Pectoralis Major

Description

Oblique lateral anatomy of the male thorax highlights the pectoralis major draped over the anterior chest wall, with the long, parallel fibers of the sternal head running from the sternum and costal cartilages toward a narrow tendon at the proximal humerus. Superiorly, the clavicular head can be inferred near the medial clavicle, blending laterally with the sternal fibers as the muscle converges toward the shoulder joint. Deep and posterior landmarks remain legible through the transparency, including the rib cage curving posteriorly to the thoracic vertebrae, the scapula on the posterolateral thorax, and the clavicle spanning anteriorly to the acromial region. The pectoralis major belly lies anterior to the ribs and costal cartilages, while its insertion sits lateral to the bicipital groove at the lateral lip of the intertubercular sulcus (crest of the greater tubercle). Orientation matters here because the lateral view clarifies how pectoralis major tension crosses the glenohumeral joint to drive adduction and internal rotation, and how the inferior sternal fibers contribute to extension from a flexed position. That fiber direction is the key teaching point for tendon rupture patterns in weightlifters during the eccentric phase of a bench press, where the humeral insertion often fails and the anterior axillary fold contour is lost. Surgeons planning deltopectoral exposure or pectoralis major tendon repair also rely on these relationships to the clavicle, humerus, and anterior axillary fold. Use this artwork in gross anatomy labs when correlating surface anatomy of the anterior chest with deep attachments, and in orthopedics or sports medicine materials covering pectoralis major strains and ruptures. It also fits well in atlases or patient education explaining shoulder mechanics and anterior chest wall musculature. Anatomical accuracy verified by SciePro's Medical Advisory Board.