Prediction of Ligament Length During Wrist Flexion Extension

2008 ◽  
Author(s):  
Rita M. Patterson ◽  
Naoya Yazaki ◽  
Clark R. Andersen ◽  
Newt H. Scott ◽  
Steven F. Viegas
Keyword(s):  
Direct Measurement ◽  
High Precision ◽  
Carpal Bones ◽  
Short Length ◽  
Ligament Length ◽  
Wrist Flexion ◽  
Wrist Motion ◽  
Flexion Extension ◽  
Carpal Ligaments ◽  
Precision Motion

Direct measurement of ligament length in the wrist is difficult due to constrained space and short length of many ligaments. No prior studies have reported measurements of ligament length between the carpal bones of the wrist. In this presentation, we have combined high precision motion analysis of the carpal bones, subsequent manual digitization of the ligament attachment regions, and a simulated ligament wrapping model, to generate predictions of carpal ligaments’ length and implied strain during wrist motion.

scholarly journals Design of Shape Memory Alloy-Based Soft Wearable Robot for Assisting Wrist Motion

2019 ◽  
Vol 9 (19) ◽  
pp. 4025 ◽  
Author(s):  
Jaeyeon Jeong ◽  
Ibrahim Bin Yasir ◽  
Jungwoo Han ◽  
Cheol Hoon Park ◽  
Soo-Kyung Bok ◽  
...  
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Degrees Of Freedom ◽  
Wrist Flexion ◽  
Wearable Robot ◽  
Maximum Torque ◽  
Wrist Motion ◽  
Contraction Ratio ◽  
Flexion Extension ◽  
The Average Range

In this paper, we propose a shape memory alloy (SMA)-based wearable robot that assists the wrist motion for patients who have difficulties in manipulating the lower arm. Since SMA shows high contraction strain when it is designed as a form of coil spring shape, the proposed muscle-like actuator was designed after optimizing the spring parameters. The fabricated actuator shows a maximum force of 10 N and a maximum contraction ratio of 40%. The SMA-based wearable robot, named soft wrist assist (SWA), assists 2 degrees of freedom (DOF) wrist motions. In addition, the robot is totally flexible and weighs 151g for the wearable parts. A maximum torque of 1.32 Nm was measured for wrist flexion, and a torque of larger than 0.5 Nm was measured for the other motions. The robot showed the average range of motion (ROM) with 33.8, 30.4, 15.4, and 21.4 degrees for flexion, extension, ulnar, and radial deviation, respectively. Thanks to the soft feature of the SWA, time cost for wearing the device is shorter than 2 min as was also the case for patients when putting it on by themselves. From the experimental results, the SWA is expected to support wrist motion for diverse activities of daily living (ADL) routinely for patients.

scholarly journals Carpal Pronation and Supination Changes in the Unstable Wrist

2018 ◽  
Vol 07 (04) ◽  
pp. 298-302
Author(s):  
Walter Short ◽  
Frederick Werner
Keyword(s):  
Clinical Relevance ◽  
Wrist Flexion ◽  
New Techniques ◽  
Interosseous Ligament ◽  
Wrist Motion ◽  
Extensor Carpi Ulnaris ◽  
Flexion Extension ◽  
Before And After ◽  
Dart Throwing ◽  
Throwing Motion

Background Little is known about changes in scaphoid and lunate supination and pronation following scapholunate interosseous ligament (SLIL) injury. Information on these changes may help explain why some SLIL reconstructions have failed and help in the development of new techniques. Purpose To determine if following simulated SLIL injury there was an increase in scaphoid pronation and lunate supination and to determine if concurrently there was an increase in the extensor carpi ulnaris (ECU) force. Materials and Methods Scaphoid and lunate motion were measured before and after sectioning of the SLIL and two volar ligaments in 22 cadaver wrists, and before and after sectioning of the SLIL and two dorsal ligaments in 15 additional wrists. Each wrist was dynamically moved through wrist flexion/extension, radioulnar deviation, and a dart-throwing motion. Changes in the ECU force were recorded during each wrist motion. Results Scaphoid pronation and lunate supination significantly increased following ligamentous sectioning during each motion. There were significant differences in the amount of change in lunate motion, but not in scaphoid motion, between the two groups of sectioned ligaments. Greater percentage ECU force was required following ligamentous sectioning to achieve the same wrist motions. Conclusion Carpal supination/pronation changed with simulated damage to the scapholunate stabilizers. This may be associated with the required increases in the ECU force. Clinical Relevance In reconstructing the SLIL, one should be aware of the possible need to correct scaphoid pronation and lunate supination that occur following injury. This may be more of a concern when the dorsal stabilizers are injured.

Scaphoid Motion of the Wrist with Scapho-trapezio-trapezoidal Osteoarthritis-A Pilot Study

2020 ◽  
Vol 16 (3) ◽  
pp. 206-209
Author(s):  
Ronit Wollstein ◽  
Hisao Moritomo ◽  
Iida Akio ◽  
Shohei Omokawa
Keyword(s):  
Neutral Position ◽  
Wrist Flexion ◽  
Wrist Movement ◽  
Ulnar Deviation ◽  
Wrist Motion ◽  
3 Dimensional ◽  
Active Flexion ◽  
Extended Position ◽  
Flexion Extension ◽  
Surface Models

