Which rotator cuff muscle is responsible for internal rotation?

Which rotator cuff muscle is responsible for internal rotation?

• A. Supraspinatus
• B. Teres Minor
• C. Infraspinatus
• D. Subscapularis

Answer: (D)

Internal rotation of the humerus is carried out primarily by the subscapularis, a rotator cuff muscle located on the anterior surface of the scapula and attaching to the lesser tubercle of the humerus. When it contracts, it pulls the humeral head medially and rotates the arm inward, while also helping to stabilize the glenohumeral joint. In contrast, the supraspinatus initiates arm abduction, and the infraspinatus and teres minor rotate the arm externally. So, among the rotator cuff muscles, subscapularis is the one that performs internal rotation.

Internal rotation of the humerus is carried out primarily by the subscapularis, a rotator cuff muscle located on the anterior surface of the scapula and attaching to the lesser tubercle of the humerus. When it contracts, it pulls the humeral head medially and rotates the arm inward, while also helping to stabilize the glenohumeral joint. In contrast, the supraspinatus initiates arm abduction, and the infraspinatus and teres minor rotate the arm externally. So, among the rotator cuff muscles, subscapularis is the one that performs internal rotation.