Teres Major, Posterior View

Description

Arising from the posterior surface of the inferior angle and adjacent lateral border of the scapula, the teres major courses superolaterally toward the proximal humerus, forming a thick muscular band along the posterior axillary fold. Its tendon inserts on the medial lip of the intertubercular sulcus (crest of the lesser tubercle), just medial to the tendon of latissimus dorsi, with the glenohumeral joint and humeral head situated anterolateral to its line of pull. Surrounding bony landmarks include the scapular spine and acromion superiorly, the ribs and thoracic spinous processes medially, and the humeral shaft descending distally. Red muscle overlays also cue the neighboring teres minor superiorly and the posterior scapular musculature that frames the posterior shoulder. Posterior orientation matters because teres major is easiest to teach and to surgically localize by following the inferior scapular angle into the posterior axillary fold, where it lies inferior to teres minor and superior to latissimus dorsi. In shoulder biomechanics, this muscle is a primary adductor and internal rotator of the humerus, and it often tightens with overhead athletes, contributing to posterior shoulder stiffness and altered humeral head translation during abduction. The relationship to the quadrangular and triangular spaces is also legible from behind, helping learners distinguish where the axillary nerve and posterior circumflex humeral artery travel relative to teres minor, teres major, and the long head of triceps. Common use cases include gross anatomy lab materials on the posterior shoulder and axilla, rehabilitation texts discussing internal rotation and adduction strength testing, and surgical or sports medicine publications describing posterior shoulder approaches and muscle-tendon transfers that reference the teres major insertion near the bicipital groove. It also supports radiology teaching when correlating posterior scapular landmarks with MRI slices through the rotator cuff interval and posterior axillary fold. Anatomical accuracy verified by SciePro's Medical Advisory Board.