scholarly journals Selective activation of Forearm muscles for improving Wrist Joint Stability

2021 ◽  
Vol 1084 (1) ◽  
pp. 012025
Author(s):  
A Arulkumar ◽  
P Babu
1992 ◽  
Vol 114 (2) ◽  
pp. 162-169 ◽  
Author(s):  
R. H. Nathan

The isometric forces and moments generated at the hand segment by thirteen of the forearm muscles were measured on three test subjects. Small bipolar surface electrodes were used to activate each muscle separately. The direction of the force vector generated at the fingertips and the percentage torque generated about the longitudinal axis of the hand segment were measured and were modeled for one subject as a parabolic function of the position of the wrist and radioulnar joints in their ranges of motion. The results exhibited a high standard deviation. It is proposed that a significant component of this standard deviation is inherent in the biomechanics of the musculo-skeletal system. Variations in the test protocol were used to test this hypothesis. The standard deviation was found to be significantly larger in the flexor muscles than the extensors. It was concluded that the stability and elasticity of the soft tissue structures in the region of the wrist joint may significantly influence the direction of the generated joint moment vector.


2014 ◽  
Vol 30 (2) ◽  
pp. 282-289 ◽  
Author(s):  
Michael W.R. Holmes ◽  
Peter J. Keir

Understanding joint stiffness and stability is beneficial for assessing injury risk. The purpose of this study was to examine joint rotational stiffness for individual muscles contributing to elbow joint stability. Fifteen male participants maintained combinations of three body orientations (standing, supine, sitting) and three hand preloads (no load, solid tube, fluid filled tube) while a device imposed a sudden elbow extension. Elbow angle and activity from nine muscles were inputs to a biomechanical model to determine relative contributions to elbow joint rotational stiffness, reported as percent of total stiffness. A body orientation by preload interaction was evident for most muscles (P< .001). Brachioradialis had the largest change in contribution while standing (no load, 18.5%; solid, 23.8%; fluid, 26.3%). Across trials, the greatest contributions were brachialis (30.4 ± 1.9%) and brachioradialis (21.7 ± 2.2%). Contributions from the forearm muscles and triceps were 5.5 ± 0.6% and 9.2 ± 1.9%, respectively. Contributions increased at time points closer to the perturbation (baseline to anticipatory), indicating increased neuromuscular response to resist rotation. This study quantified muscle contributions that resist elbow perturbations, found that forearm muscles contribute marginally and showed that orientation and preload should be considered when evaluating elbow joint stiffness and safety.


Author(s):  
Byunghee Hwang ◽  
Tae-Il Kim ◽  
Hyunjin Kim ◽  
Sungjin Jeon ◽  
Yongdoo Choi ◽  
...  

A ubiquinone-BODIPY photosensitizer self-assembles into nanoparticles (PS-Q-NPs) and undergoes selective activation within the highly reductive intracellular environment of tumors, resulting in “turn-on” fluorescence and photosensitizing activities.


2006 ◽  
Vol 11 (6) ◽  
pp. 4-7
Author(s):  
Charles N. Brooks ◽  
Richard E. Strain ◽  
James B. Talmage

Abstract The primary function of the acetabular labrum, like that of the glenoid, is to deepen the socket and improve joint stability. Tears of the acetabular labrum are common in older adults but occur in all age groups and with equal frequency in males and females. The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fifth Edition, is silent about rating tears, partial or complete excision, or repair of the acetabular labrum. Provocative tests to detect acetabular labrum tears involve hip flexion and rotation; all rely on production of pain in the groin (typically), clicking, and/or locking with passive or active hip motions. Diagnostic tests or procedures rely on x-rays, conventional arthrography, computerized tomography, magnetic resonance imaging (MRI), magnetic resonance arthrography (MRA), and hip arthroscopy. Hip arthroscopy is the gold standard for diagnosis but is the most invasive and most likely to result in complications, and MRA is about three times more sensitive and accurate in detecting acetabular labral tears than MRI alone. Surgical treatment for acetabular labrum tears usually consists of arthroscopic debridement; results tend to be better in younger patients. In general, an acetabular labral tear, partial labrectomy, or labral repair warrants a rating of 2% lower extremity impairment. Evaluators should avoid double dipping (eg, using both a Diagnosis-related estimates and limited range-of-motion tests).


2015 ◽  
Vol 04 (S 02) ◽  
Author(s):  
M. Rizzo ◽  
A. Hooke ◽  
K. An ◽  
W. Cooney

1992 ◽  
Vol 05 (04) ◽  
pp. 158-162 ◽  
Author(s):  
D. Blackketter ◽  
J Harari ◽  
J. Dupuis

Bone/lateral collateral ligament/bone preparations were tested and structural mechanical properties compared to properties of cranial cruciate ligament in 15 dogs. The lateral collateral ligament has sufficient stiffness to provide stifle joint stability and strength to resist acute overload following fibular head transposition.


2002 ◽  
Vol 715 ◽  
Author(s):  
Zhi-Feng Huang ◽  
Rashmi C. Desai

AbstractThe morphological and compositional instabilities in the heteroepitaxial strained alloy films have attracted intense interest from both experimentalists and theorists. To understand the mechanisms and properties for the generation of instabilities, we have developed a nonequilibrium, continuum model for the dislocation-free and coherent film systems. The early evolution processes of surface pro.les for both growing and postdeposition (non-growing) thin alloy films are studied through a linear stability analysis. We consider the coupling between top surface of the film and the underlying bulk, as well as the combination and interplay of different elastic effects. These e.ects are caused by filmsubstrate lattice misfit, composition dependence of film lattice constant (compositional stress), and composition dependence of both Young's and shear elastic moduli. The interplay of these factors as well as the growth temperature and deposition rate leads to rich and complicated stability results. For both the growing.lm and non-growing alloy free surface, we determine the stability conditions and diagrams for the system. These show the joint stability or instability for film morphology and compositional pro.les, as well as the asymmetry between tensile and compressive layers. The kinetic critical thickness for the onset of instability during.lm growth is also calculated, and its scaling behavior with respect to misfit strain and deposition rate determined. Our results have implications for real alloy growth systems such as SiGe and InGaAs, which agree with qualitative trends seen in recent experimental observations.


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