Background: The purpose of this study was to investigate scaphoid motion within the scapho-trapezio-trapezoidal (STT) joint during wrist motion in the presence of STT joint osteoarthritis (OA). Methods: We studied 11 wrists with STT OA and 5 normal wrists. Computed tomography (CT) images were acquired in five wrist positions (maximum active flexion, extension, radial deviation, ulnar deviation, and neutral position). The 3-dimensional surface models of the radius and scaphoid were constructed and the motion of scaphoid relative to the radius was calculated. Results and Conclusion: During wrist flexion/extension motion, the scaphoid rotated mostly in the flexion/extension plane. The angle tended to be smaller in STT OA than in normal. During wrist radioulnar deviation, the scaphoid was in an extended position in neutral wrist in STT OA. The motion of scaphoid in STT OA was divided into two types: a rigid type and mobile type. The mobile type rotated closer to the flexion/extension plane than the rigid type. Taking into account scaphoid motion during wrist movement before surgery may provide better results in the treatment of STT OA.

scholarly journals Design and Development of Continuous Passive Motion (CPM) for Fingers and Wrist Grounded-Exoskeleton Rehabilitation System

2021 ◽  
Vol 11 (2) ◽  
pp. 815
Author(s):  
Husam Almusawi ◽  
Géza Husi
Keyword(s):  
Experimental Testing ◽  
Hand Movement ◽  
Evaluation Process ◽  
Continuous Passive Motion ◽  
Wrist Flexion ◽  
Design And Development ◽  
Passive Motion ◽  
Assistive Robots ◽  
Flexion Extension ◽  
Design Characteristics

Impairments of fingers, wrist, and hand forearm result in significant hand movement deficiencies and daily task performance. Most of the existing rehabilitation assistive robots mainly focus on either the wrist training or fingers, and they are limiting the natural motion; many mechanical parts associated with the patient’s arms, heavy and expensive. This paper presented the design and development of a new, cost-efficient Finger and wrist rehabilitation mechatronics system (FWRMS) suitable for either hand right or left. The proposed machine aimed to present a solution to guide individuals with severe difficulties in their everyday routines for people suffering from a stroke or other motor diseases by actuating seven joints motions and providing them repeatable Continuous Passive Motion (CPM). FWRMS approach uses a combination of; grounded-exoskeleton structure to provide the desired displacement to the hand’s four fingers flexion/extension (F/E) driven by an indirect feed drive mechanism by adopting a leading screw and nut transmission; and an end-effector structure to provide angular velocity to the wrist flexion/ extension (F/E), wrist radial/ulnar deviation (R/U), and forearm supination/pronation (S/P) driven by a rotational motion mechanism. We employed a single dual-sided actuator to power both mechanisms. Additionally, this article presents the implementation of a portable embedded controller. Moreover, this paper addressed preliminary experimental testing and evaluation process. The conducted test results of the FWRMS robot achieved the required design characteristics and executed the motion needed for the continuous passive motion rehabilitation and provide stable trajectories guidance by following the natural range of motion (ROM) and a functional workspace of the targeted joints comfortably for all trainable movements by FWRMS.

Ultra‐Sensitive and Stretchable Ionic Skins for High‐Precision Motion Monitoring

2021 ◽  
pp. 2010199
Author(s):  
Jeong Hui Kim ◽  
Kyung Gook Cho ◽  
Dae Hyun Cho ◽  
Kihyon Hong ◽  
Keun Hyung Lee
Keyword(s):  
High Precision ◽  
Precision Motion

scholarly journals Compensation of Hysteresis in Hybrid Reluctance Actuator for High-Precision Motion

2019 ◽  
Vol 52 (15) ◽  
pp. 477-482 ◽  
Author(s):  
Francesco Cigarini ◽  
Shingo Ito ◽  
Julian Konig ◽  
Andreas Sinn ◽  
Georg Schitter
Keyword(s):  
High Precision ◽  
Precision Motion

Quantification of Hand Grip Force under Dynamic Conditions

1993 ◽  
Vol 37 (10) ◽  
pp. 715-719 ◽  
Author(s):  
Katherine R. Lehman ◽  
W. Gary Allread ◽  
P. Lawrence Wright ◽  
William S. Marras
Keyword(s):  
Grip Force ◽  
Wrist Flexion ◽  
Range Of Movement ◽  
Ulnar Deviation ◽  
Dynamic Conditions ◽  
Radial Deviation ◽  
Hand Grip ◽  
Flexion Extension ◽  
Maximum Grip ◽  
Lower Grip

A laboratory experiment was conducted to determine whether grip force capabilities are lower when the wrist is moved than in a static position. The purpose was to determine the wrist velocity levels and wrist postures that had the most significant effect on grip force. Maximum grip forces of five male and five female subjects were determined under both static and dynamic conditions. The dominant wrist of each subject was secured to a CYBEX II dynamometer and grip force was collected during isokinetic wrist deviations for four directions of motion (flexion to extension, extension to flexion, radial to ulnar, and ulnar to radial). Six different velocity levels were analyzed and grip forces were recorded at specific wrist positions throughout each range of movement. For flexion-extension motions, wrist positions from 45 degrees flexion to 45 degrees extension were analyzed whereas positions from 20 degrees radial deviation to 20 degrees ulnar deviation were studied for radial-ulnar activity. Isometric exertions were also performed at each desired wrist position. Results showed that, for all directions of motion, grip forces for all isokinetic conditions were significantly lower than for the isometric exertions. Lower grip forces were exhibited at extreme wrist flexion and extreme radial and ulnar positions for both static and dynamic conditions. The direction of motion was also found to affect grip strength; extension to flexion exertions produced larger grip forces than flexion to extension exertions and radial to ulnar motion showed larger grip forces than ulnar to radial deviation. Although, males produced larger grip forces than females in all exertions, significant interactions between gender and velocity were noted.

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