Which of the following is NOT a rotator cuff muscle?

• A. Scalenes
• B. Supraspinatus
• C. Infraspinatus
• D. Subscapularis

Answer: (A)

Rotator cuff muscles stabilize the shoulder by keeping the head of the humerus centered in the glenoid and guiding rotation. The four muscles that make up this cuff are supraspinatus, infraspinatus, teres minor, and subscapularis. Scalenes are neck muscles that assist with neck movement and respiration, not with stabilizing the shoulder joint. Therefore, the muscle that is not part of the rotator cuff is the scalene. The other listed muscles are rotator cuff muscles.