Where does the latissimus dorsi insert?

• A. Crest of lesser tubercle of the humerus
• B. Intertubercular groove
• C. Greater tubercle
• D. Deltoid tuberosity

Answer: (A)

The latissimus dorsi attaches to the floor of the intertubercular (bicipital) groove of the humerus. This placement lets the muscle pull the humerus upward and backward, producing extension, adduction, and medial rotation of the arm. The groove is a shared site where several muscles connect near the tubercles: the lateral lip is typically for pectoralis major, the medial lip for teres major, and the floor for latissimus dorsi. Other options point to different structures: the crest near the lesser tubercle corresponds to subscapularis, the greater tubercle is the insertion for the rotator cuff muscles, and the deltoid tuberosity is where the deltoid inserts.