Which muscle inserts at the lesser tubercle of the humerus?

Which muscle inserts at the lesser tubercle of the humerus?

• A. Subscapularis
• B. Supraspinatus
• C. Teres Major
• D. Biceps Brachii

Answer: (A)

Where a muscle attaches to the humerus helps identify it. The lesser tubercle on the anterior proximal humerus is the insertion site for the subscapularis. This muscle is one of the rotator cuff muscles that sits on the front of the shoulder and it originates from the subscapular fossa, then inserts on the lesser tubercle to medially rotate the arm and stabilize the humeral head in the socket. The other muscles listed attach elsewhere: supraspinatus inserts on the greater tubercle and assists with initiating abduction; teres major attaches to the medial lip of the intertubercular groove and helps with adduction and medial rotation; the biceps brachii inserts on the radial tuberosity and does not attach to the humeral tubercles. So the lesser tubercle is uniquely the insertion point for subscapularis, making it the correct choice.

Where a muscle attaches to the humerus helps identify it. The lesser tubercle on the anterior proximal humerus is the insertion site for the subscapularis. This muscle is one of the rotator cuff muscles that sits on the front of the shoulder and it originates from the subscapular fossa, then inserts on the lesser tubercle to medially rotate the arm and stabilize the humeral head in the socket. The other muscles listed attach elsewhere: supraspinatus inserts on the greater tubercle and assists with initiating abduction; teres major attaches to the medial lip of the intertubercular groove and helps with adduction and medial rotation; the biceps brachii inserts on the radial tuberosity and does not attach to the humeral tubercles. So the lesser tubercle is uniquely the insertion point for subscapularis, making it the correct choice.