Which muscle inserts at the intertubercular groove of the humerus?

• A. Teres Major
• B. Supraspinatus
• C. Subscapularis
• D. Brachioradialis

Answer: (A)

Understanding where a muscle inserts on the humerus helps you predict its action. The intertubercular groove (the bicipital groove) on the humerus serves as a landmark for several tendon attachments: the medial lip is where teres major attaches, the lateral lip is where pectoralis major attaches, and the floor is where latissimus dorsi inserts. Among the given options, the muscle that specifically inserts at the intertubercular groove is teres major, attaching at the medial lip. This placement aligns its pull to adduct and medially rotate the arm, especially when the arm is in extension. The other muscles have different insertion sites—supraspinatus attaches to the greater tubercle, subscapularis to the lesser tubercle, and brachioradialis inserts onto the distal radius—so they don’t insert at the intertubercular groove.