scholarly journals Shoulder muscle weakness effects on muscle hardness around the shoulder joint and scapulae

2020 ◽  
Vol 5 (1) ◽  
pp. 001-007
Author(s):  
Atsushi Kubota ◽  
Chiho Takayanagi ◽  
Kohei Kishimoto
Keyword(s):  
Muscle Weakness ◽  
Shoulder Joint ◽  
Shoulder Muscle ◽  
Muscle Hardness

scholarly journals Cadaveric evaluation of the feasibility of glenohumeral joint denervation

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Amr M. Aly
Keyword(s):  
Muscle Weakness ◽  
Shoulder Joint ◽  
Glenohumeral Joint ◽  
Axillary Nerve ◽  
Low Risk ◽  
Dorsal Approach ◽  
Articular Branch ◽  
Pectoral Nerve ◽  
Teres Minor

Abstract Purpose To assess the feasibility of total shoulder denervation through two proposed incisions. Methods Total shoulder denervation was performed through an extended delta-pectoral approach and a transverse dorsal approach at the spine of the scapula. The study involved six cadavers. Course and number of articular branches from the lateral pectoral, axillary and supra-scapular nerve were documented. Results All shoulder joint articular branches were accessible through the proposed anterior and posterior approaches. The articular branch of the lateral pectoral nerve and supra scapular nerve were present in all the specimen. Axillary nerve articular branches were variable in number but when present anteriorly were proximal to the deltoid muscular branches and posteriorly proximal to the muscular branches to the teres minor. Conclusion Total glenohumeral denervation was feasible through our proposed anterior and posterior approaches. Enhanced knowledge of articular nerve branches could provide interventional targets for joint and ligament pain, with low risk of muscle weakness.

scholarly journals Motor learning and transfer: from feedback to feedforward control

2019 ◽  
Author(s):  
Rodrigo S. Maeda ◽  
Paul L. Gribble ◽  
J. Andrew Pruszynski
Keyword(s):  
Motor Learning ◽  
Muscle Activity ◽  
Shoulder Joint ◽  
Stretch Reflex ◽  
Feedforward Control ◽  
Motor Task ◽  
Joint Torques ◽  
Motor Commands ◽  
Shoulder Muscle ◽  
Long Latency

AbstractPrevious work has demonstrated that when learning a new motor task, the nervous system modifies feedforward (ie. voluntary) motor commands and that such learning transfers to fast feedback (ie. reflex) responses evoked by mechanical perturbations. Here we show the inverse, that learning new feedback responses transfers to feedforward motor commands. Sixty human participants (34 females) used a robotic exoskeleton and either 1) received short duration mechanical perturbations (20 ms) that created pure elbow rotation or 2) generated self-initiated pure elbow rotations. They did so with the shoulder joint free to rotate (normal arm dynamics) or locked (altered arm dynamics) by the robotic manipulandum. With the shoulder unlocked, the perturbation evoked clear shoulder muscle activity in the long-latency stretch reflex epoch (50-100ms post-perturbation), as required for countering the imposed joint torques, but little muscle activity thereafter in the so-called voluntary response. After locking the shoulder joint, which alters the required joint torques to counter pure elbow rotation, we found a reliable reduction in the long-latency stretch reflex over many trials. This reduction transferred to feedforward control as we observed 1) a reduction in shoulder muscle activity during self-initiated pure elbow rotation trials and 2) kinematic errors (ie. aftereffects) in the direction predicted when failing to compensate for normal arm dynamics, even though participants never practiced self-initiated movements with the shoulder locked. Taken together, our work shows that transfer between feedforward and feedback control is bidirectional, furthering the notion that these processes share common neural circuits that underlie motor learning and transfer.

scholarly journals Generalizing movement patterns following shoulder fixation

2020 ◽  
Vol 123 (3) ◽  
pp. 1193-1205 ◽  
Author(s):  
Rodrigo S. Maeda ◽  
Julia M. Zdybal ◽  
Paul L. Gribble ◽  
J. Andrew Pruszynski
Keyword(s):  
Muscle Activity ◽  
Shoulder Joint ◽  
Internal Model ◽  
Movement Patterns ◽  
Partial Reduction ◽  
Forearm Rotation ◽  
General Internal ◽  
Shoulder Muscle ◽  
Intersegmental Dynamics ◽  
Partial Learning

