Supraspinatus Fossa

The capsule of the glenohumeral joint is loose and pleated. The ligaments, which are merely thickenings in the capsule, provide little support. The major support of the humerus into the fossa is provided by the rotator cuff muscles, which hold the head into the fossa. These muscles include the supraspinatus, infraspinatus, teres minor, and subscapularis. Abduction-adduction and axial and horizontal rotations are coupled in that angular motions are accompanied by translatory slides. The caudal slide of the humeral head with abduction confers increased freedom of motion on the supraspinatus tendon beneath the coracoacromial ligament. 

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