The Hip - book
Home » Muscles Tendons » Muscular Stabilizers of the Shoulder

Muscular Stabilizers of the Shoulder

- Discussion:
    - shoulder is bounded posteriorly by teres minor & infraspinatus & partialy by long head of triceps;
    - it is bounded laterally by deltoid, & superiorly it is bounded by acromion;
    - anteriorly & inferiorly, shoulder is bounded by pect major & biceps, however, these do not completely stabilize glenohumeral joint;
           - anteriorly, articular ligaments & joint capsule provide major support;

- Subscapularis:
    - acts as secondary restraint & is frequently attenuated w/ shoulder dislocations;

- Supraspinatus, Intraspinatus, & Teres minor:
    - originates from posterior aspect of scapula & inserts into greater tuberosity;
    - these muscles resist anterior translation of the proximal humerus;
    - these muscles are necessarily stretched to allow anterior dislocation & in a minority of dislocations, there may be an avulsion of their insertion during dislocation to stabilize the shoulder

Dynamic capsuloligamentous anatomy of the glenohumeral joint.

Dynamic stability of the glenohumeral joint.  

Stabilizing mechanisms preventing anterior dislocation of the glenohumeral joint