Where does the teres major insert?

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

Answer: (A)

The teres major attaches to the medial lip of the intertubercular groove (bicipital groove) of the humerus. This groove, located between the greater and lesser tubercles, hosts several nearby insertions: teres major and latissimus dorsi insert on the medial lip, while pectoralis major inserts on the lateral lip, and the rotator cuff muscles attach to the greater tubercle. The crest of the lesser tubercle is where subscapularis inserts, the greater tubercle is the site for supraspinatus, infraspinatus, and teres minor, and the deltoid tuberosity is where deltoid inserts. So the intertubercular groove is the correct insertion site for teres major.

(Functional note: teres major helps medially rotate, adduct, and extend the arm, aided by its nerve supply from the lower subscapular nerve.)