The pectoralis major tendon is a bilaminar flat tendon inserting on the lateral lip of the intertubercular groove of the humerus. The anterior lamina (from the clavicular head) inserts proximally, while the posterior lamina (from the sternocostal head) inserts distally and rotates so that the inferior fibres from the sternocostal head end up most proximal at the insertion. The tendon is approximately 4-5 cm wide at its insertion and can be palpated along the anterior axillary fold.
Pectoralis major tendon tears occur primarily in young male weightlifters and contact sport athletes during bench press and resisted shoulder internal rotation. The tear typically occurs at the humeral insertion rather than the muscle-tendon junction. A palpable gap in the anterior axillary fold, asymmetric chest wall contour, and weakness of horizontal adduction and internal rotation are the clinical findings. MRI confirms the tear pattern and surgical repair is recommended for complete tears in active patients, using direct suture anchor fixation to the humeral footprint.
Violent eccentric contraction during bench press or wrestling avulses the pectoralis major tendon from its humeral insertion, producing a palpable defect at the anterior axillary fold, anterior axillary ecchymosis, and marked weakness of horizontal adduction, managed by surgical reattachment to the lateral bicipital groove with suture anchors in active patients.
