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.
Adult ; Arm ; Asian Continental Ancestry Group ; Cadaver ; Humans ; Humerus ; Lip ; Male ; Muscles ; Rotator Cuff ; Scapula ; Shoulder ; Tendon Transfer ; Tendons

Many origins and insertions of an axillary muscular slip (also known as Langer's or axillary arch muscles) have been documented previously. In this report, we found duplicated axillary arch muscles (two variant muscular slips) originating from the inferolateral border of the right side latissimus dorsi muscle. Obviously, these axillary arch muscles can be distinguished as short and long muscular strips. While the origin was the same, the short muscular slip inserts into the fascia covering on the pectoralis minor, whereas the longer one inserts on/into the aponeurosis of pectoralis major. For the surgery in the axillary region, this rare variation should be considered a cause of surgical interventions.
Fascia ; Muscles