thoracoacromial

The thoracoacromial trunk, also known as the thoracoacromial artery, is a short arterial trunk that arises from the axillary artery. It typically comes from the second part of the axillary artery, near the lateral border of the pectoralis minor, and quickly divides into multiple branches that supply the chest wall, shoulder, and nearby structures.

Its four principal branches are the pectoral, clavicular, acromial, and deltoid arteries. The pectoral branch descends between the pectoralis major and pectoralis minor to supply these muscles and the overlying skin, contributing to the vascularization of the lower portion of the breast in females. The clavicular branch ascends to the region around the sternoclavicular joint and subclavius, often contributing to the vascular supply of adjacent tissues. The acromial branch runs toward the acromion and the deltoid area, supplying the acromial region and the anterior deltoid. The deltoid branch travels laterally with the deltoid muscle to nourish it and the overlying skin.

In addition to its target muscles, the trunk participates in anastomoses with branches of the lateral thoracic, thoracic intercostal, and circumflex networks, helping to supply the thoracic wall and shoulder girdle. Variations in the number and size of its branches are described in anatomical texts, but the four-branch pattern is the most commonly reported.