Generalizing newly learned movement patterns beyond the training context is challenging for most motor learning situations. Here we tested whether learning of a new physical property of the arm during self-initiated reaching generalizes to new arm configurations. Human participants performed a single-joint elbow reaching task and/or countered mechanical perturbations that created pure elbow motion with the shoulder joint free to rotate or locked by the manipulandum. With the shoulder free, we found activation of shoulder extensor muscles for pure elbow extension trials, appropriate for countering torques that arise at the shoulder due to forearm rotation. After locking the shoulder joint, we found a partial reduction in shoulder muscle activity, appropriate because locking the shoulder joint cancels the torques that arise at the shoulder due to forearm rotation. In our first three experiments, we tested whether and to what extent this partial reduction in shoulder muscle activity generalizes when reaching in different situations: 1) different initial shoulder orientation, 2) different initial elbow orientation, and 3) different reach distance/speed. We found generalization for the different shoulder orientation and reach distance/speed as measured by a reliable reduction in shoulder activity in these situations but no generalization for the different elbow orientation. In our fourth experiment, we found that generalization is also transferred to feedback control by applying mechanical perturbations and observing reflex responses in a distinct shoulder orientation. These results indicate that partial learning of new intersegmental dynamics is not sufficient for modifying a general internal model of arm dynamics. NEW & NOTEWORTHY Here we show that partially learning to reduce shoulder muscle activity following shoulder fixation generalizes to other movement conditions, but it does not generalize globally. These findings suggest that the partial learning of new intersegmental dynamics is not sufficient for modifying a general internal model of the arm’s dynamics.

scholarly journals Shared internal models for feedforward and feedback control of arm dynamics in non-human primates

2020 ◽  
Author(s):  
Rodrigo S. Maeda ◽  
Rhonda Kersten ◽  
J. Andrew Pruszynski
Keyword(s):  
Feedback Control ◽  
Muscle Activity ◽  
Shoulder Joint ◽  
Feedforward Control ◽  
Neural Mechanisms ◽  
Shoulder Muscle ◽  
Intersegmental Dynamics ◽  
Systematic Reduction ◽  
Elbow Motion ◽  
Feedback Responses

AbstractPrevious work has shown that humans account for and learn novel properties or the arm’s dynamics, and that such learning causes changes in both the predictive (i.e., feedforward) control of reaching and reflex (i.e., feedback) responses to mechanical perturbations. Here we show that similar observations hold in old-world monkeys (macaca fascicularis). Two monkeys were trained to use an exoskeleton to perform a single-joint elbow reaching and to respond to mechanical perturbations that created pure elbow motion. Both of these tasks engaged robust shoulder muscle activity as required to account for the torques that typically arise at the shoulder when the forearm rotates around the elbow joint (i.e., intersegmental dynamics). We altered these intersegmental arm dynamics by having the monkeys generate the same elbow movements with the shoulder joint either free to rotate, as normal, or fixed by the robotic manipulandum, which eliminates the shoulder torques caused by forearm rotation. After fixing the shoulder joint, we found a systematic reduction in shoulder muscle activity. In addition, after releasing the shoulder joint again, we found evidence of kinematic aftereffects (i.e., reach errors) in the direction predicted if failing to compensate for normal arm dynamics. We also tested whether such learning transfers to feedback responses evoked by mechanical perturbations and found a reduction in shoulder feedback responses, as appropriate for these altered arm intersegmental dynamics. Demonstrating this learning and transfer in non-human primates will allow the investigation of the neural mechanisms involved in feedforward and feedback control of the arm’s dynamics.

scholarly journals Explicit feedback and instruction do not change shoulder muscle activity reduction after shoulder fixation

2020 ◽  
Author(s):  
Rodrigo S. Maeda ◽  
Julia M. Zdybal ◽  
Paul L. Gribble ◽  
J. Andrew Pruszynski
Keyword(s):  
Muscle Activity ◽  
Shoulder Joint ◽  
The Third ◽  
Task Instructions ◽  
Visual Biofeedback ◽  
Shoulder Muscle ◽  
Intersegmental Dynamics ◽  
Elbow Movement ◽  
Human Participants ◽  
And Task

AbstractGenerating pure elbow rotation requires contracting muscles at both the shoulder and elbow joints to counter torques that arise at the shoulder when the forearm rotates (i.e., intersegmental dynamics). Previous work has shown that human participants learn to reduce their shoulder muscle activity if the same elbow movement is performed after the shoulder joint is mechanically locked, which is appropriate because locking the shoulder joint eliminates the torques that arise at the shoulder when the forearm rotates. However, this learning is slow (i.e., it unfolds over hundreds of trials) and incomplete (i.e., shoulder activity is not fully eliminated). Here we investigated whether and how the addition of explicit strategies and biofeedback modulate this type of learning. Three groups of human participants (N = 55) performed voluntary pure elbow rotations using a robotic exoskeleton that permits shoulder and elbow rotation in a horizontal plane. Participants did the task with the shoulder free to move (baseline), then with the shoulder joint locked by the robotic manipulandum (adaptation), and then with the shoulder free to move again (post-adaptation). The first group of participants performed this protocol and received no instructions about what to do after their shoulder was locked. The second group of participants received visual feedback about their shoulder muscle activity after each movement and was instructed to reduce their shoulder activity to zero. The third group of participants also received visual biofeedback, but it was removed part way through the experiment. We found that, although all groups learned, the rate and magnitude of learning was not reliably different across the groups. Taken together, our results suggest that learning new arm dynamics, unlike other motor learning paradigms, unfolds independent of explicit instructions, biofeedback and task instructions.

