Rotator Cuff Muscles

The rotator cuff muscles consist of the supraspinatus, infraspinatus, trees minor, and subscapularis, and insert on the humeral tuberosities.  A helpful mnemonic to recall these muscles is "SITS".  The rotator cuff muscles contribute to abduction (supraspinatus), rotate the humerus externally (infraspinatus, teres minor), and rotate the humerus internally (subscapularis).  The rotator cuff serves as a primary dynamic stabilizer of the shoulder.  It compresses the humeral head down in the glenoid fossa to counterbalance the elevating forces of the deltoid and other muscles acting on the humerus.  Weakness of the rotator cuff can predispose patients to impingement syndromes.