A rotator cuff muscle of the shoulder, which is partially covered by the deltoid and trapezius muscles. The infraspinatus has its origin on the underside of the shoulder blade, on the infraspinous fossa, and its insertion on the greater tubercle of the humerus. Its primary actions about the shoulder are lateral rotation and horizontal abduction. It also helps to hold the head of the humerus in the glenoid cavity.
Subjects: Sports and Exercise Medicine.