables automatic localization of skin and bone regions, which are then used for localization of the finger joint synovitis area. The processing pipeline realizes the task in real-time and proves high accuracy when compared to annotation prepared by the expert.

  16. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Finger joint metal/metal constrained uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3200 Finger joint metal/metal constrained uncemented prosthesis. (a) Identification. A finger joint...

  17. 21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Finger joint metal/polymer constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3220 Finger joint metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint...

  18. 21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Finger joint metal/polymer constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3220 Finger joint metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint...

  19. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Finger joint metal/metal constrained uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3200 Finger joint metal/metal constrained uncemented prosthesis. (a) Identification. A finger joint...

  20. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Finger joint metal/metal constrained uncemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3200 Finger joint metal/metal constrained uncemented prosthesis. (a) Identification. A finger joint...

  1. 21 CFR 888.3210 - Finger joint metal/metal constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Finger joint metal/metal constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3210 Finger joint metal/metal constrained cemented prosthesis. (a) Identification. A finger joint metal/metal...

  2. 21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Finger joint metal/polymer constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3220 Finger joint metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint...

  3. 21 CFR 888.3210 - Finger joint metal/metal constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Finger joint metal/metal constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3210 Finger joint metal/metal constrained cemented prosthesis. (a) Identification. A finger joint metal/metal...

  4. 21 CFR 888.3210 - Finger joint metal/metal constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Finger joint metal/metal constrained cemented... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3210 Finger joint metal/metal constrained cemented prosthesis. (a) Identification. A finger joint metal/metal...

  5. 21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Finger joint metal/polymer constrained cemented... metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint metal/polymer..., 1996 for any finger joint metal/polymer constrained cemented prosthesis that was in...

  6. 21 CFR 888.3220 - Finger joint metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Finger joint metal/polymer constrained cemented... metal/polymer constrained cemented prosthesis. (a) Identification. A finger joint metal/polymer..., 1996 for any finger joint metal/polymer constrained cemented prosthesis that was in...

  7. Static hand gesture recognition based on finger root-center-angle and length weighted Mahalanobis distance

    NASA Astrophysics Data System (ADS)

    Chen, Xinghao; Shi, Chenbo; Liu, Bo

    2016-04-01

    Static hand gesture recognition (HGR) has drawn increasing attention in computer vision and human-computer interaction (HCI) recently because of its great potential. However, HGR is a challenging problem due to the variations of gestures. In this paper, we present a new framework for static hand gesture recognition. Firstly, the key joints of the hand, including the palm center, the fingertips and finger roots, are located. Secondly, we propose novel and discriminative features called root-center-angles to alleviate the influence of the variations of gestures. Thirdly, we design a distance metric called finger length weighted Mahalanobis distance (FLWMD) to measure the dissimilarity of the hand gestures. Experiments demonstrate the accuracy, efficiency and robustness of our proposed HGR framework.

  8. SU-E-T-171: Evaluation of the Analytical Anisotropic Algorithm in a Small Finger Joint Phantom Using Monte Carlo Simulation

    SciTech Connect

    Chow, J; Owrangi, A; Jiang, R

    2014-06-01

    Purpose: This study investigated the performance of the anisotropic analytical algorithm (AAA) in dose calculation in radiotherapy concerning a small finger joint. Monte Carlo simulation (EGSnrc code) was used in this dosimetric evaluation. Methods: Heterogeneous finger joint phantom containing a vertical water layer (bone joint or cartilage) sandwiched by two bones with dimension 2 × 2 × 2 cm{sup 3} was irradiated by the 6 MV photon beams (field size = 4 × 4 cm{sup 2}). The central beam axis was along the length of the bone joint and the isocenter was set to the center of the joint. The joint width and beam angle were varied from 0.5–2 mm and 0°–15°, respectively. Depth doses were calculated using the AAA and DOSXYZnrc. For dosimetric comparison and normalization, dose calculations were repeated in water phantom using the same beam geometry. Results: Our AAA and Monte Carlo results showed that the AAA underestimated the joint doses by 10%–20%, and could not predict joint dose variation with changes of joint width and beam angle. The calculated bone dose enhancement for the AAA was lower than Monte Carlo and the depth of maximum dose for the phantom was smaller than that for the water phantom. From Monte Carlo results, there was a decrease of joint dose as its width increased. This reflected the smaller the joint width, the more the bone scatter contributed to the depth dose. Moreover, the joint dose was found slightly decreased with an increase of beam angle. Conclusion: The AAA could not handle variations of joint dose well with changes of joint width and beam angle based on our finger joint phantom. Monte Carlo results showed that the joint dose decreased with increase of joint width and beam angle. This dosimetry comparison should be useful to radiation staff in radiotherapy related to small bone joint.

  9. Comparative morphometry of coxal joint angles.

    PubMed

    Sugiyama, S; Fujiwara, K

    1997-10-01

    The angles related to the coxal joints were comparatively studied in four-limbed walking animals and two-limbed ones including man and birds. Between animals with both types of walking, no significant difference was observed in the neck-shaft angles (NSA), which was equivalent to the acetabulum angles (ACA) at the connection of the femoral head with the acetabulum. The anteversion angles (AVA) were equivalent to the horizontal ACA. Canine species showed two different forms of the femoral neck with or without modification by the femoral AVA, probably being breed-specific and nutrition-dependent. In the narrow-striped wallaby as well as avian species, the femoral head showed a postversion with a minus-version angle for lifting the body axis in the frontal and upward direction to hold the whole body weight on the hind-limbs, in particular at the anterior part of the acetabulum. In man, the connection between the femur and acetabulum greatly varied among individuals, possibly according to differences in the life style. PMID:9353634

  10. Rotatory subluxation of the metacarpophalangeal index finger joint: a case report.

    PubMed

    Teo, Ken; Berger, Anthony

    2013-01-01

    We report a case of rotatory subluxation of the metacarpophalangeal joint (MCPJ) of the finger. A 40-year-old man sustained an open injury to his index finger following an explosive injury. Radiographs showed rotatory subluxation of the index finger MCPJ. The index finger extensor digitorium was found interposed in the MCPJ, with a complete tear of the radial collateral ligament. Treatment was by open reduction and repair of the collateral ligament and the extensor tendon. A high level of clinical suspicion is needed to diagnose this entity. PMID:23413862

  11. Fractal dimension and unscreened angles measured for radial viscous fingering.

    PubMed

    Praud, Olivier; Swinney, Harry L

    2005-07-01

    We have examined fractal patterns formed by the injection of air into oil in a thin (0.127 mm) layer contained between two cylindrical glass plates of 288 mm diameter (a Hele-Shaw cell), for pressure differences in the range 0.25 < or = DeltaP < or = 1.75 atm. We find that an asymptotic structure is reached at large values of the ratio r/b, where r is the pattern radius and b the gap between the plates. Both the driving force and the size of the pattern, which reaches r/b = 900, are far larger than in past experiments. The fractal dimension D0 of the pattern for large r/b is 1.70 +/- 0.02. Further, the generalized dimensions D(q) of the pattern are independent of q , D(q) approximately 1.70 for the range examined, -11 < q < 17; thus the pattern is self-similar within the experimental uncertainty. The results for D(q) agree well with recent calculations for diffusion-limited aggregation (DLA) clusters. We have also measured the probability distribution of unscreened angles. At late times, the distribution approaches a universal (i.e., forcing and size-independent) asymptotic form that has mean 145 degrees Celsius and standard deviation 36 degrees Celsius. These results indicate that the distribution function for the unscreened angle is an invariant property of the growth process. PMID:16089960

  12. Joint sense, muscle sense, and their combination as position sense, measured at the distal interphalangeal joint of the middle finger.

    PubMed Central

    Gandevia, S C; McCloskey, D I

    1976-01-01

    1. An anatomical peculiarity allows the hand to be positioned so that the terminal phalanx of the middle finger cannot be moved by voluntary effort. When positioned in this way only joint and cutaneous mechanisms subserve position sense. By altering the position of the hand the muscles are again engaged and able to move the finger. Moving the joint then also excites muscular afferents. 2. The position sense of twelve subjects was assessed with and without engagement of the muscles at the joint. Three tests were used in which either angular displacement, angular velocity or duration of displacement were held constant. 3. When muscular attachment was restored, performance in all tests was greatly enhanced. As engagement of the muscles caused little change in the 'stiffness' of the joint, it is unlikely that the improved performance resulted from increased discharges from the joint receptors. Cutaneous mechanisms are unlikely to mediate this improvement as they are likely to have been unaffected by engagement of muscles. It is concluded that intramuscular receptors are partly responsible for normal position sense. 4. In seven of the twelve subjects the test finger was anaesthetized to isolate the contribution of intramuscular receptors. This muscle sense was variable. In some subjects it provided accurate kinaesthetic information but in others the information was crude. If with the test finger anaesthetized subjects exerted voluntary tension with the muscles that move the joint the muscle sense was improved. Images Plate 1 PMID:978533

  13. Noninvasively measuring oxygen saturation of human finger-joint vessels by multi-transducer functional photoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Deng, Zijian; Li, Changhui

    2016-06-01

    Imaging small blood vessels and measuring their functional information in finger joint are still challenges for clinical imaging modalities. In this study, we developed a multi-transducer functional photoacoustic tomography (PAT) system and successfully imaged human finger-joint vessels from ˜1 mm to <0.2 mm in diameter. In addition, the oxygen saturation (SO2) values of these vessels were also measured. Our results demonstrate that PAT can provide both anatomical and functional information of individual finger-joint vessels with different sizes, which might help the study of finger-joint diseases, such as rheumatoid arthritis.

  14. Menstrual cyclicity of finger joint size and grip strength in patients with rheumatoid arthritis.

    PubMed Central

    Rudge, S R; Kowanko, I C; Drury, P L

    1983-01-01

    Daily measurements of finger joint size, grip strength, and body weight have been made throughout 2 complete menstrual cycles in 7 female patients with rheumatoid arthritis and 6 healthy female controls. Sine wave analysis showed significant individual cyclical rhythms (p less than 0.05) for finger joint size (5 patients, 4 controls), nude weight (5 patients, 3 controls), and grip strength (4 patients, 3 controls). In addition analysis of group data, on the assumption of a 28-day cycle, showed a significant cycle for grip strength in the rheumatoid patients, with a nadir at 28 days. In the normal subjects much of the cyclical variation in finger joint size could be explained by changes in weight (median 49.5%), but this was not so in patients with rheumatoid arthritis (median 2.8%). These findings suggest the existence of a cyclical variation in disease activity in rheumatoid arthritis. PMID:6882039

  15. Novel titanium-aluminum joints for cryogenic cold finger structures

    NASA Astrophysics Data System (ADS)

    Meehan, H. M.; Sweet, R. C.

    For optimum performance, the sensors employed in airborne detection and surveillance systems must be maintained at low temperatures. The containing wall of the expansion volume of a Stirling cycle cooler may provide the low temperature surface for mounting the sensors. IR detectors are commonly mounted on copper heat exchanger surfaces. A stainless steel member is employed to thermally isolate and structurally stabilize such surfaces. It is pointed out that the use of an aluminum-titanium cold finger results in a considerable weight reduction. The present investigation is concerned with an attempt to obtain such structures with the aid of a technique involving the casting of molten aluminum onto an appropriately dimensioned and positioned titanium member, taking into account the fact that aluminum readily wets and bonds to clean titanium surfaces. The casting is then machined to provide the form and structure desired. It is concluded that aluminum-titanium cast structures offer good potential for use as cryogenic cold finger assemblies.

  16. Assessment of finger joint inflammation by diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Hielscher, Andreas H.; Klose, Alexander D.; Scheel, Alexander K.; Backhaus, Marina; Netz, Uwe J.; Beuthan, Juergen

    2003-10-01

    Inflammatory processes as they occur during rheumatoid arthritis (RA) lead to changes in the optical properties of joint tissues and fluids. These changes occur early on in the disease process and can potentially be used as diagnostic parameter. In this work we report on in vivo studies involving 12 human subjects, which show the potential of diffuse optical tomographic techniques for the diagnosis of inflammatory processes in proximal interphalangeal (PIP) joints.

  17. Radiologically defined osteoarthrosis in the finger joints of adult residents of Zagreb.

    PubMed

    Cvijetić, S; Dekanić, D; Kurtagić, N; Roić, G

    1994-09-01

    Degenerative changes in the finger joints were studied in 550 Zagreb inhabitants, above the age of 45. The sample was selected by the method of unproportional stratified choice according to age and sex. Radiographs of both hands were taken and osteoarthrosis on the proximal and distal interphalangeal joints was graded according to the five-point Kellgren-Lawrence scale. Body weight, height and arterial blood pressure were measured and occupational work load was evaluated. The prevalence of osteoarthrosis in the finger joints was significantly higher in women (40.9%) than in men (24.8%). It increased with age so that 18.7% of men and 15.0% of women aged 45-54 had finger osteoarthrosis compared to 36.3% of men and 68.2% of women aged 75 and older. Distal interphalangeal joints were more often involved (22.8% of men and 37.9% of women) than the proximal ones (9.7% of men and 19.6% of women). The factors most closely associated with osteoarthrosis were age and body weight. Occupational work load, as classified in this study, was not significantly related to the development of osteoarthrosis, except in the group of housewives, in whom the prevalence of finger arthrosis was greater than in the other groups of women. PMID:7763184

  18. The effect of knee joint angle on torque control.

    PubMed

    Sosnoff, Jacob J; Voudrie, Stefani J; Ebersole, Kyle T

    2010-01-01

    The purpose of the author's investigation was to examine the effect of knee joint angle on torque control of the quadriceps muscle group. In all, 12 healthy adults produced maximal voluntary contractions and submaximal torque (15, 30, and 45% MVC [maximal voluntary contraction]) at leg flexion angles of 15 degrees , 30 degrees , 60 degrees , and 90 degrees below the horizontal plane. As expected, MVC values changed with respect to joint angle with maximum torque output being greatest at 60 degrees and least at 15 degrees . During the submaximal tasks, participants appropriately scaled their torque output to the required targets. Absolute variability (i.e., standard deviation) of torque output was greatest at 60 degrees and 90 degrees knee flexion. However, relative variability as indexed by coefficient of variation (CV) decreased as joint angle increased, with the greatest CV occurring at 15 degrees . These results are congruent with the hypothesis that joint angle influences the control of torque. PMID:19906637

  19. Small Finger Snapping due to Retinacular Ligament Injury at the Level of Proximal Interphalangeal Joint

    PubMed Central

    Lee, Young-Keun; Lee, Jun-Mo; Lee, Malrey

    2015-01-01

    Abstract Pathological snapping secondary to posttraumatic subluxation of the extensor tendon at proximal interphalangeal joint (PIPJ) of the finger is rare. Here, we want to describe a patient with snapping of the left small finger at PIPJ due to retinacular ligament injury. A 24-year-old man was admitted because of a 5-year history of a snapping sound in the left small finger. On examination, the radial side lateral band of the small finger was dislocated volarly at the level PIPJ with flexion of >50°, which was clearly felt over the skin. There was an obvious snapping sound at the time of dislocation. There was no specific radiographic abnormality. With the patient under regional anesthesia, exploration through a zigzag skin incision over the dorsum of the PIPJ revealed that the retinacular ligament complex was injured. We also found a partial tear in PIPJ capsule, through the incision of the injured retinacular ligament complex. We repaired the joint capsule and retinacular ligament complex with prolene 4–0. Postoperatively the small finger was immobilized in a below-elbow plaster splint with full extension of the fingers for 1 week, then dynamic splinting was advised for another 5 weeks and unrestricted full active motion was allowed at the 6th week. At the 6-month follow-up, the patient had regained full range of motion with no discomfort, and there was no sign of recurrence. We stress that when there is snapping over the dorsum of the PIPJ of the finger, the clinician should suspect rupture of the retinacular ligaments, especially in minor trauma patients. Primary repair of retinacular ligaments and dynamic splinting provided satisfactory results without recurrence in our patient.

  20. Small Finger Snapping due to Retinacular Ligament Injury at the Level of Proximal Interphalangeal Joint

    PubMed Central

    Lee, Young-Keun; Lee, Jun-Mo; Lee, Malrey

    2015-01-01

    Abstract Pathological snapping secondary to posttraumatic subluxation of the extensor tendon at proximal interphalangeal joint (PIPJ) of the finger is rare. Here, we want to describe a patient with snapping of the left small finger at PIPJ due to retinacular ligament injury. A 24-year-old man was admitted because of a 5-year history of a snapping sound in the left small finger. On examination, the radial side lateral band of the small finger was dislocated volarly at the level PIPJ with flexion of >50°, which was clearly felt over the skin. There was an obvious snapping sound at the time of dislocation. There was no specific radiographic abnormality. With the patient under regional anesthesia, exploration through a zigzag skin incision over the dorsum of the PIPJ revealed that the retinacular ligament complex was injured. We also found a partial tear in PIPJ capsule, through the incision of the injured retinacular ligament complex. We repaired the joint capsule and retinacular ligament complex with prolene 4–0. Postoperatively the small finger was immobilized in a below-elbow plaster splint with full extension of the fingers for 1 week, then dynamic splinting was advised for another 5 weeks and unrestricted full active motion was allowed at the 6th week. At the 6-month follow-up, the patient had regained full range of motion with no discomfort, and there was no sign of recurrence. We stress that when there is snapping over the dorsum of the PIPJ of the finger, the clinician should suspect rupture of the retinacular ligaments, especially in minor trauma patients. Primary repair of retinacular ligaments and dynamic splinting provided satisfactory results without recurrence in our patient. PMID:26091481

  1. Simultaneous Volar Dislocation of Distal Interphalangeal Joint and Volar Fracture-Subluxation of Proximal Interphalangeal Joint of Little Finger: A New Mechanism of Injury.

    PubMed

    Mozaffarian, Kamran; Bayatpour, Abdollah; Vosoughi, Amir Reza

    2016-10-01

    Simultaneous volar dislocation of distal interphalangeal (DIP) joint and volar fracture-subluxation of proximal interphalangeal (PIP) joint of the same finger has not been reported yet. A 19-year-old man was referred due to pain on the deformed left little finger after a ball injury. Radiographs showed volar dislocation of the DIP joint and dorsal lip fracture of the middle phalanx with volar subluxation of PIP joint of the little finger. This case was unique in terms of the mechanism of injury which was hyperflexion type in two adjacent joints of the same finger. The patient was treated by closed reduction of DIP joint dislocation and open reduction and internal fixation of the PIP joint fracture-subluxation and application of dorsal external fixator due to instability. Finally, full flexion of the PIP joint and full extension of the DIP joint were obtained but with 10 degree extension lag at the PIP joint and DIP joint flexion ranging from 0 degree to 30 degrees. Some loss of motion in small joints of the fingers after hyperflexion injuries should be expected. PMID:27595966

  2. Computer-aided classification of rheumatoid arthritis in finger joints using frequency domain optical tomography

    NASA Astrophysics Data System (ADS)

    Klose, C. D.; Kim, H. K.; Netz, U.; Blaschke, S.; Zwaka, P. A.; Mueller, G. A.; Beuthan, J.; Hielscher, A. H.

    2009-02-01

    Novel methods that can help in the diagnosis and monitoring of joint disease are essential for efficient use of novel arthritis therapies that are currently emerging. Building on previous studies that involved continuous wave imaging systems we present here first clinical data obtained with a new frequency-domain imaging system. Three-dimensional tomographic data sets of absorption and scattering coefficients were generated for 107 fingers. The data were analyzed using ANOVA, MANOVA, Discriminant Analysis DA, and a machine-learning algorithm that is based on self-organizing mapping (SOM) for clustering data in 2-dimensional parameter spaces. Overall we found that the SOM algorithm outperforms the more traditional analysis methods in terms of correctly classifying finger joints. Using SOM, healthy and affected joints can now be separated with a sensitivity of 0.97 and specificity of 0.91. Furthermore, preliminary results suggest that if a combination of multiple image properties is used, statistical significant differences can be found between RA-affected finger joints that show different clinical features (e.g. effusion, synovitis or erosion).

  3. Photoacoustic tomography of the human finger: towards the assessment of inflammatory joint diseases

    NASA Astrophysics Data System (ADS)

    van Es, P.; Biswas, S. K.; Bernelot Moens, H. J.; Steenbergen, W.; Manohar, S.

    2015-03-01

    Inflammatory arthritis is often manifested in finger joints. The growth of new or withdrawal of old blood vessels can be a sensitive marker for these diseases. Photoacoustic (PA) imaging has great potential in this respect since it allows the sensitive and highly resolved visualization of blood. We systematically investigated PA imaging of finger vasculature in healthy volunteers using a newly developed PA tomographic system. We present the PA results which show excellent detail of the vasculature. Vessels with diameters ranging between 100 μm and 1.5 mm are visible along with details of the skin, including the epidermis and the subpapillary plexus. The focus of all the studies is at the proximal and distal interphalangeal joints, and in the context of ultimately visualizing the inflamed synovial membrane in patients. This work is important in laying the foundation for detailed research into PA imaging of the phalangeal vasculature in patients suffering from rheumatoid arthritis.

  4. Integrated photoacoustic and diffuse optical tomography system for imaging of human finger joints in vivo.

    PubMed

    Xi, Lei; Jiang, Huabei

    2016-03-01

    In this study, we developed a dual-modality tomographic system that integrated photoacoustic imaging (PAI) and diffuse optical tomography (DOT) into a single platform for imaging human finger joints with fine structures and associated optical properties. In PAI, spherical focused transducers were utilized to collect acoustic signals, and the concept of virtual detector was applied in a conventional back-projection algorithm to improve the image quality. A finite-element based reconstruction algorithm was employed to quantitatively recover optical property distribution in the objects for DOT. The phantom results indicate that PAI has a maximum lateral resolution of 70 µm in resolving structures of targets. DOT was able to recover both optical absorption and reduced scattering coefficients of targets accurately. To validate the potential of this system in clinical diagnosis of joint diseases, the distal interphalangeal (DIP) joints of 4 healthy female volunteers were imaged. We successfully obtained high-resolution images of the phalanx and the surrounding soft tissue via PAI, and recovered both optical absorption and reduced scattering coefficients of phalanx using DOT. The in vivo results suggest that this dual-modality system has the potential for the early diagnosis of joint diseases such as osteoarthritis (OA) and rheumatoid arthritis (RA). Integrated PAI/DOT imaging interface (top) and typical reconstruction of structures and associated optical properties of a female finger joint via PAI and DOT (bottom). PMID:26431473

  5. High resolution three-dimensional photoacoustic imaging of human finger joints in vivo

    NASA Astrophysics Data System (ADS)

    Xi, Lei; Jiang, Huabei

    2015-08-01

    We present a method for noninvasively imaging the hand joints using a three-dimensional (3D) photoacoustic imaging (PAI) system. This 3D PAI system utilizes cylindrical scanning in data collection and virtual-detector concept in image reconstruction. The maximum lateral and axial resolutions of the PAI system are 70 μm and 240 μm. The cross-sectional photoacoustic images of a healthy joint clearly exhibited major internal structures including phalanx and tendons, which are not available from the current photoacoustic imaging methods. The in vivo PAI results obtained are comparable with the corresponding 3.0 T MRI images of the finger joint. This study suggests that the proposed method has the potential to be used in early detection of joint diseases such as osteoarthritis.

  6. Multipixel system for gigahertz frequency-domain optical imaging of finger joints

    NASA Astrophysics Data System (ADS)

    Netz, Uwe J.; Beuthan, Jürgen; Hielscher, Andreas H.

    2008-03-01

    Frequency-domain optical imaging systems have shown great promise for characterizing blood oxygenation, hemodynamics, and other physiological parameters in human and animal tissues. However, most of the frequency domain systems presented so far operate with source modulation frequencies below 150MHz. At these low frequencies, their ability to provide accurate data for small tissue geometries such as encountered in imaging of finger joints or rodents is limited. Here, we present a new system that can provide data up to 1GHz using an intensity modulated charged coupled device camera. After data processing, the images show the two-dimensional distribution of amplitude and phase of the light modulation on the finger surface. The system performance was investigated and test measurements on optical tissue phantoms were taken to investigate whether higher frequencies yield better signal-to-noise ratios (SNRs). It could be shown that local changes in optical tissue properties, as they appear in the initial stages of rheumatoid arthritis in a finger joint, are detectable by simple image evaluation, with the range of modulation frequency around 500MHz proving to yield the highest SNR.

  7. Applied Joint-Space Torque and Stiffness Control of Tendon-Driven Fingers

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E.; Platt, Robert, Jr.; Wampler, Charles W.; Hargrave, Brian

    2010-01-01

    Existing tendon-driven fingers have applied force control through independent tension controllers on each tendon, i.e. in the tendon-space. The coupled kinematics of the tendons, however, cause such controllers to exhibit a transient coupling in their response. This problem can be resolved by alternatively framing the controllers in the joint-space of the manipulator. This work presents a joint-space torque control law that demonstrates both a decoupled and significantly faster response than an equivalent tendon-space formulation. The law also demonstrates greater speed and robustness than comparable PI controllers. In addition, a tension distribution algorithm is presented here to allocate forces from the joints to the tendons. It allocates the tensions so that they satisfy both an upper and lower bound, and it does so without requiring linear programming or open-ended iterations. The control law and tension distribution algorithm are implemented on the robotic hand of Robonaut-2.

  8. [The development of a finger joint phantom for the optical simulation of early inflammatory rheumatic changes].

    PubMed

    Prapavat, V; Runge, W; Mans, J; Krause, A; Beuthan, J; Müller, G

    1997-11-01

    In the field of rheumatology, conventional diagnostic methods permit the detection only of advanced stages of the disease, which is at odds with the current clinical demand for the early diagnosis of inflammatory rheumatic diseases. Prompted by current needs, we developed a finger joint phantom that enables the optical and geometrical simulation of an early stage of rheumatoid arthritis (RA). The results presented here form the experimental basis for an evaluation of new RA diagnostic systems based on near infrared light. The early stage of RA is characterised mainly by a vigorous proliferation of the synovial membrane and clouding of the synovial fluid. Using a double-integrating-sphere technique, the absorption and scattering coefficients (mua, mus') are experimentally determined for healthy and pathologically altered synovial fluid and capsule tissue. Using a variable mixture of Intralipid Indian ink and water as a scattering/absorption medium, the optical properties of skin, synovial fluid or capsule can be selected individually. Since the optical and geometrical properties of bone tissue remain constant in early-stage RA, a solid material is used for its simulation. Using the finger joint phantom described herein, the optical properties of joint regions can be adjusted specifically, enabling an evaluation of their effects on an optical signal--for example, during fluorography--and the investigation of these effects for diagnostically useful information. The experimental foundation for the development of a new optical system for the early diagnosis of RA has now been laid. PMID:9490122

  9. High-Resolution Interleaved Water-Fat MR Imaging of Finger Joints with Chemical-Shift Elimination

    PubMed Central

    You, Zhigang; Seo, Gwysuk; Lerner, Amy; Totterman, Saara; Ritchlin, Christopher; Monu, Johnny

    2015-01-01

    Purpose To study the use of an interleaved water-fat (IWF) sequence with a custom-made RF coil for high-resolution imaging of arthritic finger joints. Materials and Methods High-resolution finger MRI was performed using a custom-made dedicated RF receiver coil and an IWF sequence. A phantom, a cadaver finger specimen and the fingers of two normal controls and six arthritic subjects were imaged with a resolution of 156×156×600 microns. The appearance of anatomic structures on the IWF images were compared with images acquired with a regular sequence. The images were reviewed by two musculoskeletal radiologists for the depiction of anatomical structures and for the presence of abnormalities. Results The high-resolution images revealed detailed structures of the finger joints not detectable using typical clinical resolution. The IWF sequence gave more realistic depiction of subchondral bone thickness, and avoided false bone erosions displayed in the regular sequence. It also allowed better visualization of ligaments and tendons. Conclusion This pilot study shows the feasibility and the potential usefulness of high-resolution IWF imaging for finger joint evaluation. This technique may be useful for the diagnosis and treatment assessment of arthritis, and for the study of joint disease pathogenesis. PMID:21182147

  10. IMU-Based Joint Angle Measurement for Gait Analysis

    PubMed Central

    Seel, Thomas; Raisch, Jorg; Schauer, Thomas

    2014-01-01

    This contribution is concerned with joint angle calculation based on inertial measurement data in the context of human motion analysis. Unlike most robotic devices, the human body lacks even surfaces and right angles. Therefore, we focus on methods that avoid assuming certain orientations in which the sensors are mounted with respect to the body segments. After a review of available methods that may cope with this challenge, we present a set of new methods for: (1) joint axis and position identification; and (2) flexion/extension joint angle measurement. In particular, we propose methods that use only gyroscopes and accelerometers and, therefore, do not rely on a homogeneous magnetic field. We provide results from gait trials of a transfemoral amputee in which we compare the inertial measurement unit (IMU)-based methods to an optical 3D motion capture system. Unlike most authors, we place the optical markers on anatomical landmarks instead of attaching them to the IMUs. Root mean square errors of the knee flexion/extension angles are found to be less than 1° on the prosthesis and about 3° on the human leg. For the plantar/dorsiflexion of the ankle, both deviations are about 1°. PMID:24743160

  11. Revisiting the Force-Joint Angle Relationship After Eccentric Exercise.

    PubMed

    Welsh, Molly C; Allen, David L; Batliner, Matthew E; Byrnes, William C

    2015-12-01

    The purpose of this study was to evaluate force-angle curve fitting techniques pre-eccentric exercise, quantify changes in curve characteristics postexercise, and examine the relationship between curve changes and markers of muscle damage. Fourteen males unaccustomed to eccentric exercise performed 60 eccentric muscle actions of the elbow flexors. Maximal voluntary isometric force was measured throughout a range of angles pre- (Pre1 and Pre2), immediately post (IP), and 1, 2, 4, and 7 days postexercise. Force-angle curves for each visit were constructed using second-order polynomials. Changes in curve characteristics (optimal angle, peak force, curve height), range of motion, soreness, and creatine kinase activity were quantified. Optimal joint angle and force at optimal angle were significantly correlated from Pre1 to Pre2 (ICC = 0.821 and 0.979, respectively). Optimal angle was significantly right shifted (p = 0.035) by 10.4 ± 12.9° from Pre2 to IP and was restored by 1 day post exercise. Interestingly, the r value for curve fit was significantly decreased (p < 0.001) from Pre2 (r = 0.896) to IP (r = 0.802) and 1 day post exercise (r = 0.750). Curve height was significantly decreased (39%) IP and restored to pre-exercise height by 4 days postexercise. There was no correlation between optimal angle or curve height and other damage markers. In conclusion, force-angle relationships can be accurately described using second-order polynomials. After eccentric exercise, the force-angle curve is flattened and shifted (downward and rightward), but these changes are not correlated to other markers of muscle damage. Changes in the force-angle relationship are multifaceted, but determining the physiological significance of these changes requires further investigation. PMID:25970492

  12. Effect of fence height on joint angles of agility dogs.

    PubMed

    Birch, Emily; Leśniak, Kirsty

    2013-12-01

    The Kennel Club (KC) and United Kingdom Agility (UKA) govern major dog agility competitions in the UK. Dogs are categorised into different jump heights depending on their height at the withers, with fence heights ranging from 300 to 650 mm for both organisations. Dogs fall into one of three height categories when competing under KC rules and one of four height categories under UKA rules. The aim of this study was to investigate the influence of an additional height category for agility dogs measuring over 430 mm at the withers. Jump heights were selected that related to the percentage of body height that dogs of 430 mm (7% lower) and 431 mm (51% higher) height at the withers would be encouraged to jump under UKA regulations without the addition of their fourth ('standard height') category. Joint angles were determined from anatomical markers placed on the forelimb and hind limb joints, and at six points along the vertebral column. As fence height increased, flexion of the scapulohumeral joint increased significantly for both the take-off and bascule (arc) phases of the jump. The increase in flexion as a consequence of the increase in fence height is likely to result in intensified stretching of the biceps brachii and supraspinatus muscles. In addition, increasing fence high resulted in an increase in the sacroiliac joint angle during take-off. PMID:24360736

  13. Two- and three-dimensional optical tomography of finger joints for diagnostics of rheumatoid arthritis

    NASA Astrophysics Data System (ADS)

    Klose, Alexander D.; Hielscher, Andreas H.; Hanson, Kenneth M.; Beuthan, Juergen

    1998-12-01

    Rheumatoid arthritis (RA) is one of the most common diseases of human joints. This progressive disease is characterized by an inflammation process that originates in the inner membrane (synovalis) of the capsule and spreads to other parts of the joint. In early stages the synovalis thickness and the permeability of this membrane changes. This leads to changes in the optical parameters of the synovalis and the synovial fluid (synovia), which occupies the space between the bones. The synovia changes from a clear yellowish fluid to a turbid grayish substance. In this work we present 2 and 3-dimensional reconstruction schemes for optical tomography of the finger joints. Our reconstruction algorithm is based on the diffusion approximation and employs adjoint differentiation techniques for the gradient calculation of the objective function with respect to the spatial distribution of optical properties. In this way, the spatial distribution of optical properties within the joints is reconstructed with high efficiency and precision. Volume information concerning the synovial space and the capsula are provided. Furthermore, it is shown that small changes of the scattering coefficients can be monitored. Therefore, optical tomography has the potential of becoming a useful tool for the early diagnosis and monitoring of disease progression in RA.

