Rotator Cuff

The rotator cuff is a group of 4 muscles (supraspinatus, infraspinatus, subscapularis, and teres minor) that arise from the shoulder and wrap around the ball of the upper arm bone (humeral head) like a cuff. As a coat of muscles and tendons attached to the upper arm, it keeps the humeral head in the glenoid socket (socket formed by the shoulder blade) and assists in shoulder movement.