Pectoralis Major

Description

Anterior soft tissues are removed to expose the female anterior thorax, with the pectoralis major forming the dominant superficial muscle of the chest wall from the medial clavicle and sternum toward its lateral humeral insertion. Its clavicular and sternocostal parts converge laterally into a broad tendon that twists before attaching along the lateral lip of the intertubercular sulcus of the humerus, just medial to the deltoid and the deltopectoral groove. Superficial fascia overlying the muscle transitions into the breast, where the mammary gland sits anterior to the pectoral fascia across the retromammary plane, emphasizing the layered relationship between glandular tissue, fascia, and muscle. Neck and facial musculature remain visible superiorly, anchoring the figure in full anterior anatomical context. Clear planes. Surgical anatomy of the pectoralis major in a woman often hinges on these fascial interfaces: the pectoral fascia and the loose areolar retromammary space define the dissection plane used in mastectomy and in raising skin flaps, while the muscle itself is the boundary for subpectoral implant placement and a common source for myocutaneous flaps. Lateral fibers of pectoralis major also frame the anterior axillary fold, a practical surface landmark when planning axillary access and orienting incisions for breast surgery. At the humeral tendon, acute rupture can occur with eccentric loading during bench press, typically producing loss of the anterior axillary fold and weakness in adduction and internal rotation. Ideal for teaching pectoralis major fiber direction, tendon orientation, and breast-to-chest wall relationships in gross anatomy, surgical anatomy, and plastic and reconstructive surgery modules, and for illustrating operative planes in breast oncology texts, implant-based reconstruction guides, and patient-facing educational materials where accurate female anatomy matters. Anatomical accuracy verified by SciePro's Medical Advisory Board.