  14. Joint angle estimation with accelerometers for dynamic postural analysis.

    PubMed

    Ma, Jianting; Kharboutly, Haissam; Benali, Abderraouf; Benamar, Faïz; Bouzit, Mourad

    2015-10-15

    This paper presents a new accelerometer based method for estimating the posture of a subject standing on a dynamic perturbation platform. The induced perturbation is used to study the control mechanisms as well as the balance requirements that regulate the upright standing. These perturbations are translated into different intensity levels of speed and acceleration along longitudinal and lateral directions of motion. In our method, the human posture is modeled by a tridimensional, three-segment inverted pendulum which simultaneously takes into account both the anterior-posterior and medio-lateral strategies of hip and ankle. Four tri-axial accelerometers are used her, one accelerometer is placed on the platform, and the other three are attached to a human subject. Based on the results, the joint angle estimated compare closely to measurements from magnetic encoders placed on an articulated arm joint. The results were also comparable to those found when using a high-end optical motion capture system coupled with advanced biomechanical simulation software. This paper presents the comparisons of our accelerometer-based method with encoder and optical marker based method of the estimated joint angles under different dynamics perturbations. PMID:26338097

  15. Classification of optical tomographic images of rheumatoid finger joints with support vector machines

    NASA Astrophysics Data System (ADS)

    Balasubramanyam, Vivek; Hielscher, Andreas H.

    2005-04-01

    Over the last years we have developed a sagittal laser optical tomographic (SLOT) imaging system for the diagnosis and monitoring of inflammatory processes in proximal interphalangeal (PIP) joint of patients with rheumatoid arthritis (RA). While cross sectional images of the distribution of optical properties can now be generated easily, clinical interpretation of these images remains a challenge. In first clinical studies involving 78 finger joints, we compared optical tomographs to ultrasound images and clinical analyses. Receiver-operator curves (ROC) were generated using various image parameters, such as minimum and maximum scattering or absorption coefficients. These studies resulted in specificities and sensitivities in the range of 0.7 to 0.76. Recently, we have trained support vector machines (SVMs) to classify images of healthy and diseased joints. By eliminating redundancy using feature selection, we are achieving sensitivities of 0.72 and specificities up to 1.0. Studies with larger patient groups are necessary to validate these findings; but these initial results support the expectation that SVMs and other machine learning techniques can considerably improve image interpretation analysis in optical tomography.

  16. Tumoral pseudogout of the proximal interphalangeal joint of a finger: a case report and literature review.

    PubMed

    Park, Hyo Jung; Chung, Hye Won; Oh, Tack Sun; Lee, Jong-Seok; Song, Joon Seon; Park, Yong-Koo

    2016-07-01

    Tumoral pseudogout is a rare clinical form of calcium pyrophosphate dihydrate crystal deposition disease. Tumoral pseudogout can mimic other diseases such as chondroid tumor, tophaceous gout, or tumoral calcinosis. Its radiological features have been presented in some case reports, but no specific radiographic features have been identified. Here, we report an unusual case of recurrent tumoral pseudogout involving the proximal interphalangeal joint of the right long finger. This case presents with progressive radiological findings of the disease with an enlarging and recurrent calcified mass and secondary bony erosion and remodeling, along with a radiological-pathological correlation. We also review previously reported imaging findings of this disease entity, differential points in comparison to other diseases, and some key points for making the correct diagnosis. PMID:27048476

  17. Static torque-angle relation of human elbow joint estimated with artificial neural network technique.

    PubMed

    Uchiyama, T; Bessho, T; Akazawa, K

    1998-06-01

    Static relations between elbow joint angle and torque at constant muscle activity in normal volunteers were investigated with the aid of an artificial neural network technique. A subject sat on a chair and moved his upper- and forearm in a horizontal plane at the height of his shoulder. The subject was instructed to maintain the elbow joint at a pre-determined angle. The wrist was then pulled to extend the elbow joint by the gravitational force of a weight hanging from a pulley. Integrated electromyograms (IEMGs), elbow and shoulder joint angles and elbow joint torque were measured. Then the relation among IEMGs, joint angles and torque was modeled with the aid of the artificial neural network, where IEMGs and joint angles were the inputs and torque was the output. After back propagation learning, we presented various combinations of IEMGs, shoulder and elbow joint angles to the model and estimated the elbow joint torque to obtain the torque-angle relation for constant muscle activation. The elbow joint torque increased and then decreased with extension of the elbow joint. This suggests that if the forearm is displaced from an equilibrium point, the torque angle relation would not act like a simple spring. In a view of the musculoskeletal structure of the elbow joint, the relation between the elbow joint angle and the moment arm of the elbow flexor muscles seems to have a dominant effect on the torque-angle relation. PMID:9755039

  18. A multifunctional joint angle sensor with measurement adaptability.

    PubMed

    Quan, Wei; Wang, Hua; Liu, Datong

    2013-01-01

    The paper presents a multifunctional joint sensor with measurement adaptability for biological engineering applications, such as gait analysis, gesture recognition, etc. The adaptability is embodied in both static and dynamic environment measurements, both of body pose and in motion capture. Its multifunctional capabilities lay in its ability of simultaneous measurement of multiple degrees of freedom (MDOF) with a single sensor to reduce system complexity. The basic working mode enables 2DOF spatial angle measurement over big ranges and stands out for its applications on different joints of different individuals without recalibration. The optional advanced working mode enables an additional DOF measurement for various applications. By employing corrugated tube as the main body, the sensor is also characterized as flexible and wearable with less restraints. MDOF variations are converted to linear displacements of the sensing elements. The simple reconstruction algorithm and small outputs volume are capable of providing real-time angles and long-term monitoring. The performance assessment of the built prototype is promising enough to indicate the feasibility of the sensor. PMID:24217353

  19. Tests of wireless wearable sensor system in joint angle measurement of lower limbs.

    PubMed

    Watanabe, Takashi; Saito, Hiroki

    2011-01-01

    The aim of this study was to test the wireless wearable sensor system consists of inertial sensors considering application to rehabilitation. The sensor system was evaluated in measurement of hip, knee and ankle joint angles with healthy subjects comparing to those measured with a 3D motion measurement system. Then, the lower limb joint angles of elderly subjects including paralyzed subjects were measured during gait on the level floor with the sensor system. Evaluation of measured joint angles in comparison with the motion measurement system showed that mean values of the RMSE were smaller than 4 deg for all the joint angles, and mean values of the correlation coefficient were larger than 0.985 for hip and knee joint angles and about 0.90 for ankle joint angle. In measurement with elderly subjects, the sensor system showed some differences in joint angles between the paralyzed and the non-paralyzed sides. PMID:22255575

  20. Successful treatment of a guitarist with a finger joint injury using instrument-assisted soft tissue mobilization: a case report.

    PubMed

    Terry Loghmani, M; Bayliss, Amy J; Clayton, Greg; Gundeck, Evelina

    2015-12-01

    Finger injuries are common and can greatly affect a musician's quality of life. A 55-year-old man, who had injured the proximal interphalangeal joint of the left index finger 6 months prior to any intervention, was treated with a manual therapy approach incorporating instrument-assisted soft tissue mobilization (IASTM). Initial examination findings included self-reported pain and functional limitations and physical impairments that significantly impeded his ability to play the acoustic guitar. He was treated once a week for 6 weeks with IASTM, joint mobilization, therapeutic exercise, and ice massage. Additionally, a home exercise program and self-care instructions were provided. The patient gained positive outcomes with improvements in pain (Numerical Pain Rating Scale while playing the guitar: initial 5/10, discharge 1/10) and function (Disability Arm Shoulder Hand Sports-Performing Arts Optional Module: initial 75; discharge 6·25), each reaching a minimum clinically important difference. Importantly, he was able to play the guitar with minimal to no pain as desired. Physical measures also improved, including an immediate gain in finger range of motion with IASTM alone. Manual therapy approaches integrating IASTM may provide an effective conservative treatment strategy for patients with finger/hand conditions in the performing arts and other patient populations. PMID:26952165

  1. A cortically-inspired model for inverse kinematics computation of a humanoid finger with mechanically coupled joints.

    PubMed

    Gentili, Rodolphe J; Oh, Hyuk; Kregling, Alissa V; Reggia, James A

    2016-06-01

    The human hand's versatility allows for robust and flexible grasping. To obtain such efficiency, many robotic hands include human biomechanical features such as fingers having their two last joints mechanically coupled. Although such coupling enables human-like grasping, controlling the inverse kinematics of such mechanical systems is challenging. Here we propose a cortical model for fine motor control of a humanoid finger, having its two last joints coupled, that learns the inverse kinematics of the effector. This neural model functionally mimics the population vector coding as well as sensorimotor prediction processes of the brain's motor/premotor and parietal regions, respectively. After learning, this neural architecture could both overtly (actual execution) and covertly (mental execution or motor imagery) perform accurate, robust and flexible finger movements while reproducing the main human finger kinematic states. This work contributes to developing neuro-mimetic controllers for dexterous humanoid robotic/prosthetic upper-extremities, and has the potential to promote human-robot interactions. PMID:27194213

  2. Upper limb joint angle measurement in occupational health.

    PubMed

    Álvarez, Diego; Alvarez, Juan C; González, Rafael C; López, Antonio M

    2016-01-01

    Usual human motion capture systems are designed to work in controlled laboratory conditions. For occupational health, instruments that can measure during normal daily life are essential, as the evaluation of the workers' movements is a key factor to reduce employee injury- and illness-related costs. In this paper, we present a method for joint angle measurement, combining inertial sensors (accelerometers and gyroscopes) and magnetic sensors. This method estimates wrist flexion, wrist lateral deviation, elbow flexion, elbow pronation, shoulder flexion, shoulder abduction and shoulder internal rotation. The algorithms avoid numerical integration of the signals, which allows for long-time estimations without angle estimation drift. The system has been tested both under laboratory and field conditions. Controlled laboratory tests show mean estimation errors between 0.06° and of 1.05°, and standard deviation between 2.18° and 9.20°. Field tests seem to confirm these results when no ferromagnetic materials are close to the measurement system. PMID:25573165

  3. Assessing Finger Joint Biomechanics by Applying Equal Force to Flexor Tendons In Vitro Using a Novel Simultaneous Approach

    PubMed Central

    Yang, Tai-Hua; Lu, Szu-Ching; Lin, Wei-Jr; Zhao, Kristin; Zhao, Chunfeng; An, Kai-Nan; Jou, I-Ming; Lee, Pei-Yuan

    2016-01-01

    Background The flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) are critical for finger flexion. Although research has recently focused on these tendons’ coactivity, their contributions in different tasks remain unclear. This study created a novel simultaneous approach to investigate the coactivity between the tendons and to clarify their contributions in different tasks. Methods Ten human cadaveric hands were mounted on our custom frame with the FDS and FDP of the third finger looped through a mechanical pulley connected to a force transducer. Joint range of motion, tendon excursion and loading force were recorded during individual joint motion and free joint movement from rest to maximal flexion. Each flexor tendon’s moment arm was then calculated. Results In individual motions, we found that the FDP contributed more than the FDS in proximal interphalangeal (PIP) joint motion, with an overall slope of 1.34 and all FDP-to-FDS excursion (P/S) ratios greater than 1.0 with force increase. However, the FDP contributed less than the FDS in metacarpophalangeal (MCP) joint motion, with an overall slope of 0.95 and P/S ratios smaller than 1.0 throughout the whole motion except between 1.9% and 13.1% force. In free joint movement, the FDP played a greater role than the FDS, with an overall ratio of 1.37 and all P/S ratios greater than 1.0. Conclusions The new findings include differences in finger performance and excursion amounts between the FDS and FDP throughout flexion. Such findings may provide the basis for new hand models and treatments. PMID:27513744

  4. Optimal design of a six-bar linkage with one degree of freedom for an anthropomorphic three-jointed finger mechanism.

    PubMed

    Guo, G; Zhang, J; Gruver, W A

    1993-01-01

    This research concerns the design of a three-jointed, anthropomorphic, finger mechanism for use as a prosthesis or robotic end-effector. Based on a study of finger configurations for the human hand, a six-bar linkage with one degree of freedom is proposed. A model of the fingertip displacement of the mechanism is derived by a vector analysis approach. The effects of joint friction on the transmission efficiency are analysed. By measuring the joint positions of a human finger, a mathematical model of the pinching and holding configurations are developed. Optimal parameters for the finger mechanism are obtained by non-linear programming based on an objective functional involving motion posture and locus, transmission efficiency and weight subject to geometric and bionic constraints. Simulation results indicate that the mechanism is useful for a variety of prosthetic and robotic applications. PMID:8117370

  5. Morbid anatomy of ‘erosive osteoarthritis’ of the interphalangeal finger joints: an optimised scoring system to monitor disease progression in affected joints

    PubMed Central

    Verbruggen, Gust; Wittoek, Ruth; Cruyssen, Bert Vander; Elewaut, Dirk

    2010-01-01

    Objectives To develop and validate a quantitative radiographic scoring system, the Ghent University Scoring System (GUSS), with better ability to detect progression over a shorter period of time in erosive osteoarthritis (OA) of the interphalangeal (IP) finger joints compared with the existing anatomic phase scoring system. Methods Thirty IP finger joints showing erosive features at baseline or follow-up were selected from 18 patients with erosive hand OA. Posteroanterior radiographs of these joints obtained at baseline, 6 and 12 months—totalling 90 images—were used for the study. All joints were first scored according to the original anatomic phase scoring system. Erosive progression and signs of repair or remodelling were then scored by indicating the proportion of normal subchondral bone, subchondral plate and joint space on an 11-point rating scale (range 0–100 with 10 unit increases). Inter- and intrareader reproducibility was studied using intraclass correlation coefficients (ICCs). Based on the within-variance of two readers, the smallest detectable change (SDC) was calculated and allowed identification of joints with changes above the SDC as ‘progressors’. Results Longitudinal inter-reader ICC scores rated well for all variables and the total score (ICC 0.86–0.93). To identify ‘real’ change over background noise, a change of at least 40 units on the total score (range 0–300) over 12 months (SDC 0–12:36.0), and 50 units over 6 months (SDC 0–6:47.6) had to be present. 60% of the 30 joints were identified as ‘progressors’ over 6 months compared with 33.3% with the classical anatomical scoring system, and 70% versus 56.6%, respectively, over 12 months. Conclusion GUSS, is a reliable method to score radiographic change over time in erosive IP OA and detects more progression over a shorter period of time than the classical scoring system. PMID:19948521

  6. Accuracy Improvement on the Measurement of Human-Joint Angles.

    PubMed

    Meng, Dai; Shoepe, Todd; Vejarano, Gustavo

    2016-03-01

    A measurement technique that decreases the root mean square error (RMSE) of measurements of human-joint angles using a personal wireless sensor network is reported. Its operation is based on virtual rotations of wireless sensors worn by the user, and it focuses on the arm, whose position is measured on 5 degree of freedom (DOF). The wireless sensors use inertial magnetic units that measure the alignment of the arm with the earth's gravity and magnetic fields. Due to the biomechanical properties of human tissue (e.g., skin's elasticity), the sensors' orientation is shifted, and this shift affects the accuracy of measurements. In the proposed technique, the change of orientation is first modeled from linear regressions of data collected from 15 participants at different arm positions. Then, out of eight body indices measured with dual-energy X-ray absorptiometry, the percentage of body fat is found to have the greatest correlation with the rate of change in sensors' orientation. This finding enables us to estimate the change in sensors' orientation from the user's body fat percentage. Finally, an algorithm virtually rotates the sensors using quaternion theory with the objective of reducing the error. The proposed technique is validated with experiments on five different participants. In the DOF, whose error decreased the most, the RMSE decreased from 2.20(°) to 0.87(°). This is an improvement of 60%, and in the DOF whose error decreased the least, the RMSE decreased from 1.64(°) to 1.37(°). This is an improvement of 16%. On an average, the RMSE improved by 44%. PMID:25622331

  7. Goniometrie evaluation of standing extension and maximum flexion joint angles of llamas and alpacas.

    PubMed

    Walters, Amy L; Semevolos, Stacy A; Baker, Rose E

    2016-09-01

    OBJECTIVE To determine and compare mean standing extension and maximum flexion angles of various joints in healthy adult alpacas and llamas, and determine the reliability of goniometric data within and between 2 observers for each joint of interest. SAMPLE 6 healthy adult llamas and 6 healthy adult alpacas. PROCEDURES The shoulder joint, elbow joint, carpal, and metacarpophalangeal (MCP) joints of the forelimbs and the hip joint, stifle joint, tarsal, and metatarsophalangeal (MTP) joints of the hind limbs were investigated. Each articulation was measured with a universal goniometer by 2 observers, who each obtained 2 measurements when each joint was maintained in standing extension and in maximal passive flexion. Two sample (unpaired) t tests were performed for comparisons of mean standing extension and maximum passive flexion angles between alpacas and llamas. Intraclass correlation coefficients were calculated for each articulation to assess interobserver and intra-observer reliability of measurements. RESULTS Llamas had larger mean standing extension angles than alpacas for the tarsal and elbow joint, but there were no significant differences between species for all other joints. For all joints, flexion measurements did not differ significantly between the 2 species. For most joints, the reliability of goniometric data between observers was good to excellent (intraclass correlation coefficients, 0.6 to 0.95) CONCLUSIONS AND CLINICAL RELEVANCE Except for the elbow joint and tarsus in extension, the angle of limb articulations during flexion and extension can be considered similar for alpacas and llamas. These measurements have relevance for veterinary surgeons when assessing joint mobility and conformation and determining appropriate angles for arthrodesis. PMID:27580112

  8. 98. 28'X40' original vellum, VariableAngle Launcher '32 INCH 'Y' JOINT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    98. 28'X40' original vellum, Variable-Angle Launcher '32 INCH 'Y' JOINT AND TRANSITION ASSEMBLY' drawn at 1 1/2'=1'-0'. (P.W. DWG. NO. 1785). - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  9. 99. 28'X40' original vellum, VariableAngle Launcher '32 INCH 'Y' JOINT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    99. 28'X40' original vellum, Variable-Angle Launcher '32 INCH 'Y' JOINT DETAILS drawn at 1 1/2'=1'-0' and 6'=1'-0'. (P.W. DWG. NO. 1786). - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  10. An Architecture for Measuring Joint Angles Using a Long Period Fiber Grating-Based Sensor

    PubMed Central

    Perez-Ramirez, Carlos A.; Almanza-Ojeda, Dora L.; Guerrero-Tavares, Jesus N.; Mendoza-Galindo, Francisco J.; Estudillo-Ayala, Julian M.; Ibarra-Manzano, Mario A.

    2014-01-01

    The implementation of signal filters in a real-time form requires a tradeoff between computation resources and the system performance. Therefore, taking advantage of low lag response and the reduced consumption of resources, in this article, the Recursive Least Square (RLS) algorithm is used to filter a signal acquired from a fiber-optics-based sensor. In particular, a Long-Period Fiber Grating (LPFG) sensor is used to measure the bending movement of a finger. After that, the Gaussian Mixture Model (GMM) technique allows us to classify the corresponding finger position along the motion range. For these measures to help in the development of an autonomous robotic hand, the proposed technique can be straightforwardly implemented on real time platforms such as Field Programmable Gate Array (FPGA) or Digital Signal Processors (DSP). Different angle measurements of the finger's motion are carried out by the prototype and a detailed analysis of the system performance is presented. PMID:25536002

  11. An architecture for measuring joint angles using a long period fiber grating-based sensor.

    PubMed

    Perez-Ramirez, Carlos A; Almanza-Ojeda, Dora L; Guerrero-Tavares, Jesus N; Mendoza-Galindo, Francisco J; Estudillo-Ayala, Julian M; Ibarra-Manzano, Mario A

    2014-01-01

    The implementation of signal filters in a real-time form requires a tradeoff between computation resources and the system performance. Therefore, taking advantage of low lag response and the reduced consumption of resources, in this article, the Recursive Least Square (RLS) algorithm is used to filter a signal acquired from a fiber-optics-based sensor. In particular, a Long-Period Fiber Grating (LPFG) sensor is used to measure the bending movement of a finger. After that, the Gaussian Mixture Model (GMM) technique allows us to classify the corresponding finger position along the motion range. For these measures to help in the development of an autonomous robotic hand, the proposed technique can be straightforwardly implemented on real time platforms such as Field Programmable Gate Array (FPGA) or Digital Signal Processors (DSP). Different angle measurements of the finger's motion are carried out by the prototype and a detailed analysis of the system performance is presented. PMID:25536002

  12. Abdominal muscle activity according to knee joint angle during sit-to-stand

    PubMed Central

    Eom, Juri; Rhee, Min-Hyung; Kim, Laurentius Jongsoon

    2016-01-01

    [Purpose] This study assessed the activity of the abdominal muscles according to the angle of the knee joints during sit-to-stand. [Subjects and Methods] Thirty healthy adult males participated in this study. Subjects initiated sit-to-stand at knee joint angles of 60°, 90°, or 120°. An electromyography system was used to measure the maximum voluntary isometric contraction of the rectus abdominis, external oblique, and internal oblique and transverse abdominis muscles. [Results] Percent contraction differed significantly among the three knee joint angles, most notably for the internal oblique and transverse abdominis muscles. [Conclusion] Wider knee joint angles more effectively activate the abdominal muscles, especially those in the deep abdomen, than do narrower angles. PMID:27390431

  13. The Effects of Sex, Joint Angle, and the Gastrocnemius Muscle on Passive Ankle Joint Complex Stiffness

    PubMed Central

    DeMont, Richard G.; Ryu, Keeho; Lephart, Scott M.

    2001-01-01

    Objective: To assess the effects of sex, joint angle, and the gastrocnemius muscle on passive ankle joint complex stiffness (JCS). Design and Setting: A repeated-measures design was employed using sex as a between-subjects factor and joint angle and inclusion of the gastrocnemius muscle as within-subject factors. All testing was conducted in a neuromuscular research laboratory. Subjects: Twelve female and 12 male healthy, physically active subjects between the ages of 18 and 30 years volunteered for participation in this study. The dominant leg was used for testing. No subjects had a history of lower extremity musculoskeletal injury or circulatory or neurologic disorders. Measurements: We determined passive ankle JCS by measuring resistance to passive dorsiflexion (5°·s−1) from 23° plantar flexion (PF) to 13° dorsiflexion (DF). Angular position and torque data were collected from a dynamometer under 2 conditions designed to include or reduce the contribution of the gastrocnemius muscle. Separate fourth-order polynomial equations relating angular position and torque were constructed for each trial. Stiffness values (Nm·degree−1) were calculated at 10° PF, neutral (NE), and 10° DF using the slope of the line at each respective position. Results: Significant condition-by-position and sex-by-position interactions and significant main effects for sex, position, and condition were revealed by a 3-way (sex-by-position, condition-by-position) analysis of variance. Post hoc analyses of the condition-by-position interaction revealed significantly higher stiffness values under the knee-straight condition compared with the knee-bent condition at both ankle NE and 10° DF. Within each condition, stiffness values at each position were significantly higher as the ankle moved into DF. Post hoc analysis of the sex-by-position interaction revealed significantly higher stiffness values at 10° DF in the male subjects. Post hoc analysis of the position main effect revealed

  14. Noninvasive imaging of hemoglobin concentration and oxygen saturation for detection of osteoarthritis in the finger joints using multispectral three-dimensional quantitative photoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Sun, Yao; Sobel, Eric; Jiang, Huabei

    2013-05-01

    We present quantitative imaging of hemoglobin concentration and oxygen saturation in in vivo finger joints and evaluate the feasibility of detecting osteoarthritis (OA) in the hand using three-dimensional (3D) multispectral quantitative photoacoustic tomography (3D qPAT). The results show that both the anatomical structures and quantitative chromophore concentrations (oxy-hemoglobin and deoxy-hemoglobin) of different joint tissues (hard phalanges and soft cartilage/synovial fluid between phalanges) can be imaged in vivo with the multispectral 3D qPAT. Enhanced hemoglobin concentrations and dropped oxygen saturations in osteoarthritic phalanges and soft joint tissues in joint cavities have been observed. This study indicates that the multispectral 3D qPAT is a promising approach to detect the angiogenesis and hypoxia associated with OA disease and a potential clinical tool for early OA detection in the finger joints.

  15. A three-dimensional finite element analysis of finger joint stresses in the MCP joint while performing common tasks.

    PubMed

    Butz, Kent D; Merrell, Greg; Nauman, Eric A

    2012-09-01

    The goal of this study was to develop a three-dimensional finite element model of the metacarpophalangeal (MCP) joint to characterize joint contact stresses incurred during common daily activities. The metacarpal and proximal phalanx were modeled using a COMSOL-based finite element analysis. Muscle forces determined from a static force analysis of two common activities (pen grip and carrying a weight) were applied to the simulation to characterize the surface stress distributions at the MCP joint. The finite element analysis predicted that stresses as high as 1.9 MPa, similar in magnitude to stresses experienced at the hip, may be experienced by the subchondral bone in the MCP joint. The internal structure and material properties of the phalanges were found to play a significant role in both the magnitude and distribution of stresses, but the dependence on cancellous bone modulus was not as severe as predicted by previous two dimensional models. PMID:23997746

  16. Mallet finger injuries-A new method to maintain distal interphalangeal joint extension.

    PubMed

    Mak, Lonita; Aitkens, Lorna D; Novak, Christine B

    2016-01-01

    Ensuring that distal interphalangeal joint extension is maintained is an important but challenging part of the treatment process. These authors describe a simple approach to ensuring distal interphalangeal joint extension for these patients. - VictoriaPriganc, PhD, OTR, CHT, CLT, Practice Forum Editor. PMID:27496991

  17. Quantitative three-dimensional photoacoustic tomography of the finger joints: an in vivo study

    NASA Astrophysics Data System (ADS)

    Sun, Yao; Sobel, Eric; Jiang, Huabei

    2009-11-01

    We present for the first time in vivo full three-dimensional (3-D) photoacoustic tomography (PAT) of the distal interphalangeal joint in a human subject. Both absorbed energy density and absorption coefficient images of the joint are quantitatively obtained using our finite-element-based photoacoustic image reconstruction algorithm coupled with the photon diffusion equation. The results show that major anatomical features in the joint along with the side arteries can be imaged with a 1-MHz transducer in a spherical scanning geometry. In addition, the cartilages associated with the joint can be quantitatively differentiated from the phalanx. This in vivo study suggests that the 3-D PAT method described has the potential to be used for early diagnosis of joint diseases such as osteoarthritis and rheumatoid arthritis.

  18. Joint-Angle Coordination Patterns Ensure Stabilization of a Body-Plus-Tool System in Point-to-Point Movements with a Rod

    PubMed Central

    Valk, Tim A.; Mouton, Leonora J.; Bongers, Raoul M.

    2016-01-01

    When performing a goal-directed action with a tool, it is generally assumed that the point of control of the action system is displaced from the hand to the tool, implying that body and tool function as one system. Studies of how actions with tools are performed have been limited to studying either end-effector kinematics or joint-angle coordination patterns. Because joint-angle coordination patterns affect end-effector kinematics, the current study examined them together, with the aim of revealing how body and tool function as one system. Seated participants made point-to-point movements with their index finger, and with rods of 10, 20, and 30 cm attached to their index finger. Start point and target were presented on a table in front of them, and in half of the conditions a participant displacement compensated for rod length. Results revealed that the kinematics of the rod's tip showed higher peak velocity, longer deceleration time, and more curvature with longer rods. End-effector movements were more curved in the horizontal plane when participants were not displaced. Joint-angle trajectories were similar across rod lengths when participants were displaced, whereas more extreme joint-angles were used with longer rods when participants were not displaced. Furthermore, in every condition the end-effector was stabilized to a similar extent; both variability in joint-angle coordination patterns that affected end-effector position and variability that did not affect end-effector position increased in a similar way vis-à-vis rod length. Moreover, the increase was higher in those conditions, in which participants were not displaced. This suggests that during tool use, body and tool are united in a single system so as to stabilize the end-effector kinematics in a similar way that is independent of tool length. In addition, the properties of the actual trajectory of the end-effector, as well as the actual joint-angles used, depend on the length of the tool and the

  19. Extrinsic versus intrinsic hand muscle dominance in finger flexion.

    PubMed

    Al-Sukaini, A; Singh, H P; Dias, J J

    2016-05-01

    This study aims to identify the patterns of dominance of extrinsic or intrinsic muscles in finger flexion during initiation of finger curl and mid-finger flexion. We recorded 82 hands of healthy individuals (18-74 years) while flexing their fingers and tracked the finger joint angles of the little finger using video motion tracking. A total of 57 hands (69.5%) were classified as extrinsic dominant, where the finger flexion was initiated and maintained at proximal interphalangeal and distal interphalangeal joints. A total of 25 (30.5%) were classified as intrinsic dominant, where the finger flexion was initiated and maintained at the metacarpophalangeal joint. The distribution of age, sex, dominance, handedness and body mass index was similar in the two groups. This knowledge may allow clinicians to develop more efficient rehabilitation regimes, since intrinsic dominant individuals would not initiate extrinsic muscle contraction till later in finger flexion, and might therefore be allowed limited early active motion. For extrinsic dominant individuals, by contrast, initial contraction of extrinsic muscles would place increased stress on the tendon repair site if early motion were permitted. PMID:26744509

  20. Hip rotation angle is associated with frontal plane knee joint mechanics during running.

    PubMed

    Sakaguchi, Masanori; Shimizu, Norifumi; Yanai, Toshimasa; Stefanyshyn, Darren J; Kawakami, Yasuo

    2015-02-01

    Inability to control lower extremity segments in the frontal and transverse planes resulting in large knee abduction angle and increased internal knee abduction impulse has been associated with patellofemoral pain (PFP). However, the influence of hip rotation angles on frontal plane knee joint kinematics and kinetics remains unclear. The purpose of this study was to explore how hip rotation angles are related to frontal plane knee joint kinematics and kinetics during running. Seventy runners participated in this study. Three-dimensional marker positions and ground reaction forces were recorded with an 8-camera motion analysis system and a force plate while subjects ran along a 25-m runway at a speed of 4m/s. Knee abduction, hip rotation and toe-out angles, frontal plane lever arm at the knee, internal knee abduction moment and impulse, ground reaction forces and the medio-lateral distance from the ankle joint center to the center of pressure (AJC-CoP) were quantified. The findings of this study indicate that greater hip external rotation angles were associated with greater toe-out angles, longer AJC-CoP distances, smaller internal knee abduction impulses with shorter frontal plane lever arms and greater knee abduction angles. Thus, there appears to exist a conflict between kinematic and kinetic risk factors of PFP, and hip external rotation angle may be a key factor to control frontal plane knee joint kinematics and kinetics. These results may help provide an appropriate manipulation and/or intervention on running style to reduce the risk of PFP. PMID:25572723

  1. Three-Fingered Robot Hand

    NASA Technical Reports Server (NTRS)

    Ruoff, C. F.; Salisbury, J. K.

