Which statement correctly lists the external rotators of the shoulder?

Which statement correctly lists the external rotators of the shoulder?

• A. Infraspinatus and teres minor.
• B. Infraspinatus and teres minor, with posterior deltoid.
• C. Infraspinatus and teres minor, with assistance from posterior deltoid.
• D. Teres minor and posterior deltoid.

Answer: (C)

External rotation of the shoulder is dominated by two muscles of the rotator cuff: infraspinatus and teres minor. They attach to the humerus and drive the arm to turn outward. The posterior deltoid can help with this motion, but it isn’t a primary external rotator. Therefore, the statement that names the two main external rotators and notes that the posterior deltoid provides assistance best reflects how this movement works. The other options either omit one of the primary external rotators or imply the posterior deltoid is a primary external rotator.

External rotation of the shoulder is dominated by two muscles of the rotator cuff: infraspinatus and teres minor. They attach to the humerus and drive the arm to turn outward. The posterior deltoid can help with this motion, but it isn’t a primary external rotator. Therefore, the statement that names the two main external rotators and notes that the posterior deltoid provides assistance best reflects how this movement works. The other options either omit one of the primary external rotators or imply the posterior deltoid is a primary external rotator.