Which set of anatomic structures comprises the rotator cuff?

Which set of anatomic structures comprises the rotator cuff?

• A. Deltoid, Latissimus dorsi, Pectoralis major, Teres major
• B. Biceps, Triceps, Brachialis, Coracobrachialis
• C. Supraspinatus, Infraspinatus, Teres minor, Subscapularis
• D. Supraspinatus only

Answer: (C)

The rotator cuff is formed by four muscles whose tendons blend with the shoulder joint capsule to hold the head of the humerus in the glenoid as the arm moves. These four muscles are responsible for both stabilizing the joint and producing key shoulder motions. Supraspinatus starts the first portion of arm lifting (abduction) from the side, while infraspinatus and teres minor mainly control external rotation, and subscapularis provides internal rotation and some adduction. This combination is what keeps the humeral head centered during movement and protects the joint from dislocation or impingement. The other options include muscles that are not part of the rotator cuff—larger shoulder girdle muscles or arm muscles that move the arm in other ways—so they don’t form the cuff around the humeral head. The rotator cuff, specifically, is the four-muscle set just described.

The rotator cuff is formed by four muscles whose tendons blend with the shoulder joint capsule to hold the head of the humerus in the glenoid as the arm moves. These four muscles are responsible for both stabilizing the joint and producing key shoulder motions. Supraspinatus starts the first portion of arm lifting (abduction) from the side, while infraspinatus and teres minor mainly control external rotation, and subscapularis provides internal rotation and some adduction. This combination is what keeps the humeral head centered during movement and protects the joint from dislocation or impingement.

The other options include muscles that are not part of the rotator cuff—larger shoulder girdle muscles or arm muscles that move the arm in other ways—so they don’t form the cuff around the humeral head. The rotator cuff, specifically, is the four-muscle set just described.