What is the role of the rotator cuff muscles?

The primary role of the rotator cuff muscles is to stabilize the shoulder joint. This group of four muscles—supraspinatus, infraspinatus, teres minor, and subscapularis—works together to maintain the stability of the glenohumeral joint, which is the main joint in the shoulder. They accomplish this by controlling the position of the humeral head within the shallow socket of the scapula during arm movements. This stability is crucial for both overhead motions and activities that require a wide range of shoulder mobility.

In contrast, the other answer choices focus on functions that are not related to the stabilizing role of the rotator cuff. Extending the elbow joint pertains to the muscles in the upper arm, elevating the scapula involves different muscles such as the trapezius and levator scapulae, and flexing the knee joint engages muscles in the thigh, unrelated to the shoulder mechanics.