Posterior Perspective of the Teres Major Under the Skin

Description

Posterior skin-on anatomy of the male shoulder girdle places the teres major along the inferolateral border of the scapula, arising from the dorsal surface of the inferior angle and adjacent lateral border and running superolaterally toward the proximal humerus. Immediately superior to it sits the teres minor on the posterior scapula, and together they frame the quadrangular space laterally while the long head of triceps brachii would lie medially, descending from the infraglenoid tubercle. The muscle belly of teres major tucks just inferior to the posterior axillary fold, with its tendon coursing anterior to the long head of triceps to insert on the medial lip of the intertubercular sulcus (crest of the lesser tubercle) of the humerus. This relationship is easiest to appreciate from the back. Clinically, separating teres major from teres minor matters because only teres minor belongs to the rotator cuff and contributes to glenohumeral external rotation, whereas teres major acts with latissimus dorsi to adduct, extend, and medially rotate the arm at the shoulder. That distinction comes up in shoulder examinations, where isolated weakness of external rotation suggests posterior cuff pathology while preserved power with resisted adduction and extension argues against primary teres major injury. It also guides surgical planning for tendon transfers in brachial plexus palsy or massive rotator cuff tears, where latissimus dorsi and teres major may be mobilized near the posterior axillary fold and along the medial humerus. Use this posterior perspective for gross anatomy teaching on scapulohumeral muscles, for orthopedic and sports medicine texts discussing posterior shoulder pain and differential diagnosis of rotator cuff dysfunction, and for surgical atlases illustrating landmarks around the quadrangular space and posterior axillary fold. Anatomical accuracy verified by SciePro's Medical Advisory Board.