    1984-01-01

    Mechanical joints and tendons resemble human hand. Robot hand has three "human-like" fingers. "Thumb" at top. Rounded tips of fingers covered with resilient material provides high friction for griping. Hand potential as prosthesis for humans.

  2. Feasibility study of semi-automated measurements of finger joint space widths.

    PubMed

    Pfeil, Alexander; Sommerfeld, Julia; Fröber, Rosemarie; Lehmann, Gabriele; Malich, Ansgar; Hansch, Andreas; Wolf, Gunter; Böttcher, Joachim

    2011-10-01

    The purpose of this study is to evaluate technical feasibility based on image capturing conditions (film-focus distance (FFD), film sensitivity, film brand, exposure level and tube voltage) that potentially alter radiographs and consequently may influence the semi-automated measurement of joint space distance (JSD) by computer-aided joint space analysis (CAJSA) in rheumatoid arthritis and osteoarthritis. The radiographs of a left hand (deceased man) were acquired under systematically changing image capturing conditions (exposure level: 4-8 mAs; FFD: 90-130 cm; film sensitivity: 200/400 and tube voltage: 40-52 kV with different image modalities: conventional radiographs, original digital radiographs, digital print-outs). All JSD-measurements were performed with the CAJSA-technology (Radiogrammetry Kit, Version 1.3.6; Sectra; Sweden) at the metacarpal-phalangeal articulation. JSD-analysis was not influenced by changes of FFD, exposure level, film sensitivity or film brand. JSD showed significant variation caused by tube voltage (conventional: CV = 1.913% for Agfa and CV = 2.448% for Kodak; digital: CV = 0.741% for Philips print-outs and CV = 0.620% with original digital images versus CV = 2.185% for Siemens print-outs and 0.951% with original digital images). Computer-aided joint space analysis for JSD-measurements is unaffected by the following image capturing parameters: film-focus distance, film sensitivity, film brand and exposure level. An influence of tube voltage was detected in a lesser extent for original digital images compared to the printed digital as well as conventional versions. Consequently, a standardized tube voltage is essential for accurate reproductions of CAJSA-measurements in rheumatoid arthritis and osteoarthritis. PMID:20401484

  3. Multi-fingered robotic hand

    NASA Technical Reports Server (NTRS)

    Ruoff, Carl F. (Inventor); Salisbury, Kenneth, Jr. (Inventor)

    1990-01-01

    A robotic hand is presented having a plurality of fingers, each having a plurality of joints pivotally connected one to the other. Actuators are connected at one end to an actuating and control mechanism mounted remotely from the hand and at the other end to the joints of the fingers for manipulating the fingers and passing externally of the robot manipulating arm in between the hand and the actuating and control mechanism. The fingers include pulleys to route the actuators within the fingers. Cable tension sensing structure mounted on a portion of the hand are disclosed, as is covering of the tip of each finger with a resilient and pliable friction enhancing surface.

  4. Lower Extremity Joint Angle Tracking with Wireless Ultrasonic Sensors during a Squat Exercise

    PubMed Central

    Qi, Yongbin; Soh, Cheong Boon; Gunawan, Erry; Low, Kay-Soon; Thomas, Rijil

    2015-01-01

    This paper presents an unrestrained measurement system based on a wearable wireless ultrasonic sensor network to track the lower extremity joint and trunk kinematics during a squat exercise with only one ultrasonic sensor attached to the trunk. The system consists of an ultrasound transmitter (mobile) and multiple receivers (anchors) whose positions are known. The proposed system measures the horizontal and vertical displacement, together with known joint constraints, to estimate joint flexion/extension angles using an inverse kinematic model based on the damped least-squares technique. The performance of the proposed ultrasonic measurement system was validated against a camera-based tracking system on eight healthy subjects performing a planar squat exercise. Joint angles estimated from the ultrasonic system showed a root mean square error (RMSE) of 2.85° ± 0.57° with the reference system. Statistical analysis indicated great agreements between these two systems with a Pearson's correlation coefficient (PCC) value larger than 0.99 for all joint angles' estimation. These results show that the proposed ultrasonic measurement system is useful for applications, such as rehabilitation and sports. PMID:25915589

  5. Quantification of inertial sensor-based 3D joint angle measurement accuracy using an instrumented gimbal.

    PubMed

    Brennan, A; Zhang, J; Deluzio, K; Li, Q

    2011-07-01

    This study quantified the accuracy of inertial sensors in 3D anatomical joint angle measurement with respect to an instrumented gimbal. The gimbal rotated about three axes and directly measured the angles in the ISB recommended knee joint coordinate system. Through the use of sensor attachment devices physically fixed to the gimbal, the joint angle estimation error due to sensor attachment (the inaccuracy of the sensor attachment matrix) was essentially eliminated, leaving only error due to the inertial sensors. The angle estimation error (RMSE) corresponding to the sensor was found to be 3.20° in flexion/extension, 3.42° in abduction/adduction and 2.88° in internal/external rotation. Bland-Altman means of maximum absolute value were -1.63° inflexion/extension, 3.22° in abduction/adduction and -2.61° in internal/external rotation. The magnitude of the errors reported in this study imply that even under ideal conditions irreproducible in human gait studies, inertial angle measurement will be subject to errors of a few degrees. Conversely, the reported errors are smaller than those reported previously in human gait studies, which suggest that the sensor attachment is also significant source of error in inertial gait measurement. The proposed apparatus and methodology could be used to quantify the performance of different sensor systems and orientation estimation algorithms, and to verify experimental protocols before human experimentation. PMID:21715167

  6. The effect of angle and moment of the hip and knee joint on iliotibial band hardness.

    PubMed

    Tateuchi, Hiroshige; Shiratori, Sakiko; Ichihashi, Noriaki

    2015-02-01

    Although several studies have described kinematic deviations such as excessive hip adduction in patients with iliotibial band (ITB) syndrome, the factors contributing to increased ITB hardness remains undetermined, owing to lack of direct in vivo measurement. The purpose of this study was to clarify the factors contributing to an increase in ITB hardness by comparing the ITB hardness between the conditions in which the angle, moment, and muscle activity of the hip and knee joint are changed. Sixteen healthy individuals performed the one-leg standing under five conditions in which the pelvic and trunk inclination were changed in the frontal plane. The shear elastic modulus in the ITB was measured as an indicator of the ITB hardness using shear wave elastography. The three-dimensional joint angle and external joint moment in the hip and knee joints, and muscle activities of the gluteus maximus, gluteus medius, tensor fasciae latae, and vastus lateralis, which anatomically connect to the ITB, were also measured. ITB hardness was significantly increased in the posture with pelvic and trunk inclination toward the contralateral side of the standing leg compared with that in all other conditions (increase of approximately 32% compared with that during normal one-leg standing). This posture increased both the hip adduction angle and external adduction moment at the hip and knee joint, although muscle activities were not increased. Our findings suggest that coexistence of an increased adduction moment at the hip and knee joints with an excessive hip adduction angle lead to an increase in ITB hardness. PMID:25542398

  7. Assessment of novel digital and smartphone goniometers for measurement of canine stifle joint angles.

    PubMed

    Freund, Kristin A; Kieves, Nina R; Hart, Juliette L; Foster, Sasha A; Jeffery, Unity; Duerr, Felix M

    2016-07-01

    OBJECTIVE To evaluate accuracy and reliability of 3 novel goniometers for measurement of canine stifle joint angles and compare the results with those obtained with a universal goniometer (UG). SAMPLE 8 pelvic limbs from 4 canine cadavers. PROCEDURES Each limb was secured to a wooden platform at 3 arbitrarily selected fixed stifle joint angles. Goniometry was performed with 2 smartphone-based applications (novel goniometers A and B), a digital goniometer (novel goniometer C), and a UG; 3 evaluators performed measurements in triplicate for each angle with each device. Results were compared with stifle joint angle measurements on radiographs (used as a gold standard). Accuracy was determined by calculation of bias and total error, coefficients of variation were calculated to estimate reliability, and strength of linear association between radiographic and goniometer measurements was assessed by calculation of correlation coefficients. RESULTS Mean coefficient of variation was lowest for the UG (4.88%), followed by novel goniometers B (7.37%), A (7.57%), and C (12.71%). Correlation with radiographic measurements was highest for the UG (r = 0.97), followed by novel goniometers B (0.93), A (0.90), and C (0.78). Constant bias was present for all devices except novel goniometer B. The UG and novel goniometer A had positive constant bias; novel goniometer C had negative constant bias. Total error at 50° and 100° angles was > 5% for all devices. CONCLUSIONS AND CLINICAL RELEVANCE None of the devices accurately represented radiographically measured stifle joint angles. Additional veterinary studies are indicated prior to the use of novel goniometers in dogs. PMID:27347828

  8. The effect of an active vibration stimulus according to different shoulder joint angles on functional reach and stability of the shoulder joint

    PubMed Central

    Kim, Eun-Kyung; Kim, Seong-Gil

    2016-01-01

    [Purpose] The purpose of this study was to analyze the effect of an active vibration stimulus exercise according to shoulder joint angles on functional reach and stability of the shoulder joint. [Subjects and Methods] Thirty healthy male students participated in this study. Upper limb length of each subject was measured to obtain normalized measurement values. The exercise groups were as follows: group I (n=10, shoulder joint angle of 90°), group II (n=10, shoulder joint angle of 130°), and group III (n=10, shoulder joint angle of 180°). After warm-up, an active vibration stimulus was applied to the subjects with a Flexi-Bar. The Functional Reach Test and Y-balance test were conducted for measurement of shoulder stability. [Results] Analysis of covariance was conducted with values before the intervention as covariates to analyze the differences among the groups in the two tests. There were significant differences among the groups. According to Bonferroni post hoc comparison, group I showed greater improvement than group III in the Functional Reach Test, and group II showed greater improvement than group I and group III in the Y-balance test. [Conclusion] The effect of the exercise with different shoulder joint angles revealed that the shoulder joint has a certain effective joint angle for its functionality and stability. In addition, application of an active vibration stimulus with a Flexi-Bar can be a very effective tool for improvement of functionality and stability of the shoulder joint. PMID:27134352

  9. Ankle Joint Angle and Lower Leg Musculotendinous Unit Responses to Cryotherapy.

    PubMed

    Akehi, Kazuma; Long, Blaine C; Warren, Aric J; Goad, Carla L

    2016-09-01

    Akehi, K, Long, BC, Warren, AJ, and Goad, CL. Ankle joint angle and lower leg musculotendinous unit responses to cryotherapy. J Strength Cond Res 30(9): 2482-2492, 2016-The use of cold application has been debated for its influence on joint range of motion (ROM) and stiffness. The purpose of this study was to determine whether a 30-minute ice bag application to the plantarflexor muscles or ankle influences passive ankle dorsiflexion ROM and lower leg musculotendinous stiffness (MTS). Thirty-five recreationally active college-aged individuals with no history of lower leg injury 6 months before data collection volunteered. On each testing day, we measured maximum passive ankle dorsiflexion ROM (°) and plantarflexor torque (N·m) on an isokinetic dynamometer to calculate the passive plantarflexor MTS (N·m per degree) at 4 joint angles before, during, and after a treatment. Surface electromyography amplitudes (μV), and skin surface and ambient air temperature (°C) were also measured. Subjects received an ice bag to the posterior lower leg, ankle joint, or nothing for 30 minutes in different days. Ice bag application to the lower leg and ankle did not influence passive ROM (F(12,396) = 0.67, p = 0.78). Passive torque increased after ice bag application to the lower leg (F(12,396) = 2.21, p = 0.011). Passive MTS at the initial joint angle increased after ice bag application to the lower leg (F(12,396) = 2.14, p = 0.014) but not at the other joint angles (p > 0.05). Surface electromyography amplitudes for gastrocnemius and soleus muscles increased after ice application to the lower leg (F(2,66) = 5.61, p = 0.006; F(12,396) = 3.60, p < 0.001). Ice bag application to the lower leg and ankle joint does not alter passive dorsiflexion ROM but increases passive ankle plantarflexor torque in addition to passive ankle plantarflexor MTS at the initial joint angle. PMID:26863585

  10. Mobile Phone-Based Joint Angle Measurement for Functional Assessment and Rehabilitation of Proprioception

    PubMed Central

    Mourcou, Quentin; Fleury, Anthony; Diot, Bruno; Franco, Céline; Vuillerme, Nicolas

    2015-01-01

    Assessment of joint functional and proprioceptive abilities is essential for balance, posture, and motor control rehabilitation. Joint functional ability refers to the capacity of movement of the joint. It may be evaluated thereby measuring the joint range of motion (ROM). Proprioception can be defined as the perception of the position and of the movement of various body parts in space. Its role is essential in sensorimotor control for movement acuity, joint stability, coordination, and balance. Its clinical evaluation is commonly based on the assessment of the joint position sense (JPS). Both ROM and JPS measurements require estimating angles through goniometer, scoliometer, laser-pointer, and bubble or digital inclinometer. With the arrival of Smartphones, these costly clinical tools tend to be replaced. Beyond evaluation, maintaining and/or improving joint functional and proprioceptive abilities by training with physical therapy is important for long-term management. This review aims to report Smartphone applications used for measuring and improving functional and proprioceptive abilities. It identifies that Smartphone applications are reliable for clinical measurements and are mainly used to assess ROM and JPS. However, there is lack of studies on Smartphone applications which can be used in an autonomous way to provide physical therapy exercises at home. PMID:26583101

  11. Mobile Phone-Based Joint Angle Measurement for Functional Assessment and Rehabilitation of Proprioception.

    PubMed

    Mourcou, Quentin; Fleury, Anthony; Diot, Bruno; Franco, Céline; Vuillerme, Nicolas

    2015-01-01

    Assessment of joint functional and proprioceptive abilities is essential for balance, posture, and motor control rehabilitation. Joint functional ability refers to the capacity of movement of the joint. It may be evaluated thereby measuring the joint range of motion (ROM). Proprioception can be defined as the perception of the position and of the movement of various body parts in space. Its role is essential in sensorimotor control for movement acuity, joint stability, coordination, and balance. Its clinical evaluation is commonly based on the assessment of the joint position sense (JPS). Both ROM and JPS measurements require estimating angles through goniometer, scoliometer, laser-pointer, and bubble or digital inclinometer. With the arrival of Smartphones, these costly clinical tools tend to be replaced. Beyond evaluation, maintaining and/or improving joint functional and proprioceptive abilities by training with physical therapy is important for long-term management. This review aims to report Smartphone applications used for measuring and improving functional and proprioceptive abilities. It identifies that Smartphone applications are reliable for clinical measurements and are mainly used to assess ROM and JPS. However, there is lack of studies on Smartphone applications which can be used in an autonomous way to provide physical therapy exercises at home. PMID:26583101

  12. Comparison of the tibial mechanical joint orientation angles in dogs with cranial cruciate ligament rupture

    PubMed Central

    Fuller, Mark C.; Kapatkin, Amy S.; Bruecker, Kenneth A.; Holsworth, Ian G.; Kass, Philip H.; Hayashi, Kei

    2014-01-01

    Use of the tibial mechanical joint orientation angles is now the standard of care for evaluating tibial deformities, although they have not been used to evaluate dogs with cranial cruciate ligament (CrCL) rupture. The objective of this study was to compare the tibial mechanical joint orientation angles and tibial plateau angle (TPA) between dogs with bilateral CrCL rupture (BR) and unilateral CrCL rupture with (UR-SR) and without subsequent contralateral CrCL rupture (UR-w/o-SR) as risk factors for subsequent contralateral CrCL rupture. Twenty dogs (21.7%) were classified as BR, 38 (41.3%) were classified as UR-SR, and 34 (37.0%) were classified as UR-w/o-SR. The tibial mechanical joint orientation angles and TPA, in the range studied (< 35°), were not statistically different for dogs with BR, UR-SR, and UR-w/o-SR, and were not significant risk factors for subsequent contralateral CrCL rupture. PMID:25082991

  13. No evidence hip joint angle modulates intrinsically produced stretch reflex in human hopping.

    PubMed

    Gibson, W; Campbell, A; Allison, G

    2013-09-01

    Motor output in activities such as walking and hopping is suggested to be mediated neurally by purported stretch reflex augmentation of muscle output. Reflex EMG activity during these tasks has been frequently investigated in the soleus muscle; with alterations in reflex amplitude being associated with changes in hip joint angle/phase of the gait cycle. Previous work has focussed on reflex activity induced by an artificial perturbation or by induction of H-reflexes. As such, it is currently unknown if stretch reflex activity induced intrinsically (as part of the task) is modulated by changes in hip joint angle. This study investigated whether hip joint angle modulated reflex EMG 'burst' activity during a hopping task performed on a custom-built partially reclined sleigh. Ten subjects participated; EMG and kinematic data (VICON motor capture system) was collected for each hop cycle. Participants completed 5 sets of 30s of self-paced hopping in (1) hip neutral and (2) hip 60° flexion conditions. There was no difference in EMG 'burst' activity or in sagittal plane kinematics (knee/ankle) in the hopping task between the two conditions. The results indicate that during a functional task such as hopping, changes in hip angle do not alter the stretch reflex-like activity associated with landing. PMID:23791780

  14. A literature review on optimum and preferred joint angles in automotive sitting posture.

    PubMed

    Schmidt, Susanne; Amereller, Maximilian; Franz, Matthias; Kaiser, Ralf; Schwirtz, Ansgar

    2014-03-01

    In this study, a survey of the scientific literature in the field of optimum and preferred human joint angles in automotive sitting posture was conducted by referring to thirty different sources published between 1940 and today. The strategy was to use only sources with numerical angle data in combination with keywords. The aim of the research was to detect commonly used joint angles in interior car design. The main analysis was on data measurement, usability and comparability of the different studies. In addition, the focus was on the reasons for the differently described results. It was found that there is still a lack of information in methodology and description of background. Due to these reasons published data is not always usable to design a modern ergonomic car environment. As a main result of our literature analysis we suggest undertaking further research in the field of biomechanics and ergonomics to work out scientific based and objectively determined "optimum" joint angles in automotive sitting position. PMID:23664245

  15. The Effect of Gap Angle on Tensile Strength of Preceramic Base Metal Solder Joints

    PubMed Central

    Fattahi, Farnaz; Hashemi Ardakani, Zahra; Hashemi Ardakani, Maryam

    2015-01-01

    Statement of the Problem Soldering is a process commonly used in fabricating dental prosthesis. Since most soldered prosthesis fail at the solder joints; the joint strength is of utmost importance. Purpose The purpose of this study was to evaluate the effect of gap angle on the tensile strength of base metal solder joints. Materials and Method A total number of 40 Ni-Cr samples were fabricated according to ADA/ISO 9693 specifications for tensile test. Samples were cut at the midpoint of the bar, and were placed at the considered angles by employing an explicitly designed device. They were divided into 4 groups regarding the gap angle; Group C (control group) with parallel gap on steady distance of 0.2mm, Group 1: 10°, Group 2: 20°, and Group3: 30° gap angles. When soldered, the specimens were all tested for tensile strength using a universal testing machine at a cross-head speed of 0.5 mm/min with a preload of 10N. Kruskal-Wallis H test was used to compare tensile strength among the groups (p< 0.05). Results The mean tensile strength values obtained from the study groups were respectively 307.84, 391.50, 365.18, and 368.86 MPa. The tensile strength was not statistically different among the four groups in general (p≤ 0.490). Conclusion Making the gap angular at the solder joints and the subsequent unsteady increase of the gap distance would not change the tensile strength of the joint. PMID:26636118

  16. A proposal for a new definition of the axial rotation angle of the shoulder joint.

    PubMed

    Masuda, Tadashi; Ishida, Akimasa; Cao, Lili; Morita, Sadao

    2008-02-01

    The Euler/Cardan angles are commonly used to define the motions of the upper arm with respect to the trunk. This definition, however, has a problem in that the angles of both the horizontal flexion/extension and the axial rotation of the shoulder joint become unstable at the gimbal-lock positions. In this paper, a new definition of the axial rotation angle was proposed. The proposed angle was stable over the entire range of the shoulder motion. With the new definition, the neutral position of the axial rotation agreed with that in the conventional anatomy. The advantage of the new definition was demonstrated by measuring actual complex motions of the shoulder with a three-dimensional motion capture system. PMID:17070702

  17. Modeling of 3-D Object Manipulation by Multi-Joint Robot Fingers under Non-Holonomic Constraints and Stable Blind Grasping

    NASA Astrophysics Data System (ADS)

    Arimoto, Suguru; Yoshida, Morio; Bae, Ji-Hun

    This paper derives a mathematical model that expresses motion of a pair of multi-joint robot fingers with hemi-spherical rigid ends grasping and manipulating a 3-D rigid object with parallel flat surfaces. Rolling contacts arising between finger-ends and object surfaces are taken into consideration and modeled as Pfaffian constraints from which constraint forces emerge tangentially to the object surfaces. Another noteworthy difference of modeling of motion of a 3-D object from that of a 2-D object is that the instantaneous axis of rotation of the object is fixed in the 2-D case but that is time-varying in the 3-D case. A further difficulty that has prevented us to model 3-D physical interactions between a pair of fingers and a rigid object lies in the problem of treating spinning motion that may arise around the opposing axis from a contact point between one finger-end with one side of the object to another contact point. This paper shows that, once such spinning motion stops as the object mass center approaches just beneath the opposition axis, then this cease of spinning evokes a further nonholonomic constraint. Hence, the multi-body dynamics of the overall fingers-object system is subject to non-holonomic constraints concerning a 3-D orthogonal matrix expressing three mutually orthogonal unit vectors fixed at the object together with an extra non-holonomic constraint that the instantaneous axis of rotation of the object is always orthogonal to the opposing axis. It is shown that Lagrange's equation of motion of the overall system can be derived without violating the causality that governs the non-holonomic constraints. This immediately suggests possible construction of a numerical simulator of multi-body dynamics that can express motion of the fingers and object physically interactive to each other. By referring to the fact that human grasp an object in the form of precision prehension dynamically and stably by using opposable force between the thumb and another

  18. PARALIND-based blind joint angle and delay estimation for multipath signals with uniform linear array

    NASA Astrophysics Data System (ADS)

    Liu, Xu; Guang, Liang; Yang, Longxiang; Zhu, Hongbo

    2012-12-01

    A novel joint angle and delay estimation (JADE) algorithm for multipath signals, based on the PARAllel profiles with LINear Dependencies (PARALIND) model, is proposed. Capitalizing on the structure property of Vandermonde matrices, PARALIND model is proved to be unique. Angle and delay of multiple rays of sources can be estimated by PARALIND decomposition and an ESPRIT-like shift-invariance technique. Simulation results show that the proposed algorithm outperforms the traditional JADE algorithm. It can automatically distinguish the estimated parameters between sources, and still be available when the number of rays is larger than the number of receiving antennae.

  19. Assessment of Workspace Attributes Under Simulated Index Finger Proximal Interphalangeal Arthrodesis.

    PubMed

    Arauz, Paul G; Sisto, Sue A; Kao, Imin

    2016-05-01

    This article presented an assessment of quantitative measures of workspace (WS) attributes under simulated proximal interphalangeal (PIP) joint arthrodesis of the index finger. Seven healthy subjects were tested with the PIP joint unconstrained (UC) and constrained to selected angles using a motion analysis system. A model of the constrained finger was developed in order to address the impact of the inclusion of prescribed joint arthrodesis angles on WS attributes. Model parameters were obtained from system identification experiments involving flexion-extension (FE) movements of the UC and constrained finger. The data of experimental FE movements of the constrained finger were used to generate the two-dimensional (2D) WS boundaries and to validate the model. A weighted criterion was formulated to define an optimal constraint angle among several system parameters. Results indicated that a PIP joint immobilization angle of 40-50 deg of flexion maximized the 2D WS. The analysis of the aspect ratio of the 2D WS indicated that the WS was more evenly distributed as the imposed PIP joint constraint angle increased. With the imposed PIP joint constraint angles of 30 deg, 40 deg, 50 deg, and 60 deg of flexion, the normalized maximum distance of fingertip reach was reduced by approximately 3%, 4%, 7%, and 9%, respectively. PMID:26974649

  20. Mesofluidic controlled robotic or prosthetic finger

    SciTech Connect

    Lind, Randall F; Jansen, John F; Love, Lonnie J

    2013-11-19

    A mesofluidic powered robotic and/or prosthetic finger joint includes a first finger section having at least one mesofluidic actuator in fluid communication with a first actuator, a second mesofluidic actuator in fluid communication with a second actuator and a second prosthetic finger section pivotally connected to the first finger section by a joint pivot, wherein the first actuator pivotally cooperates with the second finger to provide a first mechanical advantage relative to the joint point and wherein the second actuator pivotally cooperates with the second finger section to provide a second mechanical advantage relative to the joint point.

  1. Human Joint Angle Estimation with Inertial Sensors and Validation with A Robot Arm.

    PubMed

    El-Gohary, Mahmoud; McNames, James

    2015-07-01

    Traditionally, human movement has been captured primarily by motion capture systems. These systems are costly, require fixed cameras in a controlled environment, and suffer from occlusion. Recently, the availability of low-cost wearable inertial sensors containing accelerometers, gyroscopes, and magnetometers have provided an alternative means to overcome the limitations of motion capture systems. Wearable inertial sensors can be used anywhere, cannot be occluded, and are low cost. Several groups have described algorithms for tracking human joint angles. We previously described a novel approach based on a kinematic arm model and the Unscented Kalman Filter (UKF). Our proposed method used a minimal sensor configuration with one sensor on each segment. This paper reports significant improvements in both the algorithm and the assessment. The new model incorporates gyroscope and accelerometer random drift models, imposes physical constraints on the range of motion for each joint, and uses zero-velocity updates to mitigate the effect of sensor drift. A high-precision industrial robot arm precisely quantifies the performance of the tracker during slow, normal, and fast movements over continuous 15-min recording durations. The agreement between the estimated angles from our algorithm and the high-precision robot arm reference was excellent. On average, the tracker attained an RMS angle error of about 3(°) for all six angles. The UKF performed slightly better than the more common Extended Kalman Filter. PMID:25700438

  2. Morphometric assessment of the canine hip joint using the acetabular angle of retrotorsion.

    PubMed

    Doskarova, B; Kyllar, M; Paral, V

    2010-01-01

    Morphometric assessment of the canine hip joint using acetabular angle of retrotorsion was used in this study. The aim of our study was to compare the acetabular angle of retrotorsion (AAR) with values of the Norberg angle (NA) and the hip score (HS) in the Leonberger dog breed and to determine the cut-off point of AAR that distinguish between normal and dysplastic hip status on the basis of Fédération Cynologique Internationale (FCI) hip evaluation. Retrospective analysis of NA and AAR was measured from standard ventrodorsal pelvic radiographs with extended femurs in 387 Leonberger dogs (141 males and 246 females) from 18 to 63 months of age, which were then divided into five age-groups. Through analysis of these radiographs, it was determined that the cut-off point for NA was 105°, AAR was 15°, and the acetabular angle of retrotorsion was positively correlated with Norberg angle and negatively correlated with hip score. The results of our study indicate that the acetabular angle of retrotorsion may represent a reliable morphometric assessment tool in evaluating acetabular cup conformation, and values of AAR may help to assess the FCI grade of canine hip dysplasia. PMID:20740259

  3. Muscle and reflex changes with varying joint angle in hemiparetic stroke

    PubMed Central

    Mirbagheri, Mehdi M; Alibiglou, Laila; Thajchayapong, Montakan; Rymer, William Z

    2008-01-01

    Background Despite intensive investigation, the origins of the neuromuscular abnormalities associated with spasticity are not well understood. In particular, the mechanical properties induced by stretch reflex activity have been especially difficult to study because of a lack of accurate tools separating reflex torque from torque generated by musculo-tendinous structures. The present study addresses this deficit by characterizing the contribution of neural and muscular components to the abnormally high stiffness of the spastic joint. Methods Using system identification techniques, we characterized the neuromuscular abnormalities associated with spasticity of ankle muscles in chronic hemiparetic stroke survivors. In particular, we systematically tracked changes in muscle mechanical properties and in stretch reflex activity during changes in ankle joint angle. Modulation of mechanical properties was assessed by applying perturbations at different initial angles, over the entire range of motion (ROM). Experiments were performed on both paretic and non-paretic sides of stroke survivors, and in healthy controls. Results Both reflex and intrinsic muscle stiffnesses were significantly greater in the spastic/paretic ankle than on the non-paretic side, and these changes were strongly position dependent. The major reflex contributions were observed over the central portion of the angular range, while the intrinsic contributions were most pronounced with the ankle in the dorsiflexed position. Conclusion In spastic ankle muscles, the abnormalities in intrinsic and reflex components of joint torque varied systematically with changing position over the full angular range of motion, indicating that clinical perceptions of increased tone may have quite different origins depending upon the angle where the tests are initiated. Furthermore, reflex stiffness was considerably larger in the non-paretic limb of stroke patients than in healthy control subjects, suggesting that the non

  4. INDIVIDUAL OPTIMAL FREQUENCY IN WHOLE BODY VIBRATION: EFFECT OF PROTOCOL, JOINT ANGLE AND FATIGUING EXERCISE.

    PubMed

    Carlucci, Flaminia; Felici, Francesco; Piccinini, Alberto; Haxhi, Jonida; Sacchetti, Massimo

    2013-04-12

    Recent studies have shown the importance of individualizing the vibration intervention in order to produce greater effects on the neuromuscular system in less time. The purpose of this study was to assess theindividualoptimalvibration frequency (O.V.F.)corresponding to the highestmuscle activation (RMSmax) duringvibrationat differentfrequencies, comparing different protocols. Twenty-nine university students underwent 3 Continuous (C) and 2 Random (R) different vibrating protocols, maintaining a squat position on a vibration platform. The C protocol lasted 50 seconds and involved the succession of ascending frequencies from 20 to 55 Hz, every 5 seconds. The same protocol was performed twice, having the knee angle at 120° (C) and 90° (C90), in order to assess the effect of joint angle, and after a fatiguing squatting exercise (CF) to evaluate the influence of fatigue on O.V.F. assessment. In therandomprotocols vibration time was 20 seconds with a 2-minute (R2) and a 4-minute (R4) pauses between tested frequencies. Muscle activation and O.V.F. values did not differ significantly in the C, R2 and R4 protocols. RMSmax was higher in C90 (p< 0.001) and in CF (p = 0.04) compared to the Cprotocol. Joint angle and fatiguing exercise had no effect on optimalvibration frequency. In conclusion, the shorter C protocol produced similar myoelectrical activity in the R2 and the R4 protocols and therefore could be equally valid in identifying the O.V.F. with considerable time efficiency. Knee joint angle and fatiguing exercise had an effect on sEMG response during vibration but did not affect significantly O.V.F. identification. PMID:23588483

  5. Use of dual Euler angles to quantify the three-dimensional joint motion and its application to the ankle joint complex.

