Which action is primarily performed by the teres minor?

The teres minor primarily functions in shoulder lateral rotation and stabilization of the humeral head. This muscle, located in the rotator cuff, plays a critical role in the mechanics of the shoulder joint. Specifically, when the teres minor contracts, it causes the humerus to rotate laterally, which is essential for various movements of the arm, especially those that involve lifting or reaching overhead.

In addition to its role in lateral rotation, the teres minor also contributes to the stabilization of the humeral head within the shallow glenoid cavity of the scapula. This stabilization is crucial for maintaining shoulder function and preventing dislocation, especially during arm movements that involve force or complexity.

While other muscles may contribute to shoulder abduction, medial rotation, or flexion, the teres minor's unique actions focus specifically on lateral rotation and stabilization, making this option the most accurate representation of its primary function.