Subscapularis Rotator Cuff Tear

The rotator cuff is a series of four muscles that run along the shoulder blade (scapula) around the shoulder socket (glenoid) and attach to the ball of the shoulder (humeral head) by their tendons. The muscles of the rotator cuff work to keep the humeral head centered in the socket as the arm moves. The subscapularis muscle, in particular, runs along the underside of the scapula (shoulder blade) and attaches to the anterior (front) portion of the humeral head. This muscle is critical for internal rotation of the humerus and stability of the shoulder joint. Injury or degeneration (wear and tear) can result in a tear of the subscapularis tendon. Not only do rotator cuff tears cause weakness and pain, but the resulting dysfunction results in an inability to keep the humeral head centered on the socket, which results in additional irritation and pain of the shoulder.