    PubMed

    Ying, Ning; Kim, Wangdo

    2002-12-01

    This paper presents a modified Euler angles method, dual Euler angles approach, to describe general spatial human joint motions. In dual Euler angles approach, the three-dimensional joint motion is considered as three successive screw motions with respect to the axes of the moving segment coordinate system; accordingly, the screw motion displacements are represented by dual Euler angles. The algorithm for calculating dual Euler angles from coordinates of markers on the moving segment is also provided in this study. As an example, the proposed method is applied to describe motions of ankle joint complex during dorsiflexion-plantarflexion. A Flock of Birds electromagnetic tracking device (FOB) was used to measure joint motion in vivo. Preliminary accuracy tests on a gimbal structure demonstrate that the mean errors of dual Euler angles evaluated by using source data from FOB are less than 1 degrees for rotations and 1mm for translations, respectively. Based on the pilot study, FOB is feasible for quantifying human joint motions using dual Euler angles approach. PMID:12445618

  6. Joint mean angle of arrival, angular and Doppler spreads estimation in macrocell environments

    NASA Astrophysics Data System (ADS)

    Rejeb, Nessrine Ben; Bousnina, Inès; Ben Salah, Mohamed Bassem; Samet, Abdelaziz

    2014-12-01

    In this paper, we propose a new low-complexity joint estimator of the mean angle of arrival (AoA), the angular spread (AS), and the maximum Doppler spread (DS) for single-input multiple-output (SIMO) wireless channel configurations in a macrocell environment. The non-line-of-sight (NLOS) case is considered. The space-time correlation matrix is used to jointly estimate the three parameters. Closed-form expressions are developed for the desired parameters using the modules and the phases of the cross-correlation coefficients. Simulation results show that our approach offers a better tradeoff between computational complexity and accuracy than the most recent estimators in the literature.

  7. A portable system for collecting anatomical joint angles during stair ascent: a comparison with an optical tracking device

    PubMed Central

    Bergmann, Jeroen HM; Mayagoitia, Ruth E; Smith, Ian CH

    2009-01-01

    Background Assessments of stair climbing in real-life situations using an optical tracking system are lacking, as it is difficult to adapt the system for use in and around full flights of stairs. Alternatively, a portable system that consists of inertial measurement units (IMUs) can be used to collect anatomical joint angles during stair ascent. The purpose of this study was to compare the anatomical joint angles obtained by IMUs to those calculated from position data of an optical tracking device. Methods Anatomical joint angles of the thigh, knee and ankle, obtained using IMUs and an optical tracking device, were compared for fourteen healthy subjects. Joint kinematics obtained with the two measurement devices were evaluated by calculating the root mean square error (RMSE) and by calculating a two-tailed Pearson product-moment correlation coefficient (r) between the two signals. Results Strong mean correlations (range 0.93 to 0.99) were found for the angles between the two measurement devices, as well as an average root mean square error (RMSE) of 4 degrees over all the joint angles, showing that the IMUs are a satisfactory system for measuring anatomical joint angles. Conclusion These highly portable body-worn inertial sensors can be used by clinicians and researchers alike, to accurately collect data during stair climbing in complex real-life situations. PMID:19389238

  8. Impact of decline-board squat exercises and knee joint angles on the muscle activity of the lower limbs

    PubMed Central

    Lee, Daehee; Lee, Sangyong; Park, Jungseo

    2015-01-01

    [Purpose] This study aims to investigate how squat exercises on a decline board and how the knee joint angles affect the muscle activity of the lower limbs. [Subjects] The subjects were 26 normal adults. [Methods] A Tumble Forms wedge device was used as the decline board, and the knee joint angles were measured with a goniometer. To examine the muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior of the lower limbs, a comparison analysis with electromyography was conducted. [Results] The muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior increased with increased knee joint angles, both for squat exercises on the decline board and on a flat floor. When the knee joint angle was 45°, 60°, and 90°, the muscle activity of the rectus femoris was significantly higher and that of the tibialis anterior was significantly lower during squat exercises on the decline board than on the flat floor. When the knee joint angle was 90°, the muscle activity of the gastrocnemius lateralis was significantly lower. [Conclusion] Squat exercises on a decline board are an effective intervention to increase the muscle activity of the rectus femoris with increased knee joint angles. PMID:26357447

  9. Maximum voluntary joint torque as a function of joint angle and angular velocity: model development and application to the lower limb.

    PubMed

    Anderson, Dennis E; Madigan, Michael L; Nussbaum, Maury A

    2007-01-01

    Measurements of human strength can be important during analyses of physical activities. Such measurements have often taken the form of the maximum voluntary torque at a single joint angle and angular velocity. However, the available strength varies substantially with joint position and velocity. When examining dynamic activities, strength measurements should account for these variations. A model is presented of maximum voluntary joint torque as a function of joint angle and angular velocity. The model is based on well-known physiological relationships between muscle force and length and between muscle force and velocity and was tested by fitting it to maximum voluntary joint torque data from six different exertions in the lower limb. Isometric, concentric and eccentric maximum voluntary contractions were collected during hip extension, hip flexion, knee extension, knee flexion, ankle plantar flexion and dorsiflexion. Model parameters are reported for each of these exertion directions by gender and age group. This model provides an efficient method by which strength variations with joint angle and angular velocity may be incorporated into comparisons between joint torques calculated by inverse dynamics and the maximum available joint torques. PMID:17485097

  10. Joint space aspect reconstruction of wide-angle SAR exploiting sparsity

    NASA Astrophysics Data System (ADS)

    Stojanovic, Ivana; Cetin, Mujdat; Karl, William C.

    2008-04-01

    In this paper we present an algorithm for wide-angle synthetic aperture radar (SAR) image formation. Reconstruction of wide-angle SAR holds a promise of higher resolution and better information about a scene, but it also poses a number of challenges when compared to the traditional narrow-angle SAR. Most prominently, the isotropic point scattering model is no longer valid. We present an algorithm capable of producing high resolution reflectivity maps in both space and aspect, thus accounting for the anisotropic scattering behavior of targets. We pose the problem as a non-parametric three-dimensional inversion problem, with two constraints: magnitudes of the backscattered power are highly correlated across closely spaced look angles and the backscattered power originates from a small set of point scatterers. This approach considers jointly all scatterers in the scene across all azimuths, and exploits the sparsity of the underlying scattering field. We implement the algorithm and present reconstruction results on realistic data obtained from the XPatch Backhoe dataset.

  11. Variability and similarity of gait as evaluated by joint angles: implications for forensic gait analysis.

    PubMed

    Yang, Sylvia X M; Larsen, Peter K; Alkjær, Tine; Simonsen, Erik B; Lynnerup, Niels

    2014-03-01

    Closed-circuit television (CCTV) footage is used in criminal investigations to compare perpetrators with suspects. Usually, incomplete gait cycles are collected, making evidential gait analysis challenging. This study aimed to analyze the discriminatory power of joint angles throughout a gait cycle. Six sets from 12 men were collected. For each man, a variability range VR (mean ± 1SD) of a specific joint angle at a specific time point (a gait cycle was 100 time points) was calculated. In turn, each individual was compared with the 11 others, and whenever 1 of these 11 had a value within this individual’s VR, it counted as positive. By adding the positives throughout the gait cycle, we created simple bar graphs; tall bars indicated a small discriminatory power, short bars indicated a larger one. The highest discriminatory power was at time points 60–80 in the gait cycle. We show how our data can assess gait data from an actual case. PMID:24745080

  12. Joint image formation and anisotropy characterization in wide-angle SAR

    NASA Astrophysics Data System (ADS)

    Varshney, Kush R.; Çetin, Müjdat; Fisher, John W., III; Willsky, Alan S.

    2006-05-01

    We consider the problem of jointly forming images and characterizing anisotropy from wide-angle synthetic aperture radar (SAR) measurements. Conventional SAR image formation techniques assume isotropic scattering, which is not valid with wide-angle apertures. We present a method based on a sparse representation of aspect-dependent scattering with an overcomplete basis composed of basis vectors with varying levels of angular persistence. Solved as an inverse problem, the result is a complex-valued, aspect-dependent response for each spatial location in a scene. Our non-parametric approach does not suffer from reduced cross-range resolution inherent in subaperture methods and considers all point scatterers in a scene jointly. The choice of the overcomplete basis set incorporates prior knowledge of aspect-dependent scattering, but the method is flexible enough to admit solutions that may not match a family of parametric functions. We enforce sparsity through regularization based on the l k-norm, k < 1. This formulation leads to an optimization problem that is solved through a robust quasi-Newton method. We also develop a graph-structured interpretation of the overcomplete basis leading towards approximate algorithms using guided depth-first search with appropriate stopping conditions and search heuristics. We present experimental results on synthetic scenes and the backhoe public release dataset.

  13. An evaluation of the spring finger solder joints on SA1358-10 and SA2052-4 connector assemblies (MC3617,W87).

    SciTech Connect

    Kilgo, Alice C.; Vianco, Paul Thomas; Hlava, Paul Frank; Zender, Gary L.

    2006-08-01

    The SA1358-10 and SA2052-4 circular JT Type plug connectors are used on a number of nuclear weapons and Joint Test Assembly (JTA) systems. Prototype units were evaluated for the following specific defects associated with the 95Sn-5Sb (Sn-Sb, wt.%) solder joint used to attach the beryllium-copper (BeCu) spring fingers to the aluminum (Al) connector shell: (1) extended cracking within the fillet; (2) remelting of the solder joint during the follow-on, soldering step that attached the EMR adapter ring to the connector shell (and/or soldering the EMR shell to the adapter ring) that used the lower melting temperature 63Sn-37Pb (Sn-Pb) alloy; and (3) spalling of the Cd (Cr) layer overplating layer from the fillet surface. Several pedigrees of connectors were evaluated, which represented older fielded units as well as those assemblies that were recently constructed at Kansas City Plant. The solder joints were evaluated that were in place on connectors made with the current soldering process as well as an alternative induction soldering process for attaching the EMR adapter ring to the shell. Very similar observations were made, which crossed the different pedigrees of parts and processes. The extent of cracking in the top side fillets varied between the different connector samples and likely the EMR adapter ring to the shell. Very similar observations were made, which crossed the different pedigrees of parts and processes. The extent of cracking in the top side fillets varied between the different connector samples and likely reflected the different extents to which the connector was mated to its counterpart assembly. In all cases, the spring finger solder joints on the SA1358-10 connectors were remelted as a result of the subsequent EMR adapter ring attachment process. Spalling of the Cd (Cr) overplating layer was also observed for these connectors, which was a consequence of the remelting activity. On the other hand, the SA2052-4 connector did not exhibit evidence of

  14. Hip and knee joints are more stabilized than driven during the stance phase of gait: an analysis of the 3D angle between joint moment and joint angular velocity.

    PubMed

    Dumas, R; Cheze, L

    2008-08-01

    Joint power is commonly used in orthopaedics, ergonomics or sports analysis but its clinical interpretation remains controversial. Some basic principles on muscle actions and energy transfer have been proposed in 2D. The decomposition of power on 3 axes, although questionable, allows the same analysis in 3D. However, these basic principles have been widely criticized, mainly because bi-articular muscles must be considered. This requires a more complex computation in order to determine how the individual muscle force contributes to drive the joint. Conversely, with simple 3D inverse dynamics, the analysis of both joint moment and angular velocity directions is essential to clarify when the joint moment can contribute or not to drive the joint. The present study evaluates the 3D angle between the joint moment and the joint angular velocity and investigates when the hip, knee and ankle joints are predominantly driven (angle close to 0 degrees and 180 degrees ) or stabilized (angle close to 90 degrees ) during gait. The 3D angle curves show that the three joints are never fully but only partially driven and that the hip and knee joints are mainly stabilized during the stance phase. The notion of stabilization should be further investigated, especially for subjects with motion disorders or prostheses. PMID:18206375

  15. Robotic Finger Assembly

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Bridgwater, Lyndon (Inventor); Diftler, Myron A. (Inventor); Linn, Douglas M. (Inventor); Platt, Robert (Inventor); Hargrave, Brian (Inventor); Askew, Scott R. (Inventor); Valvo, Michael C. (Inventor)

    2013-01-01

    A robotic hand includes a finger with first, second, and third phalanges. A first joint rotatably connects the first phalange to a base structure. A second joint rotatably connects the first phalange to the second phalange. A third joint rotatably connects the third phalange to the second phalange. The second joint and the third joint are kinematically linked such that the position of the third phalange with respect to the second phalange is determined by the position of the second phalange with respect to the first phalange.

  16. Robotic Finger Assembly

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Bridgwater, Lyndon (Inventor); Diftler, Myron A. (Inventor); Linn, Douglas Martin (Inventor); Platt, Robert J., Jr. (Inventor); Hargrave, Brian (Inventor); Askew, Scott R. (Inventor); Valvo, Michael C. (Inventor)

    2014-01-01

    A robotic hand includes a finger with first, second, and third phalanges. A first joint rotatably connects the first phalange to a base structure. A second joint rotatably connects the first phalange to the second phalange. A third joint rotatably connects the third phalange to the second phalange. The second joint and the third joint are kinematically linked such that the position of the third phalange with respect to the second phalange is determined by the position of the second phalange with respect to the first phalange.

  17. EVALUATION OF THE INTERMETATARSAL ANGLE AFTER THE ARTHRODESIS OF THE FIRST METATARSOPHALANGEAL JOINT FOR TREATMENT OF THE HALLUX VALGUS

    PubMed Central

    Costa, Marco Túlio; Neto, Douglas Lobato Lopes; Kojima, Fábio Henrique; Ferreira, Ricardo Cardenuto

    2015-01-01

    Objective: To evaluate the correction of the intermetatarsal angle after arthrodesis of the metatarsophalangeal joint of the hallux. We believe that varus deformity of the first metatarsal can be corrected after arthrodesis of the first metatarsophalangeal joint, without the need for proximal osteotomy. Methods: Forty-three feet of patients who had undergone arthrodesis of the first metatarsophalangeal joint between May 1997 and October 2009 were retrospectively analyzed by means of radiographs. The mean length of follow-up was 58 months. Measurements on the metatarsophalangeal angle, intermetatarsal angle and sesamoid dislocation were made using radiographs made before, immediately after and later on after the operation. Results: The mean metatarsophalangeal angle was 37.6 degrees preoperatively, 12.8 degrees immediately after the operation and 16.4 degrees later on after the operation. The mean intermetatarsal angle was 16 degrees preoperatively, 10 degrees immediately after the operation and 10.2 degrees later on after the operation. Regarding sesamoid dislocation, preoperative radiographs showed most feet to be classified as G3; immediately after the operation, most were classified as G2; and later on after the operation, most were G1. Conclusion: The intermetatarsal angle and sesamoid dislocation improved with arthrodesis of the first metatarsophalangeal joint, without the need for osteotomy at the base of the first metatarsal. PMID:27042648

  18. Finger pain

    MedlinePlus

    Pain - finger ... Nearly everyone has had finger pain at some time. You may have: Tenderness Burning Stiffness Numbness Tingling Coldness Swelling Change in skin color Redness Many conditions, such ...

  19. Design and characterization of a wearable macrobending fiber optic sensor for human joint angle determination

    NASA Astrophysics Data System (ADS)

    Silva, Ana S.; Catarino, André; Correia, Miguel V.; Frazão, Orlando

    2013-12-01

    The work presented here describes the development and characterization of intensity fiber optic sensor integrated in a specifically designed piece of garment to measure elbow flexion. The sensing head is based on macrobending incorporated in the garment, and the increase of curvature number was studied in order to investigate which scheme provided a good result in terms of sensitivity and repeatability. Results showed the configuration that assured a higher sensitivity (0.644 dBm/deg) and better repeatability was the one with four loops. Ultimately, this sensor can be used for rehabilitation purposes to monitor human joint angles, namely, elbow flexion on stroke survivors while performing the reach functional task, which is the most common upper-limb human gesture.

  20. Detecting Elementary Arm Movements by Tracking Upper Limb Joint Angles With MARG Sensors.

    PubMed

    Mazomenos, Evangelos B; Biswas, Dwaipayan; Cranny, Andy; Rajan, Amal; Maharatna, Koushik; Achner, Josy; Klemke, Jasmin; Jobges, Michael; Ortmann, Steffen; Langendorfer, Peter

    2016-07-01

    This paper reports an algorithm for the detection of three elementary upper limb movements, i.e., reach and retrieve, bend the arm at the elbow and rotation of the arm about the long axis. We employ two MARG sensors, attached at the elbow and wrist, from which the kinematic properties (joint angles, position) of the upper arm and forearm are calculated through data fusion using a quaternion-based gradient-descent method and a two-link model of the upper limb. By studying the kinematic patterns of the three movements on a small dataset, we derive discriminative features that are indicative of each movement; these are then used to formulate the proposed detection algorithm. Our novel approach of employing the joint angles and position to discriminate the three fundamental movements was evaluated in a series of experiments with 22 volunteers who participated in the study: 18 healthy subjects and four stroke survivors. In a controlled experiment, each volunteer was instructed to perform each movement a number of times. This was complimented by a seminaturalistic experiment where the volunteers performed the same movements as subtasks of an activity that emulated the preparation of a cup of tea. In the stroke survivors group, the overall detection accuracy for all three movements was 93.75% and 83.00%, for the controlled and seminaturalistic experiment, respectively. The performance was higher in the healthy group where 96.85% of the tasks in the controlled experiment and 89.69% in the seminaturalistic were detected correctly. Finally, the detection ratio remains close ( ±6%) to the average value, for different task durations further attesting to the algorithms robustness. PMID:25966489

  1. Radiological Assessment of the Sacrofemoral Angle: A Novel Method to Measure the Range of Hip Joint Flexion

    PubMed Central

    Wei, Xian-Zhao; Xu, Xi-Ming; Wang, Fei; Li, Ming; Wang, Zi-Min

    2015-01-01

    Background: A quantitative and accurate measurement of the range of hip joint flexion (RHF) is necessarily required in the evaluation of disordered or artificial hip joint function. This study aimed to assess a novel method to measure RHF more accurately and objectively. Methods: Lateral radiographs were taken of 31 supine men with hip joints extended or flexed. Relevant angles were measured directly from the radiographs. The change in the sacrofemoral angle (SFA) (the angle formed between the axis of the femur and the line tangent to the upper endplate of S1) from hip joint extension to hip joint flexion, was proposed as the RHF. The validity of this method was assessed via concomitant measurements of changes in the femur-horizontal angle (between the axis of the femur and the horizontal line) and the sacrum-horizontal angle (SHA) (between the line tangent to the upper endplate of S1 and the horizontal line), the difference of which should equal the change in the SFA. Results: The mean change in the SFA was 112.5 ± 7.4°, and was independent of participant age, height, weight, or body mass index. The mean changes in the femur-horizontal and SHAs were 123.0 ± 6.4° and 11.4 ± 3.0°, respectively. This confirmed that the change of SFA between hip joint extension and hip joint flexion was equal to the difference between the changes in the femur-horizontal and SHAs. Conclusions: Using the SFA, to evaluate RHF could prevent compromised measurements due to the movements of pelvis and lumbar spine during hip flexion, and is, therefore, a more accurate and objective method with reasonable reliability and validity. PMID:26315079

  2. Limited-angle multi-energy CT using joint clustering prior and sparsity regularization

    NASA Astrophysics Data System (ADS)

    Zhang, Huayu; Xing, Yuxiang

    2016-03-01

    In this article, we present an easy-to-implement Multi-energy CT scanning strategy and a corresponding reconstruction method, which facilitate spectral CT imaging by improving the data efficiency the number-of-energy- channel fold without introducing visible limited-angle artifacts caused by reducing projection views. Leveraging the structure coherence at different energies, we first pre-reconstruct a prior structure information image using projection data from all energy channels. Then, we perform a k-means clustering on the prior image to generate a sparse dictionary representation for the image, which severs as a structure information constraint. We com- bine this constraint with conventional compressed sensing method and proposed a new model which we referred as Joint Clustering Prior and Sparsity Regularization (CPSR). CPSR is a convex problem and we solve it by Alternating Direction Method of Multipliers (ADMM). We verify our CPSR reconstruction method with a numerical simulation experiment. A dental phantom with complicate structures of teeth and soft tissues is used. X-ray beams from three spectra of different peak energies (120kVp, 90kVp, 60kVp) irradiate the phantom to form tri-energy projections. Projection data covering only 75◦ from each energy spectrum are collected for reconstruction. Independent reconstruction for each energy will cause severe limited-angle artifacts even with the help of compressed sensing approaches. Our CPSR provides us with images free of the limited-angle artifact. All edge details are well preserved in our experimental study.

  3. Influence of Joint Angle on EMG-Torque Model During Constant-Posture, Torque-Varying Contractions.

    PubMed

    Liu, Pu; Liu, Lukai; Clancy, Edward A

    2015-11-01

    Relating the electromyogram (EMG) to joint torque is useful in various application areas, including prosthesis control, ergonomics and clinical biomechanics. Limited study has related EMG to torque across varied joint angles, particularly when subjects performed force-varying contractions or when optimized modeling methods were utilized. We related the biceps-triceps surface EMG of 22 subjects to elbow torque at six joint angles (spanning 60° to 135°) during constant-posture, torque-varying contractions. Three nonlinear EMG σ -torque models, advanced EMG amplitude (EMG σ ) estimation processors (i.e., whitened, multiple-channel) and the duration of data used to train models were investigated. When EMG-torque models were formed separately for each of the six distinct joint angles, a minimum "gold standard" error of 4.01±1.2% MVC(F90) resulted (i.e., error relative to maximum voluntary contraction at 90° flexion). This model structure, however, did not directly facilitate interpolation across angles. The best model which did so achieved a statistically equivalent error of 4.06±1.2% MVC(F90). Results demonstrated that advanced EMG σ processors lead to improved joint torque estimation as do longer model training durations. PMID:25706722

  4. Locking Plate in Proximal Tibial Fracture: A Correlation between the Coronal Alignment of Tibia and Joint Screw Angle

    PubMed Central

    Oh, Jong-Keon; Varte, Lalrinliana; Ko, Jae-Han; Oh, Chang-Wug; Jung, Duk-Young; An, Hyonggin; Cho, Jae-Woo

    2013-01-01

    Purpose The purpose of this study is to evaluate the relationship between the angle formed between the proximal most screw through the locking compression plate-proximal lateral tibia (LCP PLT) and the joint line, and to evaluate if this angle can be used intraoperatively as an assessment tool to determine normal alignment of the tibia in the coronal plane. Materials and Methods There are two parts to this study: in the first part, LCP PLT was applied to 30 cadaveric adult tibia. The angle between the joint line and the proximal most screw was measured and termed as the 'joint screw angle' (JSA). In the second part, 56 proximal tibial fractures treated with LCP PLT were retrospectively studied. Two angles were measured on the radiographs, the medial proximal tibial angle (MPTA) and the JSA. Their relationship was analyzed statistically. Results The average JSA was 1.16 degrees in the anatomical study. Statistical analysis of the clinical study showed that the normal MPTA had a direct correlation with an acceptable JSA. Conclusion We therefore conclude that the JSA can be used intraoperatively to assess the achievement of a normal coronal axis. PMID:23549821

  5. A dowel exercise tool to improve finger range of motion.

    PubMed

    Zavala, Paul

    2014-01-01

    A new clinical and home dowel exercise tool to reduce joint stiffness of the fingers is introduced, along with the fabrication and the exercises that are used with it. Patients may utilize it to improve their finger joint range of motion, and facilitate tendon glide by isolating the targeted stiff joints of the fingers. PMID:24044953

  6. Wearable Goniometer and Accelerometer Sensory Fusion for Knee Joint Angle Measurement in Daily Life.

    PubMed

    Tognetti, Alessandro; Lorussi, Federico; Carbonaro, Nicola; de Rossi, Danilo

    2015-01-01

    Human motion analysis is crucial for a wide range of applications and disciplines. The development and validation of low cost and unobtrusive sensing systems for ambulatory motion detection is still an open issue. Inertial measurement systems and e-textile sensors are emerging as potential technologies for daily life situations. We developed and conducted a preliminary evaluation of an innovative sensing concept that combines e-textiles and tri-axial accelerometers for ambulatory human motion analysis. Our sensory fusion method is based on a Kalman filter technique and combines the outputs of textile electrogoniometers and accelerometers without making any assumptions regarding the initial accelerometer position and orientation. We used our technique to measure the flexion-extension angle of the knee in different motion tasks (monopodalic flexions and walking at different velocities). The estimation technique was benchmarked against a commercial measurement system based on inertial measurement units and performed reliably for all of the various tasks (mean and standard deviation of the root mean square error of 1:96 and 0:96, respectively). In addition, the method showed a notable improvement in angular estimation compared to the estimation derived by the textile goniometer and accelerometer considered separately. In future work, we will extend this method to more complex and multi-degree of freedom joints. PMID:26569249

  7. Wearable Goniometer and Accelerometer Sensory Fusion for Knee Joint Angle Measurement in Daily Life

    PubMed Central

    Tognetti, Alessandro; Lorussi, Federico; Carbonaro, Nicola; de Rossi, Danilo

    2015-01-01

    Human motion analysis is crucial for a wide range of applications and disciplines. The development and validation of low cost and unobtrusive sensing systems for ambulatory motion detection is still an open issue. Inertial measurement systems and e-textile sensors are emerging as potential technologies for daily life situations. We developed and conducted a preliminary evaluation of an innovative sensing concept that combines e-textiles and tri-axial accelerometers for ambulatory human motion analysis. Our sensory fusion method is based on a Kalman filter technique and combines the outputs of textile electrogoniometers and accelerometers without making any assumptions regarding the initial accelerometer position and orientation. We used our technique to measure the flexion-extension angle of the knee in different motion tasks (monopodalic flexions and walking at different velocities). The estimation technique was benchmarked against a commercial measurement system based on inertial measurement units and performed reliably for all of the various tasks (mean and standard deviation of the root mean square error of 1.96 and 0.96∘, respectively). In addition, the method showed a notable improvement in angular estimation compared to the estimation derived by the textile goniometer and accelerometer considered separately. In future work, we will extend this method to more complex and multi-degree of freedom joints. PMID:26569249

  8. Morphometric assessment of the canine hip joint using the dorsal acetabular rim view and the centre-edge angle.

    PubMed

    Meomartino, L; Fatone, G; Potena, A; Brunetti, A

    2002-01-01

    The dorsal acetabular rim (DAR) view of the hip joint can be used to assess the weightbearing portion of the acetabulum and the acetabular coverage, providing an adjunct to the conventional ventrodorsal (VD) view in the radiographic evaluation of hip dysplasia in the dog. A quantitative index of acetabular coverage in the DAR view, the acetabular slope (AS) angle, was originally proposed in 1990. The aim of the present study was to make a prospective, comparative assessment of a new parameter, the centre-edge (CE) angle, with the AS angle, for the evaluation of the acetabular coverage of the femoral head in the DAR view. The reliability and repeatability of the two parameters was assessed using the r(I) value of intraclass correlation coefficient (ICC) in a prospective study of 208 hip joints in large and giant breed dogs. An estimation of the added value of using the DAR view, compared with that of the VD standard view alone, was also assessed. The CE angle showed a higher r(I) value compared with the AS angle; in 26 per cent of hips of FCI classes A, B and C, the DAR view provided additional diagnostic information compared with the VD view, with respect to lateralisation and/or initial changes to the dorsal rim. It is concluded that the CE angle is more reliable than the AS angle in the evaluation of acetabular coverage, and that the DAR view provides valuable data compared with the VD view alone in the early stages of canine hip dysplasia. PMID:11833819

  9. Mallet finger - aftercare

    MedlinePlus

    Baseball finger - aftercare; Drop finger - aftercare; Avulsion fracture - mallet finger - aftercare ... Mallet finger occurs when you cannot straighten your finger: when you try to straighten it, the tip of your ...

  10. Development and Applications of a Self-Contained, Non-Invasive EVA Joint Angle and Muscle Fatigue Sensor System

    NASA Technical Reports Server (NTRS)

    Ranniger, C. U.; Sorenson, E. A.; Akin, D. L.

    1995-01-01

    The University of Maryland Space Systems Laboratory, as a participant in NASA's INSTEP program, is developing a non-invasive, self-contained sensor system which can provide quantitative measurements of joint angles and muscle fatigue in the hand and forearm. The goal of this project is to develop a system with which hand/forearm motion and fatigue metrics can be determined in various terrestrial and zero-G work environments. A preliminary study of the prototype sensor systems and data reduction techniques for the fatigue measurement system are presented. The sensor systems evaluated include fiberoptics, used to measure joint angle, surface electrodes, which measure the electrical signals created in muscle as it contracts; microphones, which measure the noise made by contracting muscle; and accelerometers, which measure the lateral muscle acceleration during contraction. The prototype sensor systems were used to monitor joint motion of the metacarpophalangeal joint and muscle fatigue in flexor digitorum superficialis and flexor carpi ulnaris in subjects performing gripping tasks. Subjects were asked to sustain a 60-second constant-contraction (isometric) exercise and subsequently to perform a repetitive handgripping task to failure. Comparison of the electrical and mechanical signals of the muscles during the different tasks will be used to evaluate the applicability of muscle signal measurement techniques developed for isometric contraction tasks to fatigue prediction in quasi-dynamic exercises. Potential data reduction schemes are presented.

  11. Accuracy of visual estimates of joint angle and angular velocity using criterion movements.

    PubMed

    Morrison, Craig S; Knudson, Duane; Clayburn, Colby; Haywood, Philip

    2005-06-01

    A descriptive study to document undergraduate physical education majors' (22.8 +/- 2.4 yr. old) estimates of sagittal plane elbow angle and angular velocity of elbow flexion visually was performed. 42 subjects rated videotape replays of 30 movements organized into three speeds of movement and two criterion elbow angles. Video images of the movements were analyzed with Peak Motus to measure actual values of elbow angles and peak angular velocity. Of the subjects 85.7% had speed ratings significantly correlated with true peak elbow angular velocity in all three angular velocity conditions. Few (16.7%) subjects' ratings of elbow angle correlated significantly with actual angles. Analysis of the subjects with good ratings showed the accuracy of visual ratings was significantly related to speed, with decreasing accuracy for slower speeds of movement. The use of criterion movements did not improve the small percentage of novice observers who could accurately estimate body angles during movement. PMID:16060418

  12. Effect of Hip Angle on Anterior Hip Joint Force during Gait

    PubMed Central

    Lewis, Cara L.; Sahrmann, Shirley A.; Moran, Daniel W.

