Pectoralis Major at the Humerus

tendo musculi pectoralis majoris ad humerum

The pectoralis major inserts via a broad bilaminar tendon on the lateral lip of the bicipital groove of the humerus. The two layers (clavicular head — anterior layer; sternocostal head — posterior layer) twist on themselves as they converge on the humerus so that the sternocostal head (from lower ribs) inserts most superiorly on the humerus and the clavicular head inserts inferiorly. The footprint spans approximately 5 cm on the lateral bicipital groove anterior lip.

Region: Shoulder

Clinical Relevance

Clinical Notes

Pectoralis major tears are most common in weightlifters performing bench press, occurring at the musculotendinous junction (most common) or less commonly at the humeral tendon insertion. Complete tears produce ecchymosis extending from the axilla to the chest, loss of the anterior axillary fold contour, and weakness of adduction and internal rotation. MRI confirms tear location and extent. Surgical repair of complete tears within 3 months produces significantly better outcomes than late repair; the bilaminar tendon must be reduced to its humeral footprint with suture anchors.

Pathology

Common Injuries & Conditions

Pectoralis Major Tendon Avulsion in Bench Press

Maximum eccentric loading during bench press eccentrically overloads the pectoralis major at the musculotendinous junction or at the humeral footprint, producing sudden anterior shoulder pain with ecchymosis and visible deformity of the anterior axillary fold; MRI distinguishes partial from complete tears and early surgical repair within 8 weeks produces the best functional outcomes.