Large pectoralis muscle

The large pectoral muscle (m. Pectoralis major) is massive, fan-shaped, occupying a considerable part of the anterior wall of the thoracic cavity. Accordingly, the place of its origin in the muscles distinguish the clavicular part (pars clavicularis), which begins on the medial half of the clavicle; the sternocostalis (pars sternocostalis) - it originates on the front surface of the sternum and the cartilages of the upper six ribs, and the abdominal part (pars abdominalis), which begins on the anterior wall of the vagina of the rectus abdominis. The bundles of the large pectoral muscle, noticeably converging, extend laterally and are attached to the crest of the large tubercle of the humerus. The large pectoral muscle is separated from the deltoid muscle by a well-defined deltoid-thoracic sulcus (sulcus deltoideopectoralis - BNA), which upward and medially passes into the subclavian fossa. Being superficially, the large pectoral muscle, together with the small pectoral muscle, forms the anterior wall of the axillary cavity.

Function: the raised arm lowers and leads to a trunk, simultaneously turning it inside. If the arm is strengthened in a raised position, it raises the ribs and sternum, contributing to the expansion of the chest (an auxiliary respiratory muscle).

Innervation: medial and lateral thoracic nerves (СVII-ThI).

Blood supply: pectoral and posterior intercostal arteries, anterior intercostal branches of the internal thoracic artery.

[1], [2], [3]