    2010-01-01

    Anterior hip or groin pain is a common complaint for which people are referred for physical therapy. We have observed that people with anterior hip pain often walk in greater hip extension than people without anterior hip pain, and that the pain is reduced when they walk in less hip extension. Therefore, we investigated anterior hip joint forces which may contribute to anterior hip pain and examined the effect of end range hip extension on the anterior hip joint force during gait. To do this, we used a 6 degree of freedom, 3-dimensional musculoskeletal model to estimate hip joint forces during gait. Within subjects, the maximum anterior hip joint force for gait trials with the most hip extension was compared to the anterior hip joint force for gait trials with the least hip extension. The musculoskeletal model indicated that increasing the maximum end range hip extension when walking results in an increase in the anterior hip joint force when compared to walking in less hip extension. Walking in greater hip extension may result in an increase in the anterior hip joint force, and thereby contribute to anterior hip pain. The findings of this study provide some evidence supporting the use of gait modification to reduce anterior hip force when treating people with anterior hip pain. PMID:20934338

  13. Radiographic evaluation of perching-joint angles in cockatiels (Nymphicus hollandicus), Hispaniolan Amazon parrots (Amazona ventralis), and barred owls (Strix varia).

    PubMed

    Bonin, Glen; Lauer, Susanne K; Guzman, David Sanchez-Migallon; Nevarez, Javier; Tully, Thomas N; Hosgood, Giselle; Gaschen, Lorrie

    2009-06-01

    Information on perching-joint angles in birds is limited. Joint immobilization in a physiologic perching angle has the potential to result more often in complete restoration of limb function. We evaluated perching-joint angles in 10 healthy cockatiels (Nymphicus hollandicus), 10 Hispaniolan Amazons (Amazona ventralis), and 9 barred owls (Strix varia) and determined intra- and interobserver variability for goniometric measurements in 2 different radiographic projections. Intra- and interobserver variation was less than 7% for all stifle and intertarsal joint measurements but frequently exceeded 10% for the hip-joint measurements. Hip, stifle, and intertarsal perching angles differed significantly among cockatiels, Hispaniolan Amazon parrots, and barred owls. The accuracy of measurements performed on straight lateral radiographic projections with superimposed limbs was not consistently superior to measurements on oblique projections with a slightly rotated pelvis. Stifle and intertarsal joint angles can be measured on radiographs by different observers with acceptable variability, but intra- and interobserver variability for hip-joint-angle measurements is higher. PMID:19673455

  14. Finger Stiffness.

    PubMed

    Oosterhoff, Thijs C H; Nota, Sjoerd P F T; Ring, David

    2015-06-01

    Background Finger stiffness varies substantially in patients with hand and upper extremity illness and can be notably more than expected for a given pathophysiology. In prior studies, pain intensity and magnitude of disability consistently correlate with coping strategies such as catastrophic thinking and kinesiophobia, which can be characterized as overprotectiveness. In this retrospective study we address the primary research question whether patients with finger stiffness are more often overprotective when the primary pathology is outside the hand (e.g. distal radius fracture) than when it is located within the hand. Methods In an orthopaedic hand surgery department 160 patients diagnosed with more finger stiffness than expected for a given pathophysiology or time point of recovery between December 2006 and September 2012 were analyzed to compare the proportion of patients characterized as overprotective for differences by site of pathology: (1) inside the hand, (2) outside the hand, and (3) psychiatric etiology (e.g. clenched fist). Results Among 160 subjects with more finger stiffness than expected, 132 (82 %) were characterized as overprotective including 88 of 108 (81 %) with pathology in the hand, 39 of 44 (89 %) with pathology outside the hand, and 5 of 8 (63 %) with psychiatric etiology. These differences were not significant. Conclusions Overprotectiveness is common in patients with more finger stiffness than expected regardless the site and type of primary pathology. It seems worthwhile to recognize and treat maladaptive coping strategies early during recovery to limit impairment, symptoms, and disability. PMID:26078497

  15. Improvements of Travel-time Tomography Models from Joint Inversion of Multi-channel and Wide-angle Seismic Data

    NASA Astrophysics Data System (ADS)

    Begović, Slaven; Ranero, César; Sallarès, Valentí; Meléndez, Adrià; Grevemeyer, Ingo

    2016-04-01

    Commonly multichannel seismic reflection (MCS) and wide-angle seismic (WAS) data are modeled and interpreted with different approaches. Conventional travel-time tomography models using solely WAS data lack the resolution to define the model properties and, particularly, the geometry of geologic boundaries (reflectors) with the required accuracy, specially in the shallow complex upper geological layers. We plan to mitigate this issue by combining these two different data sets, specifically taking advantage of the high redundancy of multichannel seismic (MCS) data, integrated with wide-angle seismic (WAS) data into a common inversion scheme to obtain higher-resolution velocity models (Vp), decrease Vp uncertainty and improve the geometry of reflectors. To do so, we have adapted the tomo2d and tomo3d joint refraction and reflection travel time tomography codes (Korenaga et al, 2000; Meléndez et al, 2015) to deal with streamer data and MCS acquisition geometries. The scheme results in a joint travel-time tomographic inversion based on integrated travel-time information from refracted and reflected phases from WAS data and reflected identified in the MCS common depth point (CDP) or shot gathers. To illustrate the advantages of a common inversion approach we have compared the modeling results for synthetic data sets using two different travel-time inversion strategies: We have produced seismic velocity models and reflector geometries following typical refraction and reflection travel-time tomographic strategy modeling just WAS data with a typical acquisition geometry (one OBS each 10 km). Second, we performed joint inversion of two types of seismic data sets, integrating two coincident data sets consisting of MCS data collected with a 8 km-long streamer and the WAS data into a common inversion scheme. Our synthetic results of the joint inversion indicate a 5-10 times smaller ray travel-time misfit in the deeper parts of the model, compared to models obtained using just

  16. Muscle Activation Differs between Three Different Knee Joint-Angle Positions during a Maximal Isometric Back Squat Exercise

    PubMed Central

    Jarbas da Silva, Josinaldo; Jon Schoenfeld, Brad; Nardi, Priscyla Silva Monteiro; Pecoraro, Silvio Luis; D'Andréa Greve, Julia Maria; Hartigan, Erin

    2016-01-01

    The purpose of this study was to compare muscle activation of the lower limb muscles when performing a maximal isometric back squat exercise over three different positions. Fifteen young, healthy, resistance-trained men performed an isometric back squat at three knee joint angles (20°, 90°, and 140°) in a randomized, counterbalanced fashion. Surface electromyography was used to measure muscle activation of the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), semitendinosus (ST), and gluteus maximus (GM). In general, muscle activity was the highest at 90° for the three quadriceps muscles, yet differences in muscle activation between knee angles were muscle specific. Activity of the GM was significantly greater at 20° and 90° compared to 140°. The BF and ST displayed similar activation at all joint angles. In conclusion, knee position alters muscles activation of the quadriceps and gluteus maximus muscles. An isometric back squat at 90° generates the highest overall muscle activation, yet an isometric back squat at 140° generates the lowest overall muscle activation of the VL and GM only. PMID:27504484

  17. Joint angle and Doppler frequency estimation of coherent targets in monostatic MIMO radar

    NASA Astrophysics Data System (ADS)

    Cao, Renzheng; Zhang, Xiaofei

    2015-05-01

    This paper discusses the problem of joint direction of arrival (DOA) and Doppler frequency estimation of coherent targets in a monostatic multiple-input multiple-output radar. In the proposed algorithm, we perform a reduced dimension (RD) transformation on the received signal first and then use forward spatial smoothing (FSS) technique to decorrelate the coherence and obtain joint estimation of DOA and Doppler frequency by exploiting the estimation of signal parameters via rotational invariance techniques (ESPRIT) algorithm. The joint estimated parameters of the proposed RD-FSS-ESPRIT are automatically paired. Compared with the conventional FSS-ESPRIT algorithm, our RD-FSS-ESPRIT algorithm has much lower complexity and better estimation performance of both DOA and frequency. The variance of the estimation error and the Cramer-Rao Bound of the DOA and frequency estimation are derived. Simulation results show the effectiveness and improvement of our algorithm.

  18. Finger Multiplication

    ERIC Educational Resources Information Center

    Holmes, Bill

    2010-01-01

    The author has been prompted to write this article about finger multiplication for a number of reasons. Firstly there are a number of related articles in past issues of "Mathematics Teaching" ("MT") which have connections to this algorithm. Secondly, very few of his primary teaching students and professional colleagues appear to be aware of the…

  19. Joints at high angles to normal fault strike: an explanation using 3-D numerical models of fault-perturbed stress fields

    NASA Astrophysics Data System (ADS)

    Kattenhorn, Simon A.; Aydin, Atilla; Pollard, David D.

    2000-01-01

    Structural methods based on homogeneous stress states predict that joints growing in an extending crust form with strike orientations identical to normal faults. However, we document a field example where the strikes of genetically related normal faults and joints are almost mutually perpendicular. Field relationships allowed us to constrain the fracture sequence and tectonic environment for fault and joint growth. We hypothesize that fault slip can perturb the surrounding stress field in a manner that controls the orientations of induced secondary structures. Numerical models were used to examine the stress field around normal faults, taking into consideration the effects of 3-D fault shape, geometrical arrangement of overlapping faults, and a range of stress states. The calculated perturbed stress fields around model normal faults indicate that it is possible for joints to form at high angles to fault strike. Such joint growth may occur at the lateral tips of an isolated fault, but is most likely in a relay zone between overlapping faults. However, the angle between joints and faults is also influenced by the remote stress state, and is particularly sensitive to the ratio of fault-parallel to fault-perpendicular stress. As this ratio increases, joints can propagate away from faults at increasingly higher angles to fault strike. We conclude that the combined remote stress state and perturbed local stress field associated with overlapping fault geometries resulted in joint growth at high angles to normal fault strike at a field location in Arches National Park, Utah.

  20. Joint and angle-covariant spin measurements with a quadrupole magnetic field

    NASA Technical Reports Server (NTRS)

    Martens, Hans; Demuynck, Willem M.

    1994-01-01

    We study a Stern-Gerlach type setup, with a quadrupole magnetic field, for neutral particles of arbitrary spin. The Hamiltonian is of a form proposed for joint measurements of the incompatible observables. The measurement results are discussed, showing the limitation of such Hamiltonians. Some remarks are made on the relevance of covariance as a criterion for measurement schemes.

  1. Provocative mechanical tests of the peripheral nervous system affect the joint torque-angle during passive knee motion.

    PubMed

    Andrade, R J; Freitas, S R; Vaz, J R; Bruno, P M; Pezarat-Correia, P

    2015-06-01

    This study aimed to determine the influence of the head, upper trunk, and foot position on the passive knee extension (PKE) torque-angle response. PKE tests were performed in 10 healthy subjects using an isokinetic dynamometer at 2°/s. Subjects lay in the supine position with their hips flexed to 90°. The knee angle, passive torque, surface electromyography (EMG) of the semitendinosus and quadriceps vastus medialis, and stretch discomfort were recorded in six body positions during PKE. The different maximal active positions of the cervical spine (neutral; flexion; extension), thoracic spine (neutral; flexion), and ankle (neutral; dorsiflexion) were passively combined for the tests. Visual analog scale scores and EMG were unaffected by body segment positioning. An effect of the ankle joint was verified on the peak torque and knee maximum angle when the ankle was in the dorsiflexion position (P < 0.05). Upper trunk positioning had an effect on the knee submaximal torque (P < 0.05), observed as an increase in the knee passive submaximal torque when the cervical and thoracic spines were flexed (P < 0.05). In conclusion, other apparently mechanical unrelated body segments influence torque-angle response since different positions of head, upper trunk, and foot induce dissimilar knee mechanical responses during passive extension. PMID:24941915

  2. Robust Pilot Decontamination Based on Joint Angle and Power Domain Discrimination

    NASA Astrophysics Data System (ADS)

    Yin, Haifan; Cottatellucci, Laura; Gesbert, David; Muller, Ralf R.; He, Gaoning

    2016-06-01

    We address the problem of noise and interference corrupted channel estimation in massive MIMO systems. Interference, which originates from pilot reuse (or contamination), can in principle be discriminated on the basis of the distributions of path angles and amplitudes. In this paper we propose novel robust channel estimation algorithms exploiting path diversity in both angle and power domains, relying on a suitable combination of the spatial filtering and amplitude based projection. The proposed approaches are able to cope with a wide range of system and topology scenarios, including those where, unlike in previous works, interference channel may overlap with desired channels in terms of multipath angles of arrival or exceed them in terms of received power. In particular we establish analytically the conditions under which the proposed channel estimator is fully decontaminated. Simulation results confirm the overall system gains when using the new methods.

  3. Effects of pelvic adjustment on pelvic posture and angles of the lower limb joints during walking in female university students

    PubMed Central

    Cho, Misuk

    2016-01-01

    [Purpose] This study investigated the effects of pelvic adjustment on pelvic posture and lower limb joint angles during walking in female university students. [Subjects] Thirty healthy female university students were randomly assigned to an experimental group (pelvic adjustment group, n = 15) and a control group (stretching group, n = 15). [Methods] Pelvic adjustment was performed three times on the experimental group. The control group performed three sets of pelvic muscle stretching for 15 minutes. A back mapper and motion analysis equipment were used to measure pelvic posture and angles of lower limb joints for the experimental and control group. [Results] The values obtained before and after the intervention were compared. For the experimental group, the results were significantly different in terms of reduced differences in hip flexion between the left and right hips and in knee abduction between the left and right knees. Differences in pelvic position and pelvic torsion were also found in the experimental group. No significant differences in the control group were identified. [Conclusion] Pelvic adjustment affects pelvic position and torsion and this enhancement to pelvic stability decreases hip flexion and knee abduction during walking. PMID:27190468

  4. The relationship between unilateral mandibular angle fracture and temporomandibular joint function.

    PubMed

    Baltrusaityte, Ausra; Surna, Algimantas; Pileicikiene, Gaivile; Kubilius, Ricardas; Gleiznys, Alvydas; Zilinskas, Juozas

    2014-01-01

    PURPOSE. Aim of this study was to analyze relation of occlusal correction and alterations of temporomandibular joint function during treatment of unilateral mandibular fractures. MATERIALS AND METHODS. We compared 49 patients treated for unilateral mandibular fracture without occlusal correction with 21 patient treated for unilateral mandibular fracture along with early and consequent occlusal analysis and correction and with 49 control subjects. Patients' complaints, mandibular movements and occlusal parameters were evaluated during the period of healing. ZEBRIS ultrasound system (Jaw Motion Analyzer, Zebris Medical GmbH, Isny, Germany) was used for analysis of mandibular movements and T-Scan analyzer (Tekscan, Inc., Boston, MA, USA) was used for occlusal analysis. RESULTS. Findings of our study showed statistically significant (p<0.05) diminution of patients complaints, mandibular movement alterations and occlusal disturbances in patients who received occlusal correction during MF treatment if compared to patients treated without occlusal correction, except noises from the joint in the injured side and mandibular lateral track to the injured side in the final stage of investigation. Despite applied treatment recovery of the TMJ function was not complete and the investigated parameters remained worse if compared to the control group. CONCLUSIONS. Results of this study confirmed positive influence of early and subsequent occlusal analysis and correction during stages of MF treatment on diminution of functional alterations of the temporomandibular joint function. Timely occlusal correction improves and hastens process of rehabilitation therefore it is indispensable part of MF treatment. PMID:25471992

  5. Joint Replacement (Finger and Wrist Joints)

    MedlinePlus

    ... Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening Safety Turkey Carving Removing a Ring Español Artritis ... Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening Safety Turkey Carving Removing a Ring Español Artritis ...

  6. Comparison of Multi-angle Imaging SpectroRadiometer (MISR) joint aerosol product with high-resolution model output

    NASA Astrophysics Data System (ADS)

    Kalashnikova, O.; Lee, H.; Suzuki, K.; Braverman, A. J.

    2014-12-01

    The Multi-angle Imaging SpectroRadiometer (MISR) Level 3 Joint Aerosol product (JOINT_AS) provides global, descriptive summary of MISR Level 2 aerosol optical thickness (AOT) for eight different types of aerosols at 5 x 5 degrees of horizontal resolution in each month between March 2000 and present. Using Version 22 JOINT_AS, this study analyzed characteristics of the observed AOT distributions and compared various statistical moments of aerosol optical thickness derived from JOINT_AS with the results from Nonhydrostatic Icosahedral Atmospheric Model (NICAM) simulation. Overall, marginal distributions of AOT show highly positive skewness at many grid points. Some of the large skewness values are related to the problems in MISR's retrieval algorithm. For example, the positive skewness in AOT for strongly absorbing aerosols at mid- and high latitudes in winter results from few outlier values is due to cloud contamination over a wide area. Combined AOT for multiple MISR aerosol types is comparable to the AOT for carbonaceous, sulfate aerosols and dust particles from the NICAM simulation implemented with aerosol transport processes. NICAM's carbonaceous aerosols in the Southwest Africa show good agreement with MISR's strongly absorbing aerosols. The AOT of dust particles in MISR and NICAM exhibit similar spatial patterns over the Sahara desert. The AOT of nonabsorbing aerosols in MISR well represents spatial distributions of the sulfate aerosols originating from industrial complex over the Shandong Peninsula in China. Our results indicate that MISR's AOT for each aerosol type may be useful for monitoring biomass burning, dust storms and air pollution and evaluating chemistry climate models.

  7. Torque Control of Underactuated Tendon-driven Robotic Fingers

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E. (Inventor); Ihrke, Chris A. (Inventor); Reiland, Matthew J. (Inventor); Wampler, Charles W. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Bridgwater, Lyndon (Inventor)

    2013-01-01

    A robotic system includes a robot having a total number of degrees of freedom (DOF) equal to at least n, an underactuated tendon-driven finger driven by n tendons and n DOF, the finger having at least two joints, being characterized by an asymmetrical joint radius in one embodiment. A controller is in communication with the robot, and controls actuation of the tendon-driven finger using force control. Operating the finger with force control on the tendons, rather than position control, eliminates the unconstrained slack-space that would have otherwise existed. The controller may utilize the asymmetrical joint radii to independently command joint torques. A method of controlling the finger includes commanding either independent or parameterized joint torques to the controller to actuate the fingers via force control on the tendons.

  8. Comparison of joint angles and electromyographic activity of the lower extremities during standing with wearing standard and revised high-heeled shoes: A pilot study.

    PubMed

    Bae, Young-Hyeon; Ko, Mansoo; Lee, Suk Min

    2016-04-29

    Revised high-heeled shoes (HHSs) were designed to improve the shortcomings of standard HHSs. This study was conducted to compare revised and standard HHSs with regard to joint angles and electromyographic (EMG) activity of the lower extremities during standing. The participants were five healthy young women. Data regarding joint angles and EMG activity of the lower extremities were obtained under three conditions: barefoot, when wearing revised HHSs, and when wearing standard HHSs. Lower extremity joint angles in the three dimensional plane were confirmed using a VICON motion capture system. EMG activity of the lower extremities was measured using active bipolar surface EMG. Kruskal-Wallis one-way analysis of variance by rank applied to analyze differences during three standing conditions. Compared with the barefoot condition, the standard HHSs condition was more different than the revised HHSs condition with regard to lower extremity joint angles during standing. EMG activity of the lower extremities was different for the revised HHSs condition, but the differences among the three conditions were not significant. Wearing revised HHSs may positively impact joint angles and EMG activity of the lower extremities by improving body alignment while standing. PMID:27163313

  9. A structural design methodology for large angle articulated trusses considering realistic joint modeling

    NASA Astrophysics Data System (ADS)

    Thorwald, Gregory; Mikulas, Martin M., Jr.

    1994-01-01

    A structural design methodology is developed by quantifying the magnitude that large angle articulations and realistic modeling considerations adversely affect a truss's structural stiffness. Batten actuators provide the ability for the truss both to deploy and articulate. Such an articulated truss can be used in space crane applications. With geometry and modeling considerations identified and examined, strategies to alleviate the truss's stiffness reduction are developed and evaluated. Using these strategies, an improved articulated truss is then demonstrated. Observing that the design strategies are effective for the planar truss models similar 3-D truss models are then analyzed. The results show that the improvement strategies benefit both the 2-D and 3-D truss models.

  10. Behaviour of the electrical impedance myography in isometric contraction of biceps brachii at different elbow joint angles

    NASA Astrophysics Data System (ADS)

    Coutinho, A. B. B.; Jotta, B.; Pino, A. V.; Souza, M. N.

    2012-12-01

    Electrical impedance myography (EIM) can be understood as an experimental technique applied to evaluate bioelectrical impedance associated to the muscular activity. With the development of technique, some studies are trying to associate the EIM parameters with the morphological and physiological changes that occur in the muscle during contraction. In this context this work sought to associate EIM parameters observed during isometric contractions of the biceps brachii muscle at different elbow joint angles with the correspondent muscular force. Differently from previous works that did not observe significant correlation between those data, our findings point to high correlations between the some EIM resistive parameters and the muscle force. Despite the need of further investigation, our results indicated that EIM technique can be used to estimate muscle force in a noninvasive way.

  11. A Unitary ESPRIT Scheme of Joint Angle Estimation for MOTS MIMO Radar

    PubMed Central

    Wen, Chao; Shi, Guangming

    2014-01-01

    The transmit array of multi-overlapped-transmit-subarray configured bistatic multiple-input multiple-output (MOTS MIMO) radar is partitioned into a number of overlapped subarrays, which is different from the traditional bistatic MIMO radar. In this paper, a new unitary ESPRIT scheme for joint estimation of the direction of departure (DOD) and the direction of arrival (DOA) for MOTS MIMO radar is proposed. In our method, each overlapped-transmit-subarray (OTS) with the identical effective aperture is regarded as a transmit element and the characteristics that the phase delays between the two OTSs is utilized. First, the measurements corresponding to all the OTSs are partitioned into two groups which have a rotational invariance relationship with each other. Then, the properties of centro-Hermitian matrices and real-valued rotational invariance factors are exploited to double the measurement samples and reduce computational complexity. Finally, the close-formed solution of automatically paired DOAs and DODs of targets is derived in a new manner. The proposed scheme provides increased estimation accuracy with the combination of inherent advantages of MOTS MIMO radar with unitary ESPRIT. Simulation results are presented to demonstrate the effectiveness and advantage of the proposed scheme. PMID:25106023

  12. A unitary ESPRIT scheme of joint angle estimation for MOTS MIMO radar.

    PubMed

    Wen, Chao; Shi, Guangming

    2014-01-01

    The transmit array of multi-overlapped-transmit-subarray configured bistatic multiple-input multiple-output (MOTS MIMO) radar is partitioned into a number of overlapped subarrays, which is different from the traditional bistatic MIMO radar. In this paper, a new unitary ESPRIT scheme for joint estimation of the direction of departure (DOD) and the direction of arrival (DOA) for MOTS MIMO radar is proposed. In our method, each overlapped-transmit-subarray (OTS) with the identical effective aperture is regarded as a transmit element and the characteristics that the phase delays between the two OTSs is utilized. First, the measurements corresponding to all the OTSs are partitioned into two groups which have a rotational invariance relationship with each other. Then, the properties of centro-Hermitian matrices and real-valued rotational invariance factors are exploited to double the measurement samples and reduce computational complexity. Finally, the close-formed solution of automatically paired DOAs and DODs of targets is derived in a new manner. The proposed scheme provides increased estimation accuracy with the combination of inherent advantages of MOTS MIMO radar with unitary ESPRIT. Simulation results are presented to demonstrate the effectiveness and advantage of the proposed scheme. PMID:25106023

  13. Estimations of relative effort during sit-to-stand increase when accounting for variations in maximum voluntary torque with joint angle and angular velocity.

    PubMed

    Bieryla, Kathleen A; Anderson, Dennis E; Madigan, Michael L

    2009-02-01

    The main purpose of this study was to compare three methods of determining relative effort during sit-to-stand (STS). Fourteen young (mean 19.6+/-SD 1.2 years old) and 17 older (61.7+/-5.5 years old) adults completed six STS trials at three speeds: slow, normal, and fast. Sagittal plane joint torques at the hip, knee, and ankle were calculated through inverse dynamics. Isometric and isokinetic maximum voluntary contractions (MVC) for the hip, knee, and ankle were collected and used for model parameters to predict the participant-specific maximum voluntary joint torque. Three different measures of relative effort were determined by normalizing STS joint torques to three different estimates of maximum voluntary torque. Relative effort at the hip, knee, and ankle were higher when accounting for variations in maximum voluntary torque with joint angle and angular velocity (hip=26.3+/-13.5%, knee=78.4+/-32.2%, ankle=27.9+/-14.1%) compared to methods which do not account for these variations (hip=23.5+/-11.7%, knee=51.7+/-15.0%, ankle=20.7+/-10.4%). At higher velocities, the difference in calculating relative effort with respect to isometric MVC or incorporating joint angle and angular velocity became more evident. Estimates of relative effort that account for the variations in maximum voluntary torque with joint angle and angular velocity may provide higher levels of accuracy compared to methods based on measurements of maximal isometric torques. PMID:17720539

  14. Finger Injuries and Disorders

    MedlinePlus

    You use your fingers and thumbs to do everything from grasping objects to playing musical instruments to typing. When there is something wrong ... the skin of your palm. It causes the fingers to stiffen and bend. Trigger finger - an irritation ...

  15. Integration of marker and force data to compute three-dimensional joint moments of the thumb and index finger digits during pinch

    PubMed Central

    Nataraj, Raviraj; Li, Zong-Ming

    2014-01-01

    This study presents methodology to determine joint moments of the digits of the hand during pinch function. This methodology incorporates steps to identify marker-based kinematic data defining aligned coordinate systems for individual digit segments and joint center locations. The kinematic data are then transformed to a common reference frame along with the force data collected at pinch contact of a customized apparatus in three-dimensions (3-D). These methods were demonstrated with a pilot investigation to examine the static joint moments occurring during two-digit oppositional precision pinch at a particular endpoint force level applied at the digit pads. Notable abduction joint moments at the proximal joints of both digits were observed, which implicate the role of respective intrinsic and extrinsic muscles in maintaining pinch grasp. Examining differences in joint moment results when substituting select steps of this methodological approach suggested greater relative importance for joint center identification and segment coordinate system alignment. PMID:23947659

  16. High cycles fatigue damage of CFRP plates clamped by bolts for axial coupling joint with off-set angle during rotation

    NASA Astrophysics Data System (ADS)

    Ooka, Kazuaki; Okubo, Kazuya; Fujii, Toru; Umeda, Shinichi; Fujii, Masayuki; Sugiyama, Tetsuya

    2014-03-01

    This study discussed the change of residual fracture torque and the fatigue damage process of thin CFRP plates clamped by bolts for axial coupling joint, in which flexible deformation was allowed in the direction of off-set angle by the deflection of the CFRP plates while effective stiffness was obtained in rotational direction. Mechanically laminated 4 layers of the CFRP plates were repeatedly deflected during the rotation of axial coupling, when two axes were jointed with 3 degree of off-set angle, in which number of revolution was 1,800 rpm (30Hz of loading frequency). At first, the fracture morphology of specimen and the residual fracture torque was investigated after 1.0×107 cycles of repeated revolutions. The reduction ratio of spring constant was also determined by simple bending test after the fatigue. The residual fracture torque of the joint was determined on the rotational test machine after 1.0×107 cycles of fatigue. After rotations of cyclic fatigue, fiber breaking and wear of matrix were observed around the fixed parts compressed by washers for setting bolts. The reduction of spring constant of the CFRP plates was caused by the initiation of cyclic fatigue damages around the fixed parts, when the axial coupling joint was rotated with off-set angle. It was found that residual fracture torque of the joint was related with the specific fatigue damage of the CFRP observed in this study.

  17. Design and preliminary evaluation of the FINGER rehabilitation robot: controlling challenge and quantifying finger individuation during musical computer game play

    PubMed Central

    2014-01-01

    Background This paper describes the design and preliminary testing of FINGER (Finger Individuating Grasp Exercise Robot), a device for assisting in finger rehabilitation after neurologic injury. We developed FINGER to assist stroke patients in moving their fingers individually in a naturalistic curling motion while playing a game similar to Guitar Hero®a. The goal was to make FINGER capable of assisting with motions where precise timing is important. Methods FINGER consists of a pair of stacked single degree-of-freedom 8-bar mechanisms, one for the index and one for the middle finger. Each 8-bar mechanism was designed to control the angle and position of the proximal phalanx and the position of the middle phalanx. Target positions for the mechanism optimization were determined from trajectory data collected from 7 healthy subjects using color-based motion capture. The resulting robotic device was built to accommodate multiple finger sizes and finger-to-finger widths. For initial evaluation, we asked individuals with a stroke (n = 16) and without impairment (n = 4) to play a game similar to Guitar Hero® while connected to FINGER. Results Precision design, low friction bearings, and separate high speed linear actuators allowed FINGER to individually actuate the fingers with a high bandwidth of control (−3 dB at approximately 8 Hz). During the tests, we were able to modulate the subject’s success rate at the game by automatically adjusting the controller gains of FINGER. We also used FINGER to measure subjects’ effort and finger individuation while playing the game. Conclusions Test results demonstrate the ability of FINGER to motivate subjects with an engaging game environment that challenges individuated control of the fingers, automatically control assistance levels, and quantify finger individuation after stroke. PMID:24495432

  18. Compromised encoding of proprioceptively determined joint angles in older adults: the role of working memory and attentional load.

    PubMed

    Goble, Daniel J; Mousigian, Marianne A; Brown, Susan H

    2012-01-01

    Perceiving the positions and movements of one's body segments (i.e., proprioception) is critical for movement control. However, this ability declines with older age as has been demonstrated by joint angle matching paradigms in the absence of vision. The aim of the present study was to explore the extent to which reduced working memory and attentional load influence older adult proprioceptive matching performance. Older adults with relatively HIGH versus LOW working memory ability as determined by backward digit span and healthy younger adults, performed memory-based elbow position matching with and without attentional load (i.e., counting by 3 s) during target position encoding. Even without attentional load, older adults with LOW digit spans (i.e., 4 digits or less) had larger matching errors than younger adults. Further, LOW older adults made significantly greater errors when attentional loads were present during proprioceptive target encoding as compared to both younger and older adults with HIGH digit span scores (i.e., 5 digits or greater). These results extend previous position matching results that suggested greater errors in older adults were due to degraded input signals from peripheral mechanoreceptors. Specifically, the present work highlights the role cognitive factors play in the assessment of older adult proprioceptive acuity using memory-based matching paradigms. Older adults with LOW working memory appear prone to compromised proprioceptive encoding, especially when secondary cognitive tasks must be concurrently executed. This may ultimately result in poorer performance on various activities of daily living. PMID:22006273

  19. Noncontacting Finger Seal

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P. (Inventor); Steinetz, Bruce M. (Inventor)

    2004-01-01

    An annular finger seal is adapted to be interposed between a high pressure upstream region and a lower pressure downstream region to provide noncontact sealing along a rotatable member. The finger seal comprises axially juxtaposed downstream and upstream finger elements, each having integrally spaced fingers. The downstream fingers each have a lift pad, whereas the upstream fingers lack a pad. Each pad extends in a downstream direction. Each upstream finger is spaced from the rotating member a greater distance than each pad. Upon sufficient rotational speed of the rotating member, each pad is operative to lift and ride on a thin film of fluid intermediate the rotating member and the Pad.

