Which muscle inserts into the intertubercular groove of the humerus?

Which muscle inserts into the intertubercular groove of the humerus?

• A. Biceps Brachii
• B. Subscapularis
• C. Teres Major
• D. Palmaris Longus

Answer: (C)

Understanding where muscles attach to the proximal humerus helps explain why this muscle is the correct choice. The intertubercular groove sits between the greater and lesser tubercles, and the tendon/insertions that reach this area determine which muscle is attached there. Teres major attaches to the medial lip of the intertubercular groove, so its insertion sits right along that groove. That placement explains its actions—extending, adducting, and medially rotating the arm—and aligns with its origin from the inferior angle of the scapula. In contrast, the biceps brachii inserts at the radial tuberosity (and a nearby fascia), subscapularis inserts on the lesser tubercle, and palmaris longus is a forearm muscle inserting into the palmar aponeurosis. Latissimus dorsi also uses the intertubercular groove, but its insertion is on the floor of the groove, not the medial lip, and it isn’t listed among the given choices.

Understanding where muscles attach to the proximal humerus helps explain why this muscle is the correct choice. The intertubercular groove sits between the greater and lesser tubercles, and the tendon/insertions that reach this area determine which muscle is attached there. Teres major attaches to the medial lip of the intertubercular groove, so its insertion sits right along that groove. That placement explains its actions—extending, adducting, and medially rotating the arm—and aligns with its origin from the inferior angle of the scapula.

In contrast, the biceps brachii inserts at the radial tuberosity (and a nearby fascia), subscapularis inserts on the lesser tubercle, and palmaris longus is a forearm muscle inserting into the palmar aponeurosis. Latissimus dorsi also uses the intertubercular groove, but its insertion is on the floor of the groove, not the medial lip, and it isn’t listed among the given choices.