title: 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.
authors.affiliation: Department of Anatomy, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. ; Integrative Complementary Alternative Medicine (ICAM) Research and Development Group, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Sitthichai
authors.initials: S
authors.lastname: Iamsaard
authors.forename: Nut
authors.initials: N
authors.lastname: Thunyaharn
authors.forename: Kowit
authors.initials: K
authors.lastname: Chaisiwamongkol
authors.forename: Porntip
authors.initials: P
authors.lastname: Boonruangsri
authors.forename: Nongnut
authors.initials: N
authors.lastname: Uabundit
authors.forename: Wiphawi
authors.initials: W
authors.lastname: Hipkaeo
keywords: Latissimus dorsi; Rotator cuff tears; Tendon transfer; Teres major muscle; Variant insertion