  20. Articular synovial chondromatosis of the finger.

    PubMed

    Sano, Kazufumi; Hashimoto, Tomohisa; Kimura, Kazumasa; Ozeki, Satoru

    2014-10-01

    A 40-year-old woman presented with a six-month history of synovial chondromatosis of the metacarpophalangeal joint of the right ring finger, which was resected through both dorsal and volar incisions. To our knowledge there have been only 17 reported cases of articular synovial chondromatosis of the digital joint so far. We present a case affecting the metacarpophalangeal joint with a review of scattered information found in other 17 reports. PMID:23596991

  1. Comparisons of knee and ankle joint angles and ground reaction force according to functional differences during single-leg drop landing

    PubMed Central

    Kim, Kewwan; Jeon, Kyoungkyu

    2016-01-01

    [Purpose] The purpose of this study was to determine potential predictors of functional instability of the knee and ankle joints during single-leg drop landing based on the prior history of injury. [Subjects and Methods] The subjects were 24 collegiate soccer players without pain or dysfunction. To compare the differences between the stable and unstable sides during single-leg drop landing, 8 motion analysis cameras and a force plate were used. The Cortex 4 software was used for a biomechanical analysis of 3 events. An independent t-test was used for statistical comparison between both sides; p<0.05 indicated significance. [Results] The knee joint movements showed gradual flexion in the sagittal plane. The unstable-side ankle joint showed plantar flexion of approximately 2° relative to the stable side. In the coronal plane, the unstable-side knee joint differed from the stable side in its tendency for valgus movement. The unstable-side ankle joint showed contrasting movement compared with the stable side, and the difference was significant. Regarding the vertical ground reaction force, the stable side showed maximum knee flexion that was approximately 0.1 BW lower than that of the unstable side. [Conclusion] Increasing the flexion angle of the knee joint can help prevent injury during landing. PMID:27190444

  2. Tumour necrosis factor blockade for the treatment of erosive osteoarthritis of the interphalangeal finger joints: a double blind, randomised trial on structure modification

    PubMed Central

    Verbruggen, Gust; Wittoek, Ruth; Cruyssen, Bert Vander; Elewaut, Dirk

    2012-01-01

    Background Adalimumab blocks the action of tumor necrosis factor-α and reduces disease progression in rheumatoid arthritis and psoriatic arthritis. The effects of adalimumab in controlling progression of structural damage in erosive hand osteoarthritis (HOA) were assessed. Methods Sixty patients with erosive HOA on radiology received 40 mg adalimumab or placebo subcutaneously every two weeks during a 12-month randomized double-blind trial. Response was defined as the reduction in progression of structural damage according to the categorical anatomic phase scoring system. Furthermore, subchondral bone, bone plate erosion, and joint-space narrowing were scored according to the continuous Ghent University Score System (GUSSTM). Results The disease appeared to be active since 40.0% and 26,7% of patients out of the placebo and adalimumab group, respectively, showed at least one new interphalangeal (IP) joint that became erosive during the 12 months follow-up. These differences were not significant and the overall results showed no effect of adalimumab. Risk factors for progression were then identified and the presence of palpable soft tissue swelling at baseline was recognized as the strongest predictor for erosive progression. In this subpopulation at risk, statistically significant less erosive evolution on the radiological image (3.7%) was seen in the adalimumab treated group compared to the placebo group (14.5%) (P = 0.009). GUSSTM scoring confirmed a less rapid rate of mean increase in the erosion scores during the first 6 months of treatment in patients in adalimumab-treated patients. Conclusion Palpable soft tissue swelling in IP joints in patients with erosive HOA is a strong predictor for erosive progression. In these joints adalimumab significantly halted the progression of joint damage compared to placebo. PMID:22128078

  3. Hand and Finger Exercises

    MedlinePlus

    Hand and Finger Exercises  Place your palm flat on a table. Raise and lower your fingers one ... times for ____ seconds.  Pick up objects with your hand. Start out with larger objects. Repeat ____ times for ____ ...

  4. Speed invariance of independent control of finger movements in pianists

    PubMed Central

    Soechting, John F.

    2012-01-01

    Independent control of finger movements characterizes skilled motor behaviors such as tool use and musical performance. The purpose of the present study was to identify the effect of movement frequency (tempo) on individuated finger movements in piano playing. Joint motion at the digits was recorded while 5 expert pianists were playing 30 excerpts from musical pieces with different fingering and key locations either at a predetermined normal tempo or as fast as possible. Principal component analysis and cluster analysis using an expectation-maximization algorithm determined three distinct patterns of finger movement coordination for a keypress with each of the index, middle, ring, and little fingers at each of the two tempi. The finger kinematics of each coordination pattern was overall similar across the tempi. Tone sequences assigned into each cluster were also similar for both tempi. A linear regression analysis determined no apparent difference in the amount of movement covariation between the striking and nonstriking fingers at both metacarpo-phalangeal and proximal-interphalangeal joints across the two tempi, which indicated no effect of tempo on independent finger movements in piano playing. In addition, the standard deviation of interkeystroke interval across strokes did not differ between the two tempi, indicating maintenance of rhythmic accuracy of keystrokes. Strong temporal constraints on finger movements during piano playing may underlie the maintained independent control of fingers over a wider range of tempi, a feature being likely to be specific to skilled pianists. PMID:22815403

  5. Radiographic anatomy of the rabbit skull, with particular reference to the tympanic bulla and temporomandibular joint. Part 2: Ventral and dorsal rotational angles.

    PubMed

    King, A M; Cranfield, F; Hall, J; Hammond, G; Sullivan, M

    2010-11-01

    This is the second part of a two-part study to document rabbit skull radiographic anatomy with particular reference to the temporomandibular joint (TMJ) and tympanic bulla (TB), and identify views that allowed their optimal visualisation. Equipment was used that allowed repeatable positioning of skulls at known rotational angles in ventral (rostrocaudal to ventrodorsal) with the mouth closed and open, and dorsal (rostrocaudal to dorsoventral position) directions. The views were repeated with lead markers attached to anatomical features and cadaver heads. The TBs were visible between 40° and 90° from rostrocaudal in both directions, but opening the mouth did not improve visualisation. The TMJs were visible until 40° in a ventral direction, but only 20° in a dorsal one. Opening the mouth slightly altered the regions of the joint being skylined, but did not otherwise enhance imaging of this region. PMID:19717319

  6. Extrinsic and intrinsic index finger muscle attachments in an OpenSim upper-extremity model.

    PubMed

    Lee, Jong Hwa; Asakawa, Deanna S; Dennerlein, Jack T; Jindrich, Devin L

    2015-04-01

    Musculoskeletal models allow estimation of muscle function during complex tasks. We used objective methods to determine possible attachment locations for index finger muscles in an OpenSim upper-extremity model. Data-driven optimization algorithms, Simulated Annealing and Hook-Jeeves, estimated tendon locations crossing the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints by minimizing the difference between model-estimated and experimentally-measured moment arms. Sensitivity analysis revealed that multiple sets of muscle attachments with similar optimized moment arms are possible, requiring additional assumptions or data to select a single set of values. The most smooth muscle paths were assumed to be biologically reasonable. Estimated tendon attachments resulted in variance accounted for (VAF) between calculated moment arms and measured values of 78% for flex/extension and 81% for ab/adduction at the MCP joint. VAF averaged 67% at the PIP joint and 54% at the DIP joint. VAF values at PIP and DIP joints partially reflected the constant moment arms reported for muscles about these joints. However, all moment arm values found through optimization were non-linear and non-constant. Relationships between moment arms and joint angles were best described with quadratic equations for tendons at the PIP and DIP joints. PMID:25281408

  7. The effects of shoulder joint abduction angles on the muscle activity of the serratus anterior muscle and the upper trapezius muscle while vibrations are applied

    PubMed Central

    Jung, Da-eun; Moon, Dong-chul

    2015-01-01

    [Purpose] The purpose of this study was to examine the ratio between the upper trapezius and the serratus anterior muscles during diverse shoulder abduction exercises applied with vibrations in order to determine the appropriate exercise methods for recovery of scapular muscle balance. [Subjects and Methods] Twenty-four subjects voluntarily participated in this study. The subjects performed shoulder abduction at various shoulder joint abduction angles (90°, 120°, 150°, 180°) with oscillation movements. [Results] At 120°, all the subjects showed significant increases in the muscle activity of the serratus anterior muscle in comparison with the upper trapezius muscle. However, no significant difference was found at angles other than 120°. [Conclusion] To selectively strengthen the serratus anterior, applying vibration stimuli at the 120° shoulder abduction position is considered to be appropriate. PMID:25642052

  8. Radiographic anatomy of the rabbit skull with particular reference to the tympanic bulla and temporomandibular joint: Part 1: Lateral and long axis rotational angles.

    PubMed

    King, A M; Cranfield, F; Hall, J; Hammond, G; Sullivan, M

    2010-11-01

    Radiography is frequently used to investigate otitis media and dental disease in rabbits, although there are few detailed reports regarding the radiographic anatomy of the rabbit skull. The aim of this study was to document rabbit skull radiographic anatomy, with particular reference to the tympanic bulla (TB) and temporomandibular joint (TMJ), and to identify views that allowed optimal assessment of these areas. Equipment was used that allowed repeatable positioning of skulls at known rotational angles in lateral (lateral to rostrocaudal) and long axis (lateral to ventrodorsal) directions. The views were repeated with lead markers attached to anatomical features and cadaver heads. The TB could be best examined between 30° and 60° in both planes. The TMJ was best visualised between 70° and 90° in a lateral direction, particularly along a true rostrocaudal plane, but could not be imaged well at any of the long axis rotational angles. Similar images were obtained using cadavers. PMID:19853482

  9. Finger snapping during seizures.

    PubMed

    Overdijk, M J; Zijlmans, M; Gosselaar, P H; Olivier, A; Leijten, F S S; Dubeau, F

    2014-01-01

    We describe two patients who showed snapping of the right hand fingers during invasive intracranial EEG evaluation for epilepsy surgery. We correlated the EEG changes with the finger-snapping movements in both patients to determine the underlying pathophysiology of this phenomenon. At the time of finger snapping, EEG spread from the supplementary motor area towards the temporal region was seen, suggesting involvement of these sites. PMID:25667884

  10. Fingers that change color

    MedlinePlus

    ... conditions can cause fingers or toes to change color: Buerger disease Chilblains. Painful inflammation of small blood vessels. Cryoglobulinemia Frostbite Necrotizing vasculitis Peripheral artery disease ...

  11. 38 CFR 4.71 - Measurement of ankylosis and joint motion.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... pronation. Motion of the thumb and fingers should be described by appropriate reference to the joints (See... thumb can approximate the fingers, or how near the tips of the fingers can approximate the...

  12. 38 CFR 4.71 - Measurement of ankylosis and joint motion.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... pronation. Motion of the thumb and fingers should be described by appropriate reference to the joints (See... thumb can approximate the fingers, or how near the tips of the fingers can approximate the...

  13. 38 CFR 4.71 - Measurement of ankylosis and joint motion.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... pronation. Motion of the thumb and fingers should be described by appropriate reference to the joints (See... thumb can approximate the fingers, or how near the tips of the fingers can approximate the...

  14. 38 CFR 4.71 - Measurement of ankylosis and joint motion.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... pronation. Motion of the thumb and fingers should be described by appropriate reference to the joints (See... thumb can approximate the fingers, or how near the tips of the fingers can approximate the...

  15. 38 CFR 4.71 - Measurement of ankylosis and joint motion.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... pronation. Motion of the thumb and fingers should be described by appropriate reference to the joints (See... thumb can approximate the fingers, or how near the tips of the fingers can approximate the...

  16. Bilateral Volleyball-Related Deformity of the Little Fingers: Mallet Finger and Clinodactyly Mimic

    PubMed Central

    Uslu, Mustafa; Solak, Kazim; Ozsahin, Mustafa; Uzun, Hakan

    2011-01-01

    A 14-year-old male high school volleyball player was seen to evaluate right- and left-hand little-finger distal interphalangeal joint deformity and pain. His symptoms began during his second season of competitive play. The distal interphalangeal (DIP) joints of the little fingers flexed 20-30°, and a 10-15° valgus deformity was seen at the same joints. Pain was relieved with rest but returned immediately after playing volleyball, so plain radiographs were obtained. The flexion and valgus deformity was obvious on plain radiographs and through a clinical examination. Thus, a bilateral little-finger distal phalanx base epiphysis injury was seen. This injury is characterized by a biplanar Salter Harris physeal injury; type 5 on anteroposterior radiographs and type 2 on lateral plain radiographs. The deformity occurred as a result of competitive volleyball play. To our knowledge, this is the first reported case of a bilateral biplanar physial injury of the base of distal phalanges of the little fingers. Flexion and valgus deformities of DIP joints are a result of repeated micro traumas around the physis. Key points As a result of repeated micro traumas to the physial region, flexion and valgus deformities of the distal interphalangeal (DIP) joints should be occurred. Sports injuries to the hand often require treatment in orthopedic departments to avoid permanent deformities. Short- or long-term functional results can be gained by simple splinting procedures and abstention from play. PMID:24149318

  17. Effect of Resistance Training Maintaining the Joint Angle-torque Profile Using a Haptic-based Machine on Shoulder Internal and External Rotation

    PubMed Central

    Kim, Yeonghun; Lee, Kunwoo; Moon, Jeheon; Koo, Dohoon; Park, Jaewoo; Kim, Kyengnam; Hong, Daehie; Shin, Inshik

    2014-01-01

    [Purpose] The aim of this study was to present an individualized resistance training method to enable exercise while maintaining an exercise load that is set according to an individual’s joint angle-torque using a haptic-based resistance training machine. [Methods] Five participants (machine group) performed individualized shoulder internal and external rotation training with a haptic resistance training machine, while another five participants performed general dumbbell-based shoulder internal and external rotation training for eight weeks. Internal and external rotation powers of subjects were measured using an isokinetic machine before and after training. [Results] The average powers of both shoulder internal and external rotation has been improved after training (25.72%, 13.62%). The improvement in power of external rotation in the machine group was significantly higher than that in the control group. [Conclusion] This study proposes a haptic-based individualized rotator cuff muscle training method. The training protocol maintaining the joint angle-torque profile showed better improvement of shoulder internal/external rotation than dumbbell training. PMID:24764626

  18. Effect of core muscle thickness and static or dynamic balance on prone bridge exercise with sling by shoulder joint angle in healthy adults

    PubMed Central

    Park, Mi Hwa; Yu, Jae Ho; Hong, Ji Heon; Kim, Jin Seop; Jung, Sang Woo; Lee, Dong Yeop

    2016-01-01

    [Purpose] To date, core muscle activity detected using ultrasonography during prone bridge exercises has not been reported. Here we investigated the effects of core muscle thickness and balance on sling exercise efficacy by shoulder joint angle in healthy individuals. [Subjects and Methods] Forty-three healthy university students were enrolled in this study. Ultrasonography thickness of external oblique, internal oblique, and transversus abdominis during sling workouts was investigated. Muscle thickness was measured on ultrasonography imaging before and after the experiment. Dynamic balance was tested using a functional reaching test. Static balance was tested using a Tetrax Interactive Balance System. [Results] Different muscle thicknesses were observed during the prone bridge exercise with the shoulder flexed at 60°, 90° or 120°. Shoulder flexion at 60° and 90° in the prone bridge exercise with a sling generated the greatest thickness of most transversus abdominis muscles. Shoulder flexion at 120° in the prone bridge exercise with a sling generated the greatest thickness of most external oblique muscles. [Conclusion] The results suggest that the prone bridge exercise with shoulder joint angle is an effective method of increasing global and local muscle strength. PMID:27134390

  19. A reverse flow cross finger pedicle skin flap from hemidorsum of finger.

    PubMed

    Mishra, Satyanarayan; Manisundaram, S

    2010-04-01

    A reverse-flow cross-finger pedicle skin flap raised from the hemidorsum has been used, which is a modification of the distally based dorsal cross-finger flap. The flap is raised from the hemidorsum at a plane above the paratenon, the distal-most location of the base being at the level of the distal interphalangeal joint. Thirty-two flaps were used from as many fingers of as many patients. Of these, 31 (97%) flaps survived fully; there was stiffness of finger in one (3%) patient and the two-point discrimination was 4-8mm (n=14). Follow-up period was 2 months to 3 years, the median being 1 year and 3 months. The advantages of this flap are that there is less disruption of veins and less visible disfigurement of the dorsum of the finger when compared to other pedicled cross-finger skin flaps. The disadvantage of this flap is its restricted width. It is recommended as the cross-finger pedicle skin flap of choice when the defect is not wide. PMID:19386561

  20. Rolling friction robot fingers

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    1992-01-01

    A low friction, object guidance, and gripping finger device for a robotic end effector on a robotic arm is disclosed, having a pair of robotic fingers each having a finger shaft slideably located on a gripper housing attached to the end effector. Each of the robotic fingers has a roller housing attached to the finger shaft. The roller housing has a ball bearing mounted centering roller located at the center, and a pair of ball bearing mounted clamping rollers located on either side of the centering roller. The object has a recess to engage the centering roller and a number of seating ramps for engaging the clamping rollers. The centering roller acts to position and hold the object symmetrically about the centering roller with respect to the X axis and the clamping rollers act to position and hold the object with respect to the Y and Z axis.

  1. Prediction of contact forces of underactuated finger by adaptive neuro fuzzy approach

    NASA Astrophysics Data System (ADS)

    Petković, Dalibor; Shamshirband, Shahaboddin; Abbasi, Almas; Kiani, Kourosh; Al-Shammari, Eiman Tamah

    2015-12-01

    To obtain adaptive finger passive underactuation can be used. Underactuation principle can be used to adapt shapes of the fingers for grasping objects. The fingers with underactuation do not require control algorithm. In this study a kinetostatic model of the underactuated finger mechanism was analyzed. The underactuation is achieved by adding the compliance in every finger joint. Since the contact forces of the finger depend on contact position of the finger and object, it is suitable to make a prediction model for the contact forces in function of contact positions of the finger and grasping objects. In this study prediction of the contact forces was established by a soft computing approach. Adaptive neuro-fuzzy inference system (ANFIS) was applied as the soft computing method to perform the prediction of the finger contact forces.

  2. Neuro-sliding mode control with modular models for control of knee-joint angle using quadriceps electrical stimulation.

    PubMed

    Ajoudani, Arash; Erfanian, Abbas

    2007-01-01

    In this paper, we propose a control methodology which is based on synergistic combination of a single-neuron controller with sliding mode control (SMC) for control of knee-joint position in paraplegic subjects with quadriceps stimulation. The control law will be switched from the sliding mode control to neural control, when the state trajectory of system enters in some boundary layer around the sliding surface. The main drawback of the standard sliding modes is mostly related to the so-called chattering caused by the high-frequency control switching. The value of switching gain depends on the bounds of system uncertainties. The system with large uncertainties needs to use a higher switching gain. This will, however, result in the high-frequency control switching and chattering across the sliding surface. To avoid such a condition, it is necessary to decrease the system uncertainty. To decrease the uncertainty, an accurate model of the system is required. For this purpose, we present a modular approach to modeling the knee-joint dynamics. Extensive experiments on healthy and paraplegic subjects are provided to demonstrate the robustness, stability and tracking accuracy of the neuro-SMC. The experimental results show that the neuro-SMC provides excellent tracking control for different reference trajectories and could generate control signals to compensate the muscle fatigue. PMID:18002483

  3. Large displacement spherical joint

    DOEpatents

    Bieg, Lothar F.; Benavides, Gilbert L.

    2002-01-01

    A new class of spherical joints has a very large accessible full cone angle, a property which is beneficial for a wide range of applications. Despite the large cone angles, these joints move freely without singularities.

  4. Multiple Fingers - One Gestalt.

    PubMed

    Lezkan, Alexandra; Manuel, Steven G; Colgate, J Edward; Klatzky, Roberta L; Peshkin, Michael A; Drewing, Knut

    2016-01-01

    The Gestalt theory of perception offered principles by which distributed visual sensations are combined into a structured experience ("Gestalt"). We demonstrate conditions whereby haptic sensations at two fingertips are integrated in the perception of a single object. When virtual bumps were presented simultaneously to the right hand's thumb and index finger during lateral arm movements, participants reported perceiving a single bump. A discrimination task measured the bump's perceived location and perceptual reliability (assessed by differential thresholds) for four finger configurations, which varied in their adherence to the Gestalt principles of proximity (small versus large finger separation) and synchrony (virtual spring to link movements of the two fingers versus no spring). According to models of integration, reliability should increase with the degree to which multi-finger cues integrate into a unified percept. Differential thresholds were smaller in the virtual-spring condition (synchrony) than when fingers were unlinked. Additionally, in the condition with reduced synchrony, greater proximity led to lower differential thresholds. Thus, with greater adherence to Gestalt principles, thresholds approached values predicted for optimal integration. We conclude that the Gestalt principles of synchrony and proximity apply to haptic perception of surface properties and that these principles can interact to promote multi-finger integration. PMID:26863671

  5. Finger and toenail onycholysis.

    PubMed

    Zaias, N; Escovar, S X; Zaiac, M N

    2015-05-01

    Onycholysis - the separation of the nail plate from the nail bed occurs in fingers and toenails. It is diagnosed by the whitish appearance of the separated nail plate from the nail bed. In fingers, the majority is caused by trauma, manicuring, occupational or self-induced behavior. The most common disease producing fingernail onycholysis is psoriasis and pustular psoriasis. Phototoxic dermatitis, due to drugs can also produce finger onycholysis. Once the separation occurs, the environmental flora sets up temporary colonization in the available space. Finger onycholysis is most common in women. Candida albicans is often recovered from the onycholytic space. Many reports, want to associate the yeast as cause and effect, but the data are lacking and the treatment of the candida does not improve finger onycholysis. A reasonable explanation for the frequent isolation of Candida and Pseudomonas in fingernail onycholysis in women, is the close proximity the fingers have to the vaginal and gastrointestinal tract. Fifty per cent of humans harbour C. albicans in the GI tract and it is frequently carried to the vagina during hygienic practices. Finger onycholysis is best treated by drying the nail 'lytic' area with a hair blower, since all colonizing biota are moisture loving and perish in a dry environment. Toenail onycholysis has a very different etiology. It is mechanical, the result of pressure on the toes from the closed shoes, while walking, because of the ubiquitous uneven flat feet producing an asymmetric gait with more pressure on the foot with the flatter sole. PMID:25512134

  6. Changes in Femoral Posterior Condylar Offset, Tibial Posterior Slope Angle, and Joint Line Height after Cruciate-Retaining Total Knee Arthroplasty

    PubMed Central

    Song, Sang Jun; Kim, Kang Il; Jeong, Ho Yeon

    2016-01-01

    Purpose Changes in the femoral posterior condylar offset (PCO), tibial posterior slope angle (PSA), and joint line height (JLH) after cruciate-retaining total knee arthroplasty (CR-TKA) were evaluated to determine their influence on the flexion angle. Materials and Methods A total of 125 CR-TKAs performed on 110 patients were retrospectively reviewed. Pre- and postoperative PCO, PSA, and JLH were compared using correlation analysis. Independent factors affecting the postoperative flexion angle of the knee were analyzed. Results The PCO was 28.2±2.0 mm (range, 24.5 to 33.1 mm) preoperatively and 26.7±1.8 mm (range, 22.2 to 31.2 mm) postoperatively (r=0.807, p<0.001). The PSA was 10.4°±4.9° (range, 1.6° to 21.2°) preoperatively and decreased to 4.9°±2.0° (2.2° to 10.7°) postoperatively (r=–0.023, p=0.800). The JLH was 16.2±3.0 mm (range, 10.2 to 27.5 mm) preoperatively and 16.1±2.6 mm (range, 11.1 to 24.8 mm) postoperatively (r=0.505, p<0.001). None of the independent factors affected the flexion angle (p>0.291). Conclusions Although the PCO and JLH did not change significantly after CR-TKA, the PSA decreased by 5.5° with a small range of variation. Restoration of the PCO and JLH could promote optimization of knee flexion in spite of the decreased PSA after CR-TKA. PMID:26955610

  7. Social categorization and cooperation in motor joint action: evidence for a joint end-state comfort.

    PubMed

    Dötsch, Dominik; Schubö, Anna

    2015-08-01

    The present study investigated to what extent group membership affects an actor's representation of their partner's task in cooperative joint action. Participants performed a joint pick-and-place task in a naturalistic, breakfast-table-like paradigm which allowed the demonstration of varying degrees of cooperation. Participants transported a wooden cup from one end of a table to the other, with one actor moving it to an intermediate position from where their partner transported it to a goal position. Hand and finger movements were recorded via 3D motion tracking to assess actors' cooperative behavior. Before the joint action task was performed, participants were categorized as belonging to the same or to different groups, supposedly based on an assessment of their cognitive processing styles. Results showed that the orientation of the actors' fingers when picking up the cup was affected by its required angle at the goal position. When placing the cup at the intermediate position, most actors adapted the rotation of the cup's handle to the joint action goal, thereby facilitating the partner's subsequent movement. Male actors demonstrated such cooperative behavior only when performing the task together with an ingroup partner, while female actors demonstrated cooperative behavior irrespective of social categorization. These results suggest that actors tend to represent a partner's end-state comfort and integrate it into their own movement planning in cooperative joint action. However, social factors like group membership may modulate this tendency. PMID:25963752

  8. Fingering in Confined Elastic Layers

    NASA Astrophysics Data System (ADS)

    Biggins, John; Mahadevan, L.; Wei, Z.; Saintyves, Baudouin; Bouchaud, Elizabeth

    2015-03-01

    Fingering has recently been observed in soft highly elastic layers that are confined between and bonded to two rigid bodies. In one case an injected fluid invades the layer in finger-like protrusions at the layer's perimeter, a solid analogue of Saffman-Taylor viscous fingering. In a second case, separation of the rigid bodies (with maintained adhesion to the layer) leads air to the formation of similar fingers at the layer's perimeter. In both cases the finger formation is reversible: if the fluid is removed or the separation reduced, the fingers vanish. In this talk I will discuss a theoretical model for such elastic fingers that shows that the origin of the fingers is large-strain geometric non-linearity in the elasticity of soft solids. Our simplified elastic model unifies the two types of fingering and accurately estimates the thresholds and wavelengths of the fingers.

  9. The Manumeter: A non-obtrusive wearable device for monitoring spontaneous use of the wrist and fingers

    PubMed Central

    Rowe, Justin B.; Friedman, Nizan; Bachman, Mark; Reinkensmeyer, David J.

    2014-01-01

    This paper describes the design and pilot testing of a novel device for unobtrusive monitoring of wrist and hand movement through a sensorized watch and a magnetic ring system called the manumeter. The device senses the magnetic field of the ring through two triaxial magnetometers and records the data to onboard memory which can be analyzed later by connecting the watch unit to a computer. Wrist and finger joint angles are estimated using a radial basis function network. We compared joint angle estimates collected using the manumeter to direct measurements taken using a passive exoskeleton and found that after a 60 minute trial, 95% of the radial/ulnar deviation, wrist flexion/extension and finger flexion/extension estimates were within 2.4, 5.8, and 4.7 degrees of their actual values respectively. The device measured angular distance traveled for these three joints within 10.4%, 4.5%, and 14.3 % of their actual values. The manumeter has potential to improve monitoring of real world use of the hand after stroke and in other applications. PMID:24187216

  10. Tendon Driven Finger Actuation System

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Reich, David M. (Inventor); Bridgwater, Lyndon (Inventor); Linn, Douglas Martin (Inventor); Askew, Scott R. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Hargrave, Brian (Inventor); Valvo, Michael C. (Inventor); Abdallah, Muhammad E. (Inventor); Permenter, Frank Noble (Inventor); Mehling, Joshua S. (Inventor)

    2013-01-01

    A humanoid robot includes a robotic hand having at least one finger. An actuation system for the robotic finger includes an actuator assembly which is supported by the robot and is spaced apart from the finger. A tendon extends from the actuator assembly to the at least one finger and ends in a tendon terminator. The actuator assembly is operable to actuate the tendon to move the tendon terminator and, thus, the finger.

  11. Fjord geometry observed in viscous fingering*

    NASA Astrophysics Data System (ADS)

    Thrasher, Matt; Ristroph, Leif; Swinney, Harry L.; Mineev-Weinstein, Mark

    2004-11-01

    Injecting a less viscous fluid (air) into a more viscous fluid (oil) produces an unstable finger of air penetrating into the oil. For sufficiently large forcing, the tip of a finger splits. The region of oil left between adjacent fingers is called a fjord. We characterize the width, widening, and bending of fjords in experiments in a rectangular Hele-Shaw cell. The channel confines air and 50 cS silicone oil between two glass plates, which are 2500 mm long and 250 mm wide with a separation of 0.5 mm. The width of the base of a fjord is found to be approximately one-half of the capillary length scale. From this base, the fjords open with a distribution of angles having a mean of about 9 ^rc, which contradicts theoretical predictions of an opening angle of 0 ^rc (parallel sides). Finally, the centerline of a fjord bends. Lajeunesse and Couder [1] account for the bending of a fjord on a single, one-half width finger. We test the validity of their idea on the tip-splitting of more complicated interfaces and on the widening of fjords. *Supported by ONR [1] E. Lajeunesse and Y. Couder, J. Fluid. Mech. 419, 125 (2000).

  12. Osseointegrated finger prostheses.

    PubMed

    Doppen, P; Solomons, M; Kritzinger, S

    2009-02-01

    Amputation of a digit can lead to functional and psychological problems and patients can benefit from digital prostheses. Unfortunately, standard prostheses are often unstable, particularly when fitted over short amputation stumps. Prosthesis fixation by osseointegration is widely used in oral and extraoral applications and may help avoid the problem of instability. This paper reports the results of four patients with five finger amputations who were treated with osseointegrated implants to attach finger prostheses. One implant failed to osseointegrate and the procedure was abandoned. Three patients were successfully treated to completion of three finger prostheses and are extremely satisfied with their outcomes, both cosmetically and functionally, with osseoperception reported by all three patients. PMID:19091736

  13. Joint Effects of Intraocular Pressure and Myopia on Risk of Primary Open-Angle Glaucoma: The Singapore Epidemiology of Eye Diseases Study.

