Comprehensive Osteopathic Medical Licensing Examination (COMLEX USA) Practice

What action does the teres minor primarily perform?

1. Abduction

2. Flexion

3. External rotation

4. Internal rotation

The correct answer is: External rotation

The teres minor is primarily responsible for external rotation of the arm. As a small muscle located in the rotator cuff, it plays a critical role in stabilizing the shoulder joint while allowing for the arm to rotate outward. This action is essential for many movements that involve lifting the arm away from the body or performing various overhead activities. Understanding the role of the teres minor in the context of shoulder function is important for comprehending its contribution to both normal biomechanics and potential shoulder injuries. Other muscles in the rotator cuff, such as the infraspinatus, also assist in external rotation, but the teres minor contributes significantly to this functionality. This distinguishes it from other actions listed, like abduction, flexion, or internal rotation, which are primarily carried out by different muscles in the shoulder girdle.