Which muscles constitute the rotator cuff?

The rotator cuff comprises four specific muscles: the supraspinatus, infraspinatus, teres minor, and subscapularis. These muscles play a crucial role in stabilizing the glenohumeral joint (shoulder joint) and facilitating shoulder movements.

The supraspinatus is responsible for initiating arm abduction, while the infraspinatus and teres minor assist in external rotation of the shoulder. The subscapularis is the primary muscle involved in internal rotation. Together, these muscles form a supportive cuff around the shoulder, helping to keep the head of the humerus securely within the shallow glenoid cavity of the scapula during various arm movements. This is essential for maintaining joint stability during activities that involve lifting and throwing.

The other choices list muscles that do not belong to the rotator cuff group, highlighting their functions and locations in different areas of the body. The deltoid, for example, is a major muscle of the shoulder that primarily acts to lift the arm, while the muscles in the third and fourth options are associated with the trunk and do not play a role in shoulder stabilization or movement.