    PubMed

    Tham, Yih-Chung; Aung, Tin; Fan, Qiao; Saw, Seang-Mei; Siantar, Rosalynn Grace; Wong, Tien Y; Cheng, Ching-Yu

    2016-01-01

    We examined the joint effects of intraocular pressure (IOP) and myopia on the risk of primary open angle glaucoma (POAG) in a multi-ethnic Asian population. A total of 9,422 participants (18,469 eyes) in the Singapore Epidemiology of Eye Diseases Study were included. Of them, 213 subjects (273 eyes) had POAG. All participants underwent standardised examinations. The independent and joint effects of IOP and myopia on POAG were examined using logistic regression models. Generalised estimating equation models were used to account for correlation between eyes. Higher IOP, longer axial length, and more negative spherical equivalent were independently associated with POAG, after adjusting for relevant covariates (all P ≤ 0.005). Significant interaction between IOP and myopia on POAG was observed (P interaction = 0.025). Eyes with moderate-to-high myopia (<-3.0 dioptres) with high IOP (≥20 mmHg) were 4.27 times (95% CI, 2.10-8.69) likely to have POAG, compared to eyes without myopia (>-0.5 dioptres) and with IOP <20 mmHg. Eyes with AL of ≥25.5 mm and high IOP (≥20 mmHg) were 16.22 times (95% CI, 7.73 to 34.03) likely to have POAG, compared to eyes with shorter AL (<23.5 mm) and lower IOP (<20 mmHg). These findings may provide additional insights into the pathophysiology of POAG and are particularly relevant for Asian populations. PMID:26758554

  14. Joint Effects of Intraocular Pressure and Myopia on Risk of Primary Open-Angle Glaucoma: The Singapore Epidemiology of Eye Diseases Study

    PubMed Central

    Tham, Yih-Chung; Aung, Tin; Fan, Qiao; Saw, Seang-Mei; Siantar, Rosalynn Grace; Wong, Tien Y.; Cheng, Ching-Yu

    2016-01-01

    We examined the joint effects of intraocular pressure (IOP) and myopia on the risk of primary open angle glaucoma (POAG) in a multi-ethnic Asian population. A total of 9,422 participants (18,469 eyes) in the Singapore Epidemiology of Eye Diseases Study were included. Of them, 213 subjects (273 eyes) had POAG. All participants underwent standardised examinations. The independent and joint effects of IOP and myopia on POAG were examined using logistic regression models. Generalised estimating equation models were used to account for correlation between eyes. Higher IOP, longer axial length, and more negative spherical equivalent were independently associated with POAG, after adjusting for relevant covariates (all P ≤ 0.005). Significant interaction between IOP and myopia on POAG was observed (P interaction = 0.025). Eyes with moderate-to-high myopia (<−3.0 dioptres) with high IOP (≥20 mmHg) were 4.27 times (95% CI, 2.10–8.69) likely to have POAG, compared to eyes without myopia (>−0.5 dioptres) and with IOP <20 mmHg. Eyes with AL of ≥25.5 mm and high IOP (≥20 mmHg) were 16.22 times (95% CI, 7.73 to 34.03) likely to have POAG, compared to eyes with shorter AL (<23.5 mm) and lower IOP (<20 mmHg). These findings may provide additional insights into the pathophysiology of POAG and are particularly relevant for Asian populations. PMID:26758554

  15. Initial results of finger imaging using photoacoustic computed tomography

    NASA Astrophysics Data System (ADS)

    van Es, Peter; Biswas, Samir K.; Moens, Hein J. Bernelot; Steenbergen, Wiendelt; Manohar, Srirang

    2014-06-01

    We present a photoacoustic computed tomography investigation on a healthy human finger, to image blood vessels with a focus on vascularity across the interphalangeal joints. The cross-sectional images were acquired using an imager specifically developed for this purpose. The images show rich detail of the digital blood vessels with diameters between 100 μm and 1.5 mm in various orientations and at various depths. Different vascular layers in the skin including the subpapillary plexus could also be visualized. Acoustic reflections on the finger bone of photoacoustic signals from skin were visible in sequential slice images along the finger except at the location of the joint gaps. Not unexpectedly, the healthy synovial membrane at the joint gaps was not detected due to its small size and normal vascularization. Future research will concentrate on studying digits afflicted with rheumatoid arthritis to detect the inflamed synovium with its heightened vascularization, whose characteristics are potential markers for disease activity.

  16. Plasmonic "nano-fingers on nanowires" as SERS substrates.

    PubMed

    Sharma, Yashna; Dhawan, Anuj

    2016-05-01

    A surface-enhanced Raman scattering (SERS) substrate based on plasmonics-active metallic nano-finger arrays grown on arrays of triangular-shaped metal-coated silicon nanowire arrays is proposed. Finite-difference time-domain modeling is employed to numerically calculate the effect of the inter-finger gap and the growth angle of the nano-fingers on the magnitude of SERS enhancement and the plasmon resonance wavelength. Additionally, the polarization dependence of the SERS signals from these novel substrates has been studied. A protocol for the fabrication of the proposed SERS substrate is also discussed. PMID:27128080

  17. Bladder operated robotic joint

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A. (Inventor)

    1993-01-01

    This invention is a robotic joint which is operated by inflatable bladders and which can be used in applications where it is desired to move or hold an object. A support block supports an elongated plate to which is pivotally attached a finger. A tension strip passes over a lever attached to the finger and is attached at its ends to the support block on opposite sides of the plate. Bladders positioned between the plate and the tension strip on opposite sides of the plate can be inflated by pumps to pivot the finger, with one of the bladders being inflated while the other is being deflated.

  18. Repair of webbed fingers - slideshow

    MedlinePlus

    ... gov/ency/presentations/100096.htm Repair of webbed fingers - series—Normal anatomy To use the sharing features ... Health Solutions, Ebix, Inc. Related MedlinePlus Health Topics Finger Injuries and Disorders A.D.A.M., Inc. ...

  19. Spiral viscous fingering.

    NASA Astrophysics Data System (ADS)

    Nagatsu, Yuichiro; Hayashi, Atsushi; Kato, Yoshihito; Tada, Yutaka

    2006-11-01

    When a less-viscous fluid displaces a more-viscous fluid in a radial Hele-Shaw cell, viscous fingering pattern is believed to develop in a radial direction. We performed experiments on viscous fingering in a radial Hele-Shaw cell when a polymer solution, a sodium polyacrylate (SPA) solution is used as the more-viscous fluid and the trivalent iron (Fe^3+) solution is as the less-viscous fluid. The experiment was done by varying the concentration of Fe^3+, cFe3+. We have found that viscous fingering pattern develops spirally when cFe3+ is larger than a threshold value, while the pattern develops in a radial direction for small cFe3+. We confirmed from different experiments that an instantaneous chemical reaction takes place between SPA solution and Fe^3+ solution. The chemical reaction produces precipitation and significantly reduces the viscosity of the SPA solution. The quantity of the precipitation is increased with cFe3+. We will make a discussion on the relationship between the formation of spiral viscous fingering and the chemical reaction taking place between the two fluids.

  20. Tension Distribution in a Tendon-Driven Robotic Finger

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E. (Inventor); Platt, Robert (Inventor); Wampler, II, Charles W. (Inventor)

    2013-01-01

    A method is provided for distributing tension among tendons of a tendon-driven finger in a robotic system, wherein the finger characterized by n degrees of freedom and n+1 tendons. The method includes determining a maximum functional tension and a minimum functional tension of each tendon of the finger, and then using a controller to distribute tension among the tendons, such that each tendon is assigned a tension value less than the maximum functional tension and greater than or equal to the minimum functional tension. The method satisfies the minimum functional tension while minimizing the internal tension in the robotic system, and satisfies the maximum functional tension without introducing a coupled disturbance to the joint torques. A robotic system includes a robot having at least one tendon-driven finger characterized by n degrees of freedom and n+1 tendons, and a controller having an algorithm for controlling the tendons as set forth above.

  1. Safe Finger Tourniquet--Ideas.

    PubMed

    Wei, Lin-Gwei; Chen, Chieh-Feng; Hwang, Chun-Yuan; Chang, Chiung-Wen; Chiu, Wen-Kuan; Li, Chun-Chang; Wang, Hsian-Jenn

    2016-03-01

    Tourniquets are often needed for optimized phalangeal surgeries. However, few surgeons forget to remove them and caused ischemic injuries. We have a modified method to create a safe finger tourniquet for short duration finger surgeries, which can avoid such tragedy. It is done by donning a glove, cutting the tip of the glove over the finger of interest, and rolling the glove finger to the base. From 2010 to 2013, approximately 54 patients underwent digital surgical procedures with our safe finger tourniquet. Because the glove cannot be forgotten to be removed, the tourniquet must be released and removed. This is a simple and efficient way to apply a safe finger tourniquet by using hand rubber glove for a short-term bloodless finger surgery and can achieve an excellent surgical result. PMID:26855166

  2. Finger stiffness or edema as presenting symptoms of eosinophilic fasciitis.

    PubMed

    Suzuki, Shingo; Noda, Kazutaka; Ohira, Yoshiyuki; Shikino, Kiyoshi; Ikusaka, Masatomi

    2015-10-01

    To investigate the clinical features and finger symptoms of eosinophilic fasciitis (EF), we reviewed five patients with EF. The chief complaint was pain, edema and/or stiffness of the extremities. The distal extremities were affected in all patients, and there was also proximal involvement in one patient. One patient had asymmetrical symptoms. All four patients with upper limb involvement had limited range of motion of the wrist joints, and three of them complained of finger symptoms. Two of these three patients showed slight non-pitting edema of the hands, and the other one had subcutaneous induration of the forearm. All four patients with lower limb symptoms had limited range of motion of the ankle joints, and two showed edema or induration of the legs. Inflammatory changes in the joints were not detected in any of the patients. Two patients displayed neither objective induration nor edema, and two patients had muscle tenderness. In conclusion, finger symptoms of patients with EF might be caused by fasciitis of the forearms, which leads to dysfunction of the long finger flexors and extensors as well as slight edema of hands. Limited range of motion of wrist and/or ankle joints indicates sensitively distal muscle dysfunction caused by fasciitis. PMID:26248532

  3. Virtual three-dimensional blackboard: three-dimensional finger tracking with a single camera

    NASA Astrophysics Data System (ADS)

    Wu, Andrew; Hassan-Shafique, Khurram; Shah, Mubarak; da Vitoria Lobo, N.

    2004-01-01

    We present a method for three-dimensional (3D) tracking of a human finger from a monocular sequence of images. To recover the third dimension from the two-dimensional images, we use the fact that the motion of the human arm is highly constrained owing to the dependencies between elbow and forearm and the physical constraints on joint angles. We use these anthropometric constraints to derive a 3D trajectory of a gesticulating arm. The system is fully automated and does not require human intervention. The system presented can be used as a visualization tool, as a user-input interface, or as part of some gesture-analysis system in which 3D information is important.

  4. Response to reflected-force feedback to fingers in teleoperations

    NASA Technical Reports Server (NTRS)

    Sutter, P. H.; Iatridis, J. C.; Thakor, N. V.

    1989-01-01

    Reflected-force feedback is an important aspect of teleoperations. The objective is to determine the ability of the human operator to respond to that force. Telerobotics operation is simulated by computer control of a motor-driven device with capabilities for programmable force feedback and force measurement. A computer-controlled motor drive is developed that provides forces against the fingers as well as (angular) position control. A load cell moves in a circular arc as it is pushed by a finger and measures reaction forces on the finger. The force exerted by the finger on the load cell and the angular position are digitized and recorded as a function of time by the computer. Flexure forces of the index, long and ring fingers of the human hand in opposition to the motor driven load cell are investigated. Results of the following experiments are presented: (1) Exertion of maximum finger force as a function of angle; (2) Exertion of target finger force against a computer controlled force; and (3) Test of the ability to move to a target force against a force that is a function of position. Averaged over ten individuals, the maximum force that could be exerted by the index or long finger is about 50 Newtons, while that of the ring finger is about 40 Newtons. From the tests of the ability of a subject to exert a target force, it was concluded that reflected-force feedback can be achieved with the direct kinesthetic perception of force without the use of tactile or visual clues.

  5. Joint contribution to fingertip movement during a number entry task: an application of Jacobian matrix.

    PubMed

    Qin, Jin; Trudeau, Matthieu; Buchholz, Bryan; Katz, Jeffrey N; Xu, Xu; Dennerlein, Jack T

    2014-04-01

    Upper extremity kinematics during keyboard use is associated with musculoskeletal health among computer users; however, specific kinematics patterns are unclear. This study aimed to determine the dynamic roles of the shoulder, elbow, wrist and metacarpophalangeal (MCP) joints during a number entry task. Six subjects typed in phone numbers using their right index finger on a stand-alone numeric keypad. The contribution of each joint of the upper extremity to the fingertip movement during the task was calculated from the joint angle trajectory and the Jacobian matrix of a nine-degree-of-freedom kinematic representation of the finger, hand, forearm and upper arm. The results indicated that in the vertical direction where the greatest fingertip movement occurred, the MCP, wrist, elbow (including forearm) and shoulder joint contributed 10.2%, 55.6%, 27.7% and 6.5%, respectively, to the downward motion of the index finger averaged across subjects. The results demonstrated that the wrist and elbow contribute the most to the fingertip vertical movement, indicating that they play a major role in the keying motion and have a dynamic load beyond maintaining posture. PMID:24144858

  6. Formation of tough composite joints

    SciTech Connect

    Brun, M.K.

    1997-05-01

    Joints which exhibit tough fracture behavior were formed in a composite with a Si/SiC matrix reinforced with Textron SCS-6 fibers with either boron nitride or silicon nitride fiber coatings. In composites with BN coatings fibers were aligned uniaxially, while composites with Si{sub 3}N{sub 4}-coated fibers had a 0/90{degree} architecture. Lapped joints (joints with overlapping fingers) were necessary to obtain tough behavior. Geometrical requirements necessary to avoid brittle joint failure have been proposed. Joints with a simple overlap geometry (only a few fingers) would have to be very long in order to prevent brittle failure. Typical failure in these joints is caused by a crack propagating along the interfaces between the joint fingers. Joints of the same overall length, but with geometry changed to be symmetric about the joint centerline and with an extra shear surface exhibited tough fractures accompanied with extensive fiber pullout. The initial matrix cracking of these joints was relatively low because cracks propagated easily through the ends of the fingers. Joints with an optimized stepped sawtooth geometry produced composite-like failures with the stress/strain curves containing an elastic region followed by a region of rising stress with an increase of strain. Increasing the fiber/matrix interfacial strength from 9 to 25 MPa, by changing the fiber coating, increased matrix cracking and ultimate strength of the composite significantly. The best joints had matrix cracking stress and ultimate strength of 138 and 240 MPa, respectively. Joint failure was preceded by multiple matrix cracking in the entire composite. The high strength of the joints will permit building of structures containing joints with only a minor reduction of design stresses.

  7. Finger Forces in Clarinet Playing

    PubMed Central

    Hofmann, Alex; Goebl, Werner

    2016-01-01

    Clarinettists close and open multiple tone holes to alter the pitch of the tones. Their fingering technique must be fast, precise, and coordinated with the tongue articulation. In this empirical study, finger force profiles and tongue techniques of clarinet students (N = 17) and professional clarinettists (N = 6) were investigated under controlled performance conditions. First, in an expressive-performance task, eight selected excerpts from the first Weber Concerto were performed. These excerpts were chosen to fit in a 2 × 2 × 2 design (register: low–high; tempo: slow–fast, dynamics: soft–loud). There was an additional condition controlled by the experimenter, which determined the expression levels (low–high) of the performers. Second, a technical-exercise task, an isochronous 23-tone melody was designed that required different effectors to produce the sequence (finger-only, tongue-only, combined tongue-finger actions). The melody was performed in three tempo conditions (slow, medium, fast) in a synchronization-continuation paradigm. Participants played on a sensor-equipped Viennese clarinet, which tracked finger forces and reed oscillations simultaneously. From the data, average finger force (Fmean) and peak force (Fmax) were calculated. The overall finger forces were low (Fmean = 1.17 N, Fmax = 3.05 N) compared to those on other musical instruments (e.g., guitar). Participants applied the largest finger forces during the high expression level performance conditions (Fmean = 1.21 N). For the technical exercise task, timing and articulation information were extracted from the reed signal. Here, the timing precision of the fingers deteriorated the timing precision of the tongue for combined tongue-finger actions, especially for faster tempi. Although individual finger force profiles were overlapping, the group of professional players applied less finger force overall (Fmean = 0.54 N). Such sensor instruments provide useful insights into player

  8. Gert Finger Becomes Emeritus Physicist

    NASA Astrophysics Data System (ADS)

    de Zeeuw, T.; Lucuix, C.; Péron, M.

    2016-03-01

    Gert Finger has retired after almost 33 years service and he has been made the first Emeritus Physicist at ESO. An appreciation of some of his many achievements in the development of infrared instrumentation and detector controllers is given. A retirement party for Gert Finger was held in February 2016.

  9. Connective tissue adaptations in the fingers of performance sport climbers.

    PubMed

    Schreiber, Tonja; Allenspach, Philippe; Seifert, Burkhardt; Schweizer, Andreas

    2015-01-01

    This study investigates the changes of the connective tissue in the fingers of performance sport climbers resulting after a minimum of 15 years of climbing. Evaluation was performed by ultrasonography on the palmar side of the fingers (Dig) II-V to measure the thickness of the A2 and A4 annular pulleys, the flexor digitorum superficialis (FDS) and profundus (FDP) tendons and the palmar plates (PP's) of the proximal interphalangeal (PIP) as well as distal interphalangeal (DIP) joint in sagittal and axial direction. Totally, 31 experienced male sport climbers (mean age 37y, 30-48y grade French scale median 8b, range 7b+ to 9a+) participated in the study. The control-group consisted of 20 male non-climbers (age 37y, 30-51y). The A2 and A4 pulleys in climbers were all significantly thicker (A2 Dig III 62%, Dig IV 69%; A4 Dig III 69%, Dig IV 76%) as compared to non-climbers pulleys. All PP's of the DIP joints were also significantly thicker, particularly at Dig III and IV (76 and 67%), whereas the PP's at PIP joints were only scarce significant for three joints. Differences of the diameter of the flexor tendons were less distinct (1-21%) being significant only over the middle phalanx. High load to the fingers of rock climbers after a minimum of 15 years of climbing years induced considerable connective tissue adaptions in the fingers, most distinct at the flexor tendon pulleys and joint capsule (PP) of the DIP joints and well detectable by ultrasound. PMID:26267120

  10. A new approach to depict bone surfaces in finger imaging using photoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Biswas, S. K.; van Es, P.; Steenbergen, W.; Manohar, S.

    2015-03-01

    Imaging the vasculature close around the finger joints is of interest in the field of rheumatology. Locally increased vasculature in the synovial membrane of these joints can be a marker for rheumatoid arthritis. In previous work we showed that part of the photoacoustically induced ultrasound from the epidermis reflects on the bone surface within the finger. These reflected signals could be wrongly interpreted as new photoacoustic sources. In this work we show that a conventional ultrasound reconstruction algorithm, that considers the skin as a collection of ultrasound transmitters and the PA tomography probe as the detector array, can be used to delineate bone surfaces of a finger. This can in the future assist in the localization of the joint gaps. This can provide us with a landmark to localize the region of the inflamed synovial membrane. We test the approach on finger mimicking phantoms.

  11. Design of a Reconfigurable Robotic System for Flexoextension Fitted to Hand Fingers Size.

    PubMed

    Aguilar-Pereyra, J Felipe; Castillo-Castaneda, Eduardo

    2016-01-01

    Due to the growing demand for assistance in rehabilitation therapies for hand movements, a robotic system is proposed to mobilize the hand fingers in flexion and extension exercises. The robotic system is composed by four, type slider-crank, mechanisms that have the ability to fit the user fingers length from the index to the little finger, through the adjustment of only one link for each mechanism. The trajectory developed by each mechanism corresponds to the natural flexoextension path of each finger. The amplitude of the rotations for metacarpophalangeal joint (MCP) and proximal interphalangeal joint (PIP) varies from 0 to 90° and the distal interphalangeal joint (DIP) varies from 0 to 60°; the joint rotations are coordinated naturally. The four R-RRT mechanisms orientation allows a 15° abduction movement for index, ring, and little fingers. The kinematic analysis of this mechanism was developed in order to assure that the displacement speed and smooth acceleration into the desired range of motion and the simulation results are presented. The reconfiguration of mechanisms covers about 95% of hand sizes of a group of Mexican adult population. Maximum trajectory tracking error is less than 3% in full range of movement and it can be compensated by the additional rotation of finger joints without injury to the user. PMID:27524880

  12. Design of a Reconfigurable Robotic System for Flexoextension Fitted to Hand Fingers Size

    PubMed Central

    Castillo-Castaneda, Eduardo

    2016-01-01

    Due to the growing demand for assistance in rehabilitation therapies for hand movements, a robotic system is proposed to mobilize the hand fingers in flexion and extension exercises. The robotic system is composed by four, type slider-crank, mechanisms that have the ability to fit the user fingers length from the index to the little finger, through the adjustment of only one link for each mechanism. The trajectory developed by each mechanism corresponds to the natural flexoextension path of each finger. The amplitude of the rotations for metacarpophalangeal joint (MCP) and proximal interphalangeal joint (PIP) varies from 0 to 90° and the distal interphalangeal joint (DIP) varies from 0 to 60°; the joint rotations are coordinated naturally. The four R-RRT mechanisms orientation allows a 15° abduction movement for index, ring, and little fingers. The kinematic analysis of this mechanism was developed in order to assure that the displacement speed and smooth acceleration into the desired range of motion and the simulation results are presented. The reconfiguration of mechanisms covers about 95% of hand sizes of a group of Mexican adult population. Maximum trajectory tracking error is less than 3% in full range of movement and it can be compensated by the additional rotation of finger joints without injury to the user. PMID:27524880

  13. Biomechanical Analysis of the Human Finger Extensor Mechanism during Isometric Pressing

    PubMed Central

    Hu, Dan; Howard, David; Ren, Lei

    2014-01-01

    This study investigated the effects of the finger extensor mechanism on the bone-to-bone contact forces at the interphalangeal and metacarpal joints and also on the forces in the intrinsic and extrinsic muscles during finger pressing. This was done with finger postures ranging from very flexed to fully extended. The role of the finger extensor mechanism was investigated by using two alternative finger models, one which omitted the extensor mechanism and another which included it. A six-camera three-dimensional motion analysis system was used to capture the finger posture during maximum voluntary isometric pressing. The fingertip loads were recorded simultaneously using a force plate system. Two three-dimensional biomechanical finger models, a minimal model without extensor mechanism and a full model with extensor mechanism (tendon network), were used to calculate the joint bone-to-bone contact forces and the extrinsic and intrinsic muscle forces. If the full model is assumed to be realistic, then the results suggest some useful biomechanical advantages provided by the tendon network of the extensor mechanism. It was found that the forces in the intrinsic muscles (interosseus group and lumbrical) are significantly reduced by 22% to 61% due to the action of the extensor mechanism, with the greatest reductions in more flexed postures. The bone-to-bone contact force at the MCP joint is reduced by 10% to 41%. This suggests that the extensor mechanism may help to reduce the risk of injury at the finger joints and also to moderate the forces in intrinsic muscles. These apparent biomechanical advantages may be a result of the extensor mechanism's distinctive interconnected fibrous structure, through which the contraction of the intrinsic muscles as flexors of the MCP joint can generate extensions at the DIP and PIP joints. PMID:24732789

  14. Biomechanical analysis of the human finger extensor mechanism during isometric pressing.

    PubMed

    Hu, Dan; Howard, David; Ren, Lei

    2014-01-01

    This study investigated the effects of the finger extensor mechanism on the bone-to-bone contact forces at the interphalangeal and metacarpal joints and also on the forces in the intrinsic and extrinsic muscles during finger pressing. This was done with finger postures ranging from very flexed to fully extended. The role of the finger extensor mechanism was investigated by using two alternative finger models, one which omitted the extensor mechanism and another which included it. A six-camera three-dimensional motion analysis system was used to capture the finger posture during maximum voluntary isometric pressing. The fingertip loads were recorded simultaneously using a force plate system. Two three-dimensional biomechanical finger models, a minimal model without extensor mechanism and a full model with extensor mechanism (tendon network), were used to calculate the joint bone-to-bone contact forces and the extrinsic and intrinsic muscle forces. If the full model is assumed to be realistic, then the results suggest some useful biomechanical advantages provided by the tendon network of the extensor mechanism. It was found that the forces in the intrinsic muscles (interosseus group and lumbrical) are significantly reduced by 22% to 61% due to the action of the extensor mechanism, with the greatest reductions in more flexed postures. The bone-to-bone contact force at the MCP joint is reduced by 10% to 41%. This suggests that the extensor mechanism may help to reduce the risk of injury at the finger joints and also to moderate the forces in intrinsic muscles. These apparent biomechanical advantages may be a result of the extensor mechanism's distinctive interconnected fibrous structure, through which the contraction of the intrinsic muscles as flexors of the MCP joint can generate extensions at the DIP and PIP joints. PMID:24732789

  15. Fjords in viscous fingering: selection of width and opening scale

    SciTech Connect

    Mineev-weinstein, Mark; Ristroph, Leif; Thrasher, Matthew; Swinney, Harry

    2008-01-01

    Our experiments on viscous fingering of air into oil contained between closely spaced plates reveal two selection rules for the fjords of oil that separate fingers of air. (Fjords are the building blocks of solutions of the zero-surface-tension Laplacian growth equation.) Experiments in rectangular and circular geometries yield fjords with base widths {lambda}{sub c}/2, where {lambda}{sub c} is the most unstable wavelength from a linear stability analysis. Further, fjords open at an angle of 8.0{sup o}{+-}1.0{sup o}. These selection rules hold for a wide range of pumping rates and fjord lengths, widths, and directions.

  16. Effect of the Silver Content of SnAgCu Solder on the Interfacial Reaction and on the Reliability of Angle Joints Fabricated by Laser-Jet Soldering

    NASA Astrophysics Data System (ADS)

    Ji, Hongjun; Ma, Yuyou; Li, Mingyu; Wang, Chunqing

    2015-02-01

    The silver content of lead-free solders affects their microstructure, the interfacial reaction, and the performance of the joints in reliability tests. In this study, Sn3.0Ag0.5Cu (wt.%, SAC305) and Sn1.0Ag0.5Cu (wt.%, SAC105) solder balls of diameter 55 μm were reflowed on gold surface pads by laser-jet soldering. It was found that four types of layered intermetallic compound (IMC) were formed at the interfaces; these were Au5Sn/AuSn, AuSn, AuSn2, and AuSn4 from the pad side to the solder matrix. The Au5Sn/AuSn eutectic region, thickness 400 nm, formed because of the high cooling rate induced by the laser-jet soldering. During high-temperature storage tests, the silver became segregated at the interfaces between the Au-Sn IMC and the solder matrix, resulting in inhibition of IMC growth in SAC305 joints, the shear strengths of which were higher than those of SAC105 joints. In mechanical drop tests, however, percentage failure of the SAC305 joints was twice that of the SAC105 joints.

  17. Losing dexterity: patterns of impaired coordination of finger movements in musician’s dystonia

    PubMed Central

    Furuya, Shinichi; Tominaga, Kenta; Miyazaki, Fumio; Altenmüller, Eckart

    2015-01-01

    Extensive training can bring about highly-skilled action, but may also impair motor dexterity by producing involuntary movements and muscular cramping, as seen in focal dystonia (FD) and tremor. To elucidate the underlying neuroplastic mechanisms of FD, the present study addressed the organization of finger movements during piano performance in pianists suffering from the condition. Principal component (PC) analysis identified three patterns of fundamental joint coordination constituting finger movements in both patients and controls. The first two coordination patterns described less individuated movements between the “dystonic” finger and key-striking fingers for patients compared to controls. The third coordination pattern, representing the individuation of movements between the middle and ring fingers, was evident during a sequence of strikes with these fingers in controls, which was absent in the patients. Consequently, rhythmic variability of keystrokes was more pronounced during this sequence of strikes for the patients. A stepwise multiple-regression analysis further identified greater variability of keystrokes for individuals displaying less individuated movements between the affected and striking fingers. The findings suggest that FD alters dexterous joint coordination so as to lower independent control of finger movements, and thereby degrades fine motor control. PMID:26289433

  18. Hydrodynamic analysis of different finger positions in swimming: a computational fluid dynamics approach.

    PubMed

    Vilas-Boas, João Paulo; Ramos, Rui J; Fernandes, Ricardo J; Silva, António J; Rouboa, Abel I; Machado, Leandro; Barbosa, Tiago M; Marinho, Daniel A

    2015-02-01

    The aim of this research was to numerically clarify the effect of finger spreading and thumb abduction on the hydrodynamic force generated by the hand and forearm during swimming. A computational fluid dynamics (CFD) analysis of a realistic hand and forearm model obtained using a computer tomography scanner was conducted. A mean flow speed of 2 m · s(-1) was used to analyze the possible combinations of three finger positions (grouped, partially spread, totally spread), three thumb positions (adducted, partially abducted, totally abducted), three angles of attack (a = 0°, 45°, 90°), and four sweepback angles (y = 0°, 90°, 180°, 270°) to yield a total of 108 simulated situations. The values of the drag coefficient were observed to increase with the angle of attack for all sweepback angles and finger and thumb positions. For y = 0° and 180°, the model with the thumb adducted and with the little finger spread presented higher drag coefficient values for a = 45° and 90°. Lift coefficient values were observed to be very low at a = 0° and 90° for all of the sweepback angles and finger and thumb positions studied, although very similar values are obtained at a = 45°. For y = 0° and 180°, the effect of finger and thumb positions appears to be much most distinct, indicating that having the thumb slightly abducted and the fingers grouped is a preferable position at y = 180°, whereas at y = 0°, having the thumb adducted and fingers slightly spread yielded higher lift values. Results show that finger and thumb positioning in swimming is a determinant of the propulsive force produced during swimming; indeed, this force is dependent on the direction of the flow over the hand and forearm, which changes across the arm's stroke. PMID:25222969

  19. Ball-joint grounding ring

    NASA Technical Reports Server (NTRS)

    Aperlo, P. J. A.; Buck, P. A.; Weldon, V. A.

    1981-01-01

    In ball and socket joint where electrical insulator such as polytetrafluoroethylene is used as line to minimize friction, good electrical contact across joint may be needed for lightning protection or to prevent static-charge build-up. Electrical contact is maintained by ring of spring-loaded fingers mounted in socket. It may be useful in industry for cranes, trailers, and other applications requiring ball and socket joint.

  20. Simulation of light transport in arthritic- and non-arthritic human fingers

    NASA Astrophysics Data System (ADS)

    Milanic, Matija; Paluchowski, Lukasz A.; Randeberg, Lise L.

    2014-03-01

    Rheumatoid arthritis is a disease that frequently leads to joint destruction. It has high incidence rates worldwide, and the disease significantly reduces patient's quality of life due to pain, swelling and stiffness of the affected joints. Early diagnosis is necessary to improve course of the disease, therefore sensitive and accurate diagnostic tools are required. Optical imaging techniques have capability for early diagnosis and monitoring of arthritis. As compared to conventional diagnostic techniques optical technique is a noninvasive, noncontact and fast way of collecting diagnostic information. However, a realistic model of light transport in human joints is needed for understanding and developing of such optical diagnostic tools. The aim of this study is to develop a 3D numerical model of light transport in a human finger. The model will guide development of a hyperspectral imaging (HSI) diagnostic modality for arthritis in human fingers. The implemented human finger geometry is based on anatomical data. Optical data of finger tissues are adjusted to represent either an arthritic or an unaffected finger. The geometry and optical data serve as input into a 3D Monte Carlo method, which calculate diffuse reflectance, transmittance and absorbed energy distributions. The parameters of the model are optimized based on HIS-measurements of human fingers. The presented model serves as an important tool for understanding and development of HSI as an arthritis diagnostic modality. Yet, it can be applied to other optical techniques and finger diseases.

