Which of the following statements about the Rotator cuff muscles is incorrect?

The statement regarding the supraspinatus muscle claiming it adducts the arm is incorrect. In fact, the primary function of the supraspinatus is to initiate arm abduction, particularly in the first 15 degrees of arm movement. Once the arm is abducted beyond this initial phase, other muscles, primarily the deltoid, take over the responsibility for continuing the movement.

The values and functions of the other rotator cuff muscles are accurately stated. The infraspinatus and teres minor are well-known for their roles in externally rotating the arm, contributing to the stability and controlled movement of the shoulder joint. Meanwhile, the subscapularis is correctly noted for its role in internal rotation, completing the functional quartet of the rotator cuff that stabilizes and allows for a wide range of shoulder movements. Understanding these roles is crucial for recognizing how injuries and conditions affecting the rotator cuff may limit shoulder function.