scholarly journals Results of treatment of arthrosis of the acromial-clavicular joint in patients with partial rupture of the supraspinatus muscle tendon

2021 ◽  
Author(s):  
Serhii S. Strafun ◽  
Serhii V. Bohdan ◽  
Samir M. Abbasov ◽  
Serhii O. Bezruchenko ◽  
Olexander S. Strafun
Keyword(s):  
Shoulder Joint ◽  
Supraspinatus Tendon ◽  
Abdominal Muscle ◽  
Clinical Group ◽  
Partial Rupture ◽  
Joint Function ◽  
Results Of Treatment ◽  
Post Surgery ◽  
Shoulder Muscle ◽  
Joint Material

Introduction: Very often, partial tear tendons of the superficial shoulder muscle are combined with arthrosis of the clavicular-acromial joint. This is due to violations of the shoulder-patch rhythm, which in turn leads to a chronic overload of the clavicular-acromial joint and the progression of arthrosis in this joint. Aim: The purpose of the study is to improve the results of treatment of patients with injuries of the supraspinatus tendon against the background of deforming arthrosis of the clavicular-acromial joint. Material and methods: For the study a clinical group was assembled, which consisted of 84 patients with injuries of the tendon of the supraspinatus and deforming arthrosis of the clavicular-acromial joint 3–4 parts. All patients, depending on the treatment, were divided into two groups. Results and discussion: The consequences and influence of the arthrosis of the clavicular-acromial joint were determined. Movements of the joint were examined. The shoulder joint function was under control in the post-surgery period, which provided particular results and conclusions according to the comparative analysis of the two groups. Conclusions: Based on the provided results, it can be concluded that deforming arthrosis of the clavicular acromial joint can cause contracture in the shoulder joint in patients after the suture of the tendon of the abdominal muscle.

Arthroscintigraphy in Suspected Rotator Cuff Rupture

1998 ◽  
Vol 37 (08) ◽  
pp. 272-278 ◽  
Author(s):  
S. Gratz ◽  
G. Köster ◽  
T. Behr ◽  
R. Vosshenrich ◽  
E. Grabbe ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Shoulder Joint ◽  
Clinical Signs ◽  
Diagnostic Efficiency ◽  
Rotator Cuff Rupture ◽  
Lower Viscosity ◽  
Rotator Cuff Lesion ◽  
Shoulder Region ◽  
Degenerative Alterations ◽  
Additional Value

Summary Aim: In order to evaluate the diagnostic efficiency of arthroscintigraphy in suspected rotator cuff ruptures this new imaging procedure was performed 20 times in 17 patients with clinical signs of a rotator cuff lesion. The scintigraphic results were compared with sonography (n = 20), contrast arthrography (n = 20) and arthroscopy (n = 10) of the shoulder joint. Methods: After performing a standard bone scintigraphy with intravenous application of 300 MBq 99m-Tc-methylene diphosphonate (MDP) for landmarking of the shoulder region arthroscintigraphy was performed after an intraarticular injection of 99m-Tc microcolloid (ALBURES 400 μCi/5 ml). The application was performed either in direct combination with contrast arthrography (n = 10) or ultrasound conducted mixed with a local anesthetic (n = 10). Findings at arthroscopical surgery (n = 10) were used as the gold standard. Results: In case of complete rotator cuff rupture (n = 5), arthroscintigraphy and radiographic arthrography were identical in 5/5. In one patient with advanced degenerative alterations of the shoulder joint radiographic arthrography incorrectly showed a complete rupture which was not seen by arthroscintigraphy and endoscopy. In 3 patients with incomplete rupture, 2/3 results were consistant. A difference was seen in one patient with a rotator cuff, that has been already revised in the past and that suffered of capsulitis and calcification. Conclusion: Arthroscintigraphy is a sensitive technique for detection of rotator cuff ruptures. Because of the lower viscosity of the active compound, small ruptures can be easily detected, offering additional value over radiographic arthrography and ultrasound, especially for evaluation of incomplete cuff ruptures.

Sign in / Sign up

Export Citation Format

Share Document