Variant insertion of the teres major muscle

Abstract

The teres major (TerMa) muscle has a clinical significance for tendon transfer procedures in patients with massive rotator cuff tears. Individually, it originates from the dorsum of the inferior angle of scapula and inserts into the medial lip of bicepital groove of the humerus. Functionally, TerMa in cooperation with latissimus dorsi (LD) adducts arm, medially rotates arm, and assists in arm extension. The variation of TerMa insertion is very rare. In the shoulder and axillary regions of a 33-year-old Thai male cadaver, the variant insertion of the right TerMa was found. The muscle fibers of TerMa are directly attached at the supero-medial border of LD tendon. Notably, there was no terminal tendon of TerMa. To explain an unusual movement of the arm, this rare variation of the TerMa insertion is necessary to be recognized. This case report is very important for surgeons to preoperatively consider using the terminal tendon of TerMa for tendon transfer in treating patients with irreparable cuff tears.

Sports Injuries to the Latissimus Dorsi and Teres Major

“…40 Running deep and superior to the latissimus dorsi, the teres major originates from the posterior aspect of the inferior corner of the scapula and inserts just medial to the intertubercular groove and the latissimus dorsi insertion. 22 Surgical and cadaveric dissections have demonstrated that the latissimus dorsi and teres major tendons are often adherent to each other or that the teres major tendon may insert into the latissimus dorsi tendon. 4,32,39 Morelli et al 36 showed that in 15 of 18 shoulder specimens, the 2 tendons were confluent before separate humeral insertions.…”