Pectoralis Major

Description

Prominently colored to isolate it from surrounding musculature, the pectoralis major is shown spanning the anterior thoracic wall in a male figure, with its clavicular head arising superiorly from the medial clavicle and its broader sternocostal fibers originating from the sternum and costal cartilages. From these medial attachments, fibers course laterally to converge toward the proximal humerus, where the tendon inserts on the lateral lip of the intertubercular sulcus (crest of the greater tubercle). A three-quarter anterior view clarifies how the muscle forms the anterior axillary fold as it passes inferolaterally, lying superficial to the pectoralis minor and adjacent superiorly to the deltoid across the deltopectoral interval. Fiber direction is the story. Clinically, this angle gives a practical sense of why tendon ruptures often present with loss of the anterior axillary fold and asymmetry during resisted adduction and internal rotation, a pattern commonly seen after heavy bench press or contact injury. The relationship to the deltopectoral groove also matters for surgical exposure, because the cephalic vein runs in this interval and the pectoralis major tendon becomes a key landmark during anterior approaches to the shoulder and proximal humerus. Seeing the clavicular and sternocostal portions together helps when teaching differential activation during flexion versus horizontal adduction, and when explaining referred pain patterns across the chest wall that can mimic cardiopulmonary symptoms. Anatomy faculty can drop this plate directly into upper-limb or thorax modules to support lectures on anterior shoulder landmarks, muscle architecture, and functional lines of pull. It also fits well in orthopedic and sports medicine content covering pectoralis major rupture repair, tendon avulsion, and postoperative rehabilitation planning where clear tendon-to-humerus orientation matters. Anatomical accuracy verified by SciePro's Medical Advisory Board.