Examination of the Pectoralis Muscle

Description

Centered on the anterior thorax of an adult female, the pectoralis major is rendered as a broad, fan-shaped muscle arising from the medial clavicle, sternum, and costal cartilages, its fibers converging laterally into a flattened tendon inserting on the lateral lip of the intertubercular sulcus of the humerus. Superiorly and laterally, its border forms the anterior axillary fold as it approaches the proximal arm, with the deltoid occupying the shoulder cap just lateral to the clavicular head. Overlying the muscle, the breasts are represented with superficial adipose tissue and glandular contour, allowing the viewer to appreciate how mammary tissue sits anterior to the pectoral fascia rather than within the muscle itself. Regional bony landmarks such as the clavicles, ribs, and portions of the upper limb skeleton provide orientation. Breast and chest wall procedures depend on this relationship. Subpectoral breast implant placement and expander reconstruction exploit the plane deep to pectoralis major, while mastectomy and lumpectomy require clear separation of breast tissue from the pectoral fascia to reduce residual disease on the chest wall. Nerve supply matters here: the lateral and medial pectoral nerves enter the deep surface near the clavicopectoral fascia, and iatrogenic injury can weaken adduction and internal rotation. A common teaching point. The depiction also helps explain why pectoralis major tears often present at the humeral tendon after eccentric loading, classically during bench press. Ideal for gross anatomy and surface anatomy teaching in medical or physiotherapy curricula, this artwork also supports plastic surgery and breast oncology publications that need an accurate anterior map of breast position relative to pectoralis major and its tendon. It fits patient-facing surgical counseling materials when you need clear planes without distracting dissection detail. Anatomical accuracy verified by SciePro's Medical Advisory Board.