The infraspinatus muscle is one of the rotator cuff muscles. The stability of the shoulder joint is mainly provided by the tendons of the subscapularis, teres minor, infraspinatous, and supraspinatous muscles that together form the rotator cuff. The cuff is fused to the underlying joint capsule except inferiorly. Because of the lack of inferior stability, most dislocations or subluxations occur in this direction. The shoulder is most vulnerable when fully abducted and a force from a superior origin is applied.