  1. Finger Tendon Travel Associated with Sequential Trigger Nail Gun Use

    PubMed Central

    Lowe, Brian; Albers, James; Hudock, Stephen; Krieg, Edward

    2015-01-01

    TECHNICAL ABSTRACT Background Pneumatic nail guns used in wood framing are equipped with one of two triggering mechanisms. Sequential actuation triggers have been shown to be a safer alternative to contact actuation triggers because they reduce traumatic injury risk. However, the sequential actuation trigger must be depressed for each individual nail fired as opposed to the contact actuation trigger, which allows the trigger to be held depressed as nails are fired repeatedly by bumping the safety tip against the workpiece. As such, concerns have been raised about risks for cumulative trauma injury, and reduced productivity, due to repetitive finger motion with the sequential actuation trigger. Purpose This study developed a method to predict cumulative finger flexor tendon travel associated with the sequential actuation trigger nail gun from finger joint kinematics measured in the trigger actuation and productivity standards for wood-frame construction tasks. Methods Finger motions were measured from six users wearing an instrumented electrogoniometer glove in a simulation of two common framing tasks–wall building and flat nailing of material. Flexor tendon travel was calculated from the ensemble average kinematics for an individual nail fired. Results Finger flexor tendon travel was attributable mostly to proximal interphalangeal and distal interphalangeal joint motion. Tendon travel per nail fired appeared to be slightly greater for a wall-building task than a flat nailing task. The present study data, in combination with construction industry productivity standards, suggest that a high-production workday would be associated with less than 60 m/day cumulative tendon travel per worker (based on 1700 trigger presses/day). Conclusion and Applications These results suggest that exposure to finger tendon travel from sequential actuation trigger nail gun use may be below levels that have been previously associated with high musculoskeletal disorder risk. PMID

  2. Finger-Circumference-Measuring Device

    NASA Technical Reports Server (NTRS)

    Le, Suy

    1995-01-01

    Easy-to-use device quickly measures circumference of finger (including thumb) on human hand. Includes polytetrafluoroethylene band 1/8 in. wide, bent into loop and attached to tab that slides on scale graduated in millimeters. Sliding tab preloaded with constant-force tension spring, which pulls tab toward closure of loop. Designed to facilitate measurements at various points along fingers to obtain data for studies of volumetric changes of fingers in microgravity. Also used in normal Earth gravity studies of growth and in assessment of diseases like arthritis.

  3. Fingering Instabilities in Dewetting Nanofluids

    NASA Astrophysics Data System (ADS)

    Pauliac-Vaujour, E.; Stannard, A.; Martin, C. P.; Blunt, M. O.; Notingher, I.; Moriarty, P. J.; Vancea, I.; Thiele, U.

    2008-05-01

    The growth of fingering patterns in dewetting nanofluids (colloidal solutions of thiol-passivated gold nanoparticles) has been followed in real time using contrast-enhanced video microscopy. The fingering instability on which we focus here arises from evaporatively driven nucleation and growth in a nanoscopically thin precursor solvent film behind the macroscopic contact line. We find that well-developed isotropic fingering structures only form for a narrow range of experimental parameters. Numerical simulations, based on a modification of the Monte Carlo approach introduced by Rabani et al. [Nature (London)NATUAS0028-0836 426, 271 (2003)10.1038/nature02087], reproduce the patterns we observe experimentally.

  4. Fingering instabilities in dewetting nanofluids.

    PubMed

    Pauliac-Vaujour, E; Stannard, A; Martin, C P; Blunt, M O; Notingher, I; Moriarty, P J; Vancea, I; Thiele, U

    2008-05-01

    The growth of fingering patterns in dewetting nanofluids (colloidal solutions of thiol-passivated gold nanoparticles) has been followed in real time using contrast-enhanced video microscopy. The fingering instability on which we focus here arises from evaporatively driven nucleation and growth in a nanoscopically thin precursor solvent film behind the macroscopic contact line. We find that well-developed isotropic fingering structures only form for a narrow range of experimental parameters. Numerical simulations, based on a modification of the Monte Carlo approach introduced by Rabani et al. [Nature (London) 426, 271 (2003)10.1038/nature02087], reproduce the patterns we observe experimentally. PMID:18518311

  5. Finger Forces in Clarinet Playing.

    PubMed

    Hofmann, Alex; Goebl, Werner

    2016-01-01

    Clarinettists close and open multiple tone holes to alter the pitch of the tones. Their fingering technique must be fast, precise, and coordinated with the tongue articulation. In this empirical study, finger force profiles and tongue techniques of clarinet students (N = 17) and professional clarinettists (N = 6) were investigated under controlled performance conditions. First, in an expressive-performance task, eight selected excerpts from the first Weber Concerto were performed. These excerpts were chosen to fit in a 2 × 2 × 2 design (register: low-high; tempo: slow-fast, dynamics: soft-loud). There was an additional condition controlled by the experimenter, which determined the expression levels (low-high) of the performers. Second, a technical-exercise task, an isochronous 23-tone melody was designed that required different effectors to produce the sequence (finger-only, tongue-only, combined tongue-finger actions). The melody was performed in three tempo conditions (slow, medium, fast) in a synchronization-continuation paradigm. Participants played on a sensor-equipped Viennese clarinet, which tracked finger forces and reed oscillations simultaneously. From the data, average finger force (F mean ) and peak force (F max ) were calculated. The overall finger forces were low (F mean = 1.17 N, F max = 3.05 N) compared to those on other musical instruments (e.g., guitar). Participants applied the largest finger forces during the high expression level performance conditions (F mean = 1.21 N). For the technical exercise task, timing and articulation information were extracted from the reed signal. Here, the timing precision of the fingers deteriorated the timing precision of the tongue for combined tongue-finger actions, especially for faster tempi. Although individual finger force profiles were overlapping, the group of professional players applied less finger force overall (F mean = 0.54 N). Such sensor instruments provide useful insights into player

  6. Review of Acute Traumatic Closed Mallet Finger Injuries in Adults

    PubMed Central

    Salazar Botero, Santiago; Hidalgo Diaz, Juan Jose; Benaïda, Anissa; Collon, Sylvie; Facca, Sybille

    2016-01-01

    In adults, mallet finger is a traumatic zone I lesion of the extensor tendon with either tendon rupture or bony avulsion at the base of the distal phalanx. High-energy mechanisms of injury generally occur in young men, whereas lower energy mechanisms are observed in elderly women. The mechanism of injury is an axial load applied to a straight digit tip, which is then followed by passive extreme distal interphalangeal joint (DIPJ) hyperextension or hyperflexion. Mallet finger is diagnosed clinically, but an X-ray should always be performed. Tubiana's classification takes into account the size of the bony articular fragment and DIPJ subluxation. We propose to stage subluxated fractures as stage III if the subluxation is reducible with a splint and as stage IV if not. Left untreated, mallet finger becomes chronic and leads to a swan-neck deformity and DIPJ osteoarthritis. The goal of treatment is to restore active DIPJ extension. The results of a six- to eight-week conservative course of treatment with a DIPJ splint in slight hyperextension for tendon lesions or straight for bony avulsions depends on patient compliance. Surgical treatments vary in terms of the approach, the reduction technique, and the means of fixation. The risks involved are stiffness, septic arthritis, and osteoarthritis. Given the lack of consensus regarding indications for treatment, we propose to treat all cases of mallet finger with a dorsal glued splint except for stage IV mallet finger, which we treat with extra-articular pinning. PMID:27019806

  7. Cross Gradient Based Joint Inversion of 2D Wide Angle Seismic Reflection/Refraction and Gravity Data Along the Profile Through the 2010 Ms 7.1 Yushu Earthquake, China

    NASA Astrophysics Data System (ADS)

    Xiang, S.; Zhang, H.

    2015-12-01

    2D wide-angle seismic reflection/refraction survey has been widely used to investigate crustal structure and Moho topography. Similarly gravity survey is also very important in the study of local and regional earth features. Seismic survey is sensitive to the seismic velocity parameters and interface variations. For gravity survey, it is sensitive to density parameters of the medium but the resolution along the vertical direction is relatively poor. In this study, we have developed a strategy to jointly invert for seismic velocity model, density model and interface positions using the gravity observations and seismic arrival times from different phases. For the joint inversion of seismic and gravity data, it often relies on the empirical relationship between seismic velocity and density. In comparison, our joint inversion strategy also includes the cross-gradient based structure constraint for seismic velocity and density models in addition to the empirical relationship between them. The objective function for the joint inversion includes data misfit terms for seismic travel times and gravity observations, the cross-gradient constraint, the smoothness terms for two models, and the data misfit term between predicted gravity data based on density model converted from velocity model using the empirical relationship. Each term has its respective weight. We have applied the new joint inversion method to the Riwoqe-Yushu-Maduo profile in northwest China. The profile crosses through the Qiangtang block and Bayan Har block from southwest to northeast, respectively. The 2010 Ms 7.1 Yushu earthquake is located on the profile, around the Ganzi-Yushu fault zone. The joint inversion produces the velocity and density models that are similar in structure and at the same time fit their respective data sets well. Compared to separate seismic inversion using seismic travel times, the joint inversion with gravity data gives a velocity model that better delineates the fault zones. Low

  8. Improving the fatigue resistance of adhesive joints in laminated wood structures

    NASA Technical Reports Server (NTRS)

    Laufenberg, Theodore L.; River, Bryan H.; Murmanis, Lidija L.; Christiansen, Alfred W.

    1988-01-01

    The premature fatigue failure of a laminated wood/epoxy test beam containing a cross section finger joint was the subject of a multi-disciplinary investigation. The primary objectives were to identify the failure mechanisms which occurred during the finger joint test and to provide avenues for general improvements in the design and fabrication of adhesive joints in laminated wood structures.

  9. Neural correlates of finger gnosis.

    PubMed

    Rusconi, Elena; Tamè, Luigi; Furlan, Michele; Haggard, Patrick; Demarchi, Gianpaolo; Adriani, Michela; Ferrari, Paolo; Braun, Christoph; Schwarzbach, Jens

    2014-07-01

    Neuropsychological studies have described patients with a selective impairment of finger identification in association with posterior parietal lesions. However, evidence of the role of these areas in finger gnosis from studies of the healthy human brain is still scarce. Here we used functional magnetic resonance imaging to identify the brain network engaged in a novel finger gnosis task, the intermanual in-between task (IIBT), in healthy participants. Several brain regions exhibited a stronger blood oxygenation level-dependent (BOLD) response in IIBT than in a control task that did not explicitly rely on finger gnosis but used identical stimuli and motor responses as the IIBT. The IIBT involved stronger signal in the left inferior parietal lobule (IPL), bilateral precuneus (PCN), bilateral premotor cortex, and left inferior frontal gyrus. In all regions, stimulation of nonhomologous fingers of the two hands elicited higher BOLD signal than stimulation of homologous fingers. Only in the left anteromedial IPL (a-mIPL) and left PCN did signal strength decrease parametrically from nonhomology, through partial homology, to total homology with stimulation delivered synchronously to the two hands. With asynchronous stimulation, the signal was stronger in the left a-mIPL than in any other region, possibly indicating retention of task-relevant information. We suggest that the left PCN may contribute a supporting visuospatial representation via its functional connection to the right PCN. The a-mIPL may instead provide the core substrate of an explicit bilateral body structure representation for the fingers that when disrupted can produce the typical symptoms of finger agnosia. PMID:24990921

  10. Rehabilitation for bilateral amputation of fingers

    USGS Publications Warehouse

    Stapanian, Martin A.; Stapanian, Adrienne M.P.; Staley, Keith E.

    2010-01-01

    We describe reconstructive surgeries, therapy, prostheses, and adaptations for a patient who experienced bilateral amputation of all five fingers of both hands through the proximal phalanges in January 1992. The patient made considerable progress in the use of his hands in the 10 mo after amputation, including nearly a 120% increase in the active range of flexion of metacarpophalangeal joints. In late 1992 and early 1993, the patient had "on-top plasty" surgeries, in which the index finger remnants were transferred onto the thumb stumps, performed on both hands. The increased web space and functional pinch resulting from these procedures made many tasks much easier. The patient and occupational therapists set challenging goals at all times. Moreover, the patient was actively involved in the design and fabrication of all prostheses and adaptations or he developed them himself. Although he was discharged from occupational therapy in 1997, the patient continues to actively find new solutions for prehension and grip strength 18 yr after amputation.

  11. Single Degree-of-Freedom Exoskeleton Mechanism Design for Finger Rehabilitation

    PubMed Central

    Wolbrecht, Eric T.; Reinkensmeyer, David J.; Perez-Gracia, Alba

    2014-01-01

    This paper presents the kinematic design of a single degree-of-freedom exoskeleton mechanism: a planar eight-bar mechanism for finger curling. The mechanism is part of a finger-thumb robotic device for hand therapy that will allow users to practice key pinch grip and finger-thumb opposition, allowing discrete control inputs for playing notes on a musical gaming interface. This approach uses the mechanism to generate the desired grasping trajectory rather than actuating the joints of the fingers and thumb independently. In addition, the mechanism is confined to the back of the hand, so as to allow sensory input into the palm of the hand, minimal size and apparent inertia, and the possibility of placing multiple mechanisms side-by-side to allow control of individual fingers. PMID:22275628

  12. Analysis of suitable geometrical parameters for designing a tendon-driven under-actuated mechanical finger

    NASA Astrophysics Data System (ADS)

    Penta, Francesco; Rossi, Cesare; Savino, Sergio

    2016-06-01

    This study aims to optimize the geometrical parameters of an under-actuated mechanical finger by conducting a theoretical analysis of these parameters. The finger is actuated by a flexion tendon and an extension tendon. The considered parameters are the tendon guide positions with respect to the hinges. By applying such an optimization, the correct kinematical and dynamical behavior of the closing cycle of the finger can be obtained. The results of this study are useful for avoiding the snapthrough and the single joint hyperflexion, which are the two breakdowns most frequently observed during experimentation on prototypes. Diagrams are established to identify the optimum values for the tendon guides position of a finger with specified dimensions. The findings of this study can serve as guide for future finger design.

  13. Systems for producing precise movements of a joint over a wide range of speeds and displacements for tests of a static-position sense.

    PubMed

    Clark, F J; Burgess, R C

    1987-03-01

    This report describes 3 types of apparatus that were used to produce precise movements of a joint over a wide range of speeds and angles. The designs feature an ability for ultra slow rotation of the joint (fractions of a degree per min) with a minimum of extraneous cues. Two designs use servo-controlled DC motors configured as velocity servos and a third design uses a galvanometer motor configured as a position servo. Originally designed for use with humans in studies of proprioception with the ankle and two joints of the index finger (the metacarpophalangeal joint and proximal interphalangeal joint), the apparatuses should be useful in a variety of applications where precise control of velocity and position is needed. PMID:3573811

  14. Multi-finger interaction during involuntary and voluntary single finger force changes

    PubMed Central

    Martin, J.R.; Zatsiorsky, V.M.; Latash, M.L.

    2011-01-01

    Two types of finger interaction are characterized by positive co-variation (enslaving) or negative co-variation (error compensation) of finger forces. Enslaving reflects mechanical and neural connections among fingers, while error compensation results from synergic control of fingers to stabilize their net output. Involuntary and voluntary force changes by a finger were used to explore these patterns. We hypothesized that synergic mechanisms will dominate during involuntary force changes, while enslaving will dominate during voluntary finger force changes. Subjects pressed with all four fingers to match a target force that was 10% of their maximum voluntary contraction (MVC). One of the fingers was unexpectedly raised 5.0 mm at a speed of 30.0 mm/s. During finger raising the subject was instructed “not to intervene voluntarily”. After the finger was passively lifted and a new steady-state achieved, subjects pressed down with the lifted finger, producing a pulse of force voluntarily. The data were analyzed in terms of finger forces and finger modes (hypothetical commands to fingers reflecting their intended involvement). The target finger showed an increase in force during both phases. In the involuntary phase, the target finger force changes ranged between 10.71 ± 1.89% MVC (I-finger) and 16.60 ± 2.26% MVC (L-finger). Generally, non-target fingers displayed a force decrease with a maximum amplitude of −1.49 ± 0.43% MVC (L-finger). Thus, during the involuntary phase, error compensation was observed – non-lifted fingers showed a decrease in force (as well as in mode magnitude). During the voluntary phase, enslaving was observed – non-target fingers showed an increase in force and only minor changes in mode magnitude. The average change in force of non-target fingers ranged from 21.83 ± 4.47% MVC for R-finger (M-finger task) to 0.71 ± 1.10 % MVC for L-finger (I-finger task). The average change in mode of non-target fingers was between −7.34 ± 19

  15. Formation of tough composite joints

    SciTech Connect

    Brun, M.K.

    1998-12-01

    Joints that exhibited tough fracture behavior were formed in a Si/SiC matrix reinforced with Textron SCS-6 fibers with either boron nitride or silicon nitride fiber coatings. Lapped joints (joints with overlapping fingers) were necessary to obtain tough behavior. Geometrical requirements necessary to avoid brittle joint failure were proposed. Joints with a simple overlap geometry (only a few fingers) had to be very long in order to prevent brittle failure. Joints with an optimized stepped sawtooth geometry produced composite-like failures with the stress/strain curves containing an elastic region followed by a region of rising stress with an increase of strain. Increasing the fiber/matrix interfacial strength, by changing the fiber coating, significantly increased matrix cracking and ultimate strength of the joints. The best joints had matrix cracking stress and ultimate strength of 138 and 240 MPa, respectively. Joint failure was preceded by multiple matrix cracking in the entire composite. The high strength of the joints should permit building of structures containing joints with only a minor reduction of design stresses.

  16. Prediction of Service Lives of Bridge Expansion Joints

    NASA Astrophysics Data System (ADS)

    Huang, Ying-Hua; Lin, Jing-Jhan

    2010-05-01

    This paper presents a service-life prediction model of expansion joints. Significant factors influencing the service lives of expansion joints were identified by statistical methods. Artificial neural network was implemented to establish the service-life prediction model of expansion joints. Taken finger plate joints for illustration, eight statistically significant factors influencing the service lives of finger plate joints are identified among twenty one factors studied. Through these eight factors, the service lives of expansion joints can be predicted by the established model. The training and testing errors indicate that the established artificial neural network model can provide accurate predictions which are essential information for maintenance strategies.

  17. [The mallet finger in children and adolescents].

    PubMed

    Schmidt, B; Weinberg, A; Friedrich, H

    2008-06-01

    The "mallet finger" in childhood and adolescence differs from the "mallet finger" in adults because of an open or gradually closing epiphysial plate. Thus, our results of conservative and operative treatment were evaluated particularly in consideration of an open growth plate. We analysed retrospectively the data of all patients who suffered a lesion at the extensor tendon insertion between 1996 and 2005 and were treated at our hospital. The coding was done according to age, sex, localisation, typing by Doyle, therapy and functional outcome. The typing by Doyle was extended through dividing type IV A into A1 (=Aitken I) and A2 (=Aitken II). Depending on extension deficits, the results were evaluated as very good (0 degrees ), medium (<15 degrees) and bad (>15 degrees). 76 patients, 45 boys and 31 girls aged 1 to 17 years (average age: 11.3) were studied. In consideration of the modified typing by Doyle, following distribution arose: type I (n=16), type II (n=14), type III (n=0), type IV A1 (n=17), type IV A2 (n=6), type IV B (n=21) and type IV C (n=2). A total of 50 patients was treated conservatively. Out of 26 operatively treated patients, 4 could be classified as type I, 12 as type II, 1 as type IV A1, 2 as type IV A2, 5 as type IV B, and 2 as type IV C. In 81.5 % of all patients no functional extension deficit was seen at the end of treatment; in patients treated conservatively, the percentage rate was 94 %. 6 patients, who were treated primarily operatively, showed poor functional outcome. 2 of these developed a suture track infection, in 2 cases chondral and osseous damage in the joint existed additionally, in one patient there was a comminuted fracture and in one patient a technical operative problem. Even in adolescence, conservative treatment of types I, IV A1 and A2, as well as IV B injuries is promising. A prerequisite is a consequent splint treatment and strict regular lateral X-ray control of the fracture fragment. At the beginning of treatment, we

  18. Giant cell tumours in fingers among the Inuit population in Greenland

    PubMed Central

    Duelund, Nick; Hougaard, Kjeld

    2016-01-01

    Objective Giant cell tumours (GCTs) of the tendon sheets in fingers are rare. We therefore find it of interest to report on 5 cases identified in the Inuit population in Greenland within 16 months prior to this study. Material and methods The Inuit account for 56,000 people of the total population in Greenland. From November 2010 to 16 months prior to this study, we diagnosed 5 cases (0.6% of all orthopaedic operations) with a GCT of the flexor tendon sheet of a finger. The patients were aged between 10 and 54 years, and 4 were women. All of them had noticed slow-growing tumours over 3 or more years and were referred for a suspected ganglion. Results In two cases, the tumour was located at the distal interphalangeal (DIP) joint in the thumb and in one case at the third finger. Two other patients had tumours at the metacarpophalangeal (MCP) joint of the third finger and the thumb, respectively; one of these two had a communicating tumour to the DIP joint. The last patient had two tumours on the same finger, one at the MCP joint and the other at the DIP joint. In one case, the tumour had also eroded the cortex of the first phalanx of the thumb, and the largest tumour measured 5 cm. Conclusion GCTs of the flexor tendon sheets in fingers are rare. It could be a coincidence that we have seen 5 cases within a short period of time. It is not possible to identify past cases through a register. A tumour in a finger is not the most common location for a ganglion, especially not at the DIP level. Therefore, a large tumour at this location is more likely to be a GCT. PMID:27052154

  19. Fluid mixing from viscous fingering.

    PubMed

    Jha, Birendra; Cueto-Felgueroso, Luis; Juanes, Ruben

    2011-05-13

    Mixing efficiency at low Reynolds numbers can be enhanced by exploiting hydrodynamic instabilities that induce heterogeneity and disorder in the flow. The unstable displacement of fluids with different viscosities, or viscous fingering, provides a powerful mechanism to increase fluid-fluid interfacial area and enhance mixing. Here we describe the dissipative structure of miscible viscous fingering, and propose a two-equation model for the scalar variance and its dissipation rate. Our analysis predicts the optimum range of viscosity contrasts that, for a given Péclet number, maximizes interfacial area and minimizes mixing time. In the spirit of turbulence modeling, the proposed two-equation model permits upscaling dissipation due to fingering at unresolved scales. PMID:21668165

  20. Implementation of Robot Finger Using Shape Memory Alloys and Electrical Motors

    NASA Astrophysics Data System (ADS)

    Terauchi, Mina; Zenba, Kota; Shimada, Akira

    This paper introduces a mechanical structure and control technique of a second robot finger as a system integration. The finger has been developed as element of a robot hand which has 20 joints and 16 degrees of freedom in order to express fingerspelling. The first joint of the finger is driven by small DC servo motor and the second and third joints are driven by shape-memory alloy (SMA) wires. The hand system consists of four parts of “hand mechanism”, “drive device”, “control unit” and “man-machine interface”. In order to implement cooperative smooth motions, the control system is designed based on experimental results related to system identification, and the position trajectory refernce is designed considering time delay on the SMA. Finally, we report the simulation and experimental control results to evaluate the presented system.

  1. Modification of the Internal Suture Technique for Mallet Finger

    PubMed Central

    Jiang, Bo; Wang, Peiji; Zhang, Yong; Zhao, Jiaju; Dong, Qirong

    2015-01-01

    Abstract This article describes a treatment of tendinous mallet finger deformities using a modified internal suture technique for the stable fixation of the terminal extensor tendon and bone. Between March 2011 and July 2013, 15 patients with mallet fingers who had been treated using this modification were included in this study. The patients included 10 men and 5 women with a mean age of 33 years (range, 19–50 years). Of these patients, 9 had chronic mallet fingers, 3 were unable to comply with a splinting regimen, and 3 had a history of unsuccessful splinting therapy. The mean time between the injury and surgery was 5.5 months (range, 1–15 months). We graded the results using Crawford criteria. The mean follow-up period was 12 months (range, 9–16 months). The mean final active range of motion of the distal interphalangeal joint flexion was 73° (range, 60°–90°). Based on Crawford evaluation criteria, 8 patients were graded as excellent, 6 were graded as good, and 1 was graded as fair. Apart from 2 documented mild nail deformities, no complications were encountered. This modified technique should be considered for the management of a tendinous mallet finger deformity when the internal suture technique is planned. PMID:25674757

  2. Rolling-Convolute Joint For Pressurized Glove

    NASA Technical Reports Server (NTRS)

    Kosmo, Joseph J.; Bassick, John W.

    1994-01-01

    Rolling-convolute metacarpal/finger joint enhances mobility and flexibility of pressurized glove. Intended for use in space suit to increase dexterity and decrease wearer's fatigue. Also useful in diving suits and other pressurized protective garments. Two ring elements plus bladder constitute rolling-convolute joint balancing torques caused by internal pressurization of glove. Provides comfortable grasp of various pieces of equipment.

  3. Long-finger pollicization for macrodactyly of the thumb and index finger.

    PubMed

    Donohue, Kenneth W; Zlotolow, Dan A; Kozin, Scott H

    2014-01-01

    Pollicization of the long finger is rarely performed, and previously described for treating traumatic thumb and index finger loss. Because the long finger lacks the independence of motion and muscular attachments of the index finger, pollicization of the long finger requires modifications of the technique. We present the case of a 3-year-old girl with progressive macrodactyly of the thumb and index finger associated with a lipofibromatous hamartoma of the median nerve. The involved digits were severely enlarged, stiff, and nonfunctional. The child was treated with first and second ray resection followed by long-finger pollicization. Surgical pearls and pitfalls are discussed. PMID:24919138

  4. What's Your Angle on Angles?

    ERIC Educational Resources Information Center

    Browning, Christine A.; Garza-Kling, Gina; Sundling, Elizabeth Hill

    2007-01-01

    Although the nature of the research varies, as do concepts of angle, research in general supports the supposition that angle is a complex idea, best understood from a variety of perspectives. In fact, the concept of angle tends to be threefold, consisting of: (1) the traditional, static notion of two rays meeting at a common vertex; (2) the idea…

  5. From viscous fingering to bulk elastic fingering in soft materials

    NASA Astrophysics Data System (ADS)

    Saintyves, Baudouin; Biggins, John; Wei, Zhiyan; Mora, Serge; Dauchot, Olivier; Mahadevan, L.; Bouchaud, Elisabeth

    2014-03-01

    Systematic experiments have been performed in purely elastic polyacrylamide gels in Hele-Shaw cells. We have shown that a bulk fingering instability arises in the highly deformable confined elastomers. It shares some similarities with the famous Saffman-Taylor instability, but a systematic study shows that surface tension is not relevant. This instability is sub-critical, with a clear hysteretic behavior. Our experimental observations have been compared very favorably to theoretical and finite element simulations results. In particular, the instability wavelength and the critical front advance have been shown to be proportional to the distance between the two glass plates constituting the cell. We have also shown that in Maxwell viscoelastic fluids, one crosses over continuously from a viscous to an elastic fingering instability.

  6. Development of a finger biomechanical model and its considerations.

    PubMed

    Fok, Kim Seng; Chou, Siaw Meng

    2010-03-01

    The development of a biomechanical model for a human finger is faced with many challenges, such as extensor mechanism complexity, statistical indeterminacy and suitability of computational processes. Motivation for this work was to develop a computer model that is able to predict the internal loading patterns of tendons and joint surfaces experienced by the human finger, while mitigating these challenges. Proposed methodology was based on a non-linear optimising mathematical technique with a criterion of boundary conditions and equality equations, maximised against unknown parameters to reduce statistical indeterminacy. Initial validation was performed via the simulation of one dynamic and two static postures case studies. Past models and experiments were used, based on published literature, to verify the proposed model's methodology and results. The feasibility of the proposed methodology was deemed satisfactory as the simulated results were concordant with in-vivo results for the extrinsic flexors. PMID:19962148

  7. Surgical treatment of degenerative osteoarthritis of the fingers.

    PubMed

    Rongières, M

    2013-09-01

    Degenerative osteoarthritis of the long fingers is rare and surgical management is often necessary if there is joint pain, however this indication should not only be based on radiographic imaging. The specific anatomical problems of the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints are described. The surgical approach for each joint is described as well as functional management, in particular that of the extensor apparatus. Mobility should always be preserved for the MCP, arthroplasties are recommended for the PIP except for the index, and arthrodesis for the DIP. The different and most frequently used implants are described as well as the indications and expected results. The indications are discussed in relation to the limited results in the literature as well as the preferences of a panel of French hand surgeons. PMID:23684245

  8. Silicone Arthroplasty After Ankylosis of Proximal Interphalangeal Joints in Rheumatoid Arthritis: A Case Report.

    PubMed

    Awan, Hisham M; Imbriglia, Joseph E

    2016-01-01

    Rheumatoid arthritis (RA) can cause severe disability of the hand and fingers. Ankylosis of the finger joints is a known yet underreported manifestation of RA of the hand. We report the case of a patient who had RA and developed autofusion of the proximal interphalangeal (PIP) joints. At presentation, the PIP joints were fused in 15° of flexion. Silicone PIP arthroplasty was performed. Function improved with 60° of PIP joint motion and no pain. PMID:27327930

  9. Mechanical model of a single tendon finger

    NASA Astrophysics Data System (ADS)

    Rossi, Cesare; Savino, Sergio

    2013-10-01

    The mechanical model of a single tendon three phalanxes finger is presented. By means of the model both kinematic and dynamical behavior of the finger itself can be studied. This finger is a part of a more complex mechanical system that consists in a four finger grasping device for robots or in a five finger human hand prosthesis. A first prototype has been realized in our department in order to verify the real behavior of the model. Some results of both kinematic and dynamical behavior are presented.

  10. Optimize design dexterity of tooth-arrangement three-fingered hands

    NASA Astrophysics Data System (ADS)

    Wang, Hai-ying; Zhang, Li-yong; Zhang, Yong-de

    2005-12-01

    "Tooth-arrangement Three-fingered Hands" is a brand-new oral cavity repairing robot. It has the functions of fine grasping and arranging artificial tooth, manufacturing complete denture, etc. A new optimization design method is proposed in this paper that solves the problems in optimization structure parameter confirming and optimal dexterous design. The bionic theorem behind duplicating the dexterity of the human finger is incorporated into the structure parameter optimization algorithm. Through analyzing the dexterity of the single finger, adopting the design criteria of dexterous degree with optimum index and combining the characteristic of grasping the smallest object, this design method can confirm the best dexterity area for single finger, relations between every rod length and rotation range of every joint. Using MATLAB optimization toolbox to optimize above-mentioned structure parameter, it gains the optimal dimension that meets characteristic of human fingers and can finish grasping. A quantitative method is also proposed in this paper to calculate the relative position between fingers. It is applied to the real design of Tooth-Arrangement Three-fingered Hands and obtained optimal flexible performance.