Thoracoacromial artery

Course

The thoracoacromial artery arises near the axilla at the level of the suprascapular notch from the second part of the axillary artery.

It courses downwards, deep to the medial border of the pectoralis minor muscle, after which it pierces the clavipectoral fascia. Recall that the clavipectoral fascia represents the deep layer of the pectoral fascia that bridges the space between the clavicle and pectoralis minor muscle. Here, the thoracoacromial artery divides into its terminal branches.

Branches and supply

The thoracoacromial artery gives off four branches to supply the muscles and skin of the pectoral region; the pectoral, deltoid, clavicular and acromial branches.

• Pectoral branch: courses downward between the pectoralis major and minor muscles. After giving off a branch to supply the pectoralis minor, it pierces the posterior surface of the pectoralis major and emerges onto its anterior surface. Here, it anastomoses with the intercostal branches of the internal thoracic and lateral thoracic arteries. Aside from the branch to pectoralis minor, it also gives off perforating branches to supply the breast, and musculocutaneous perforating branches to supply the skin over pectoralis major.
• Acromial branch: courses over the coracoid process of scapula and pierces and supplies the deltoid muscle, emerging at the superior surface of the acromion. Here, it anastomoses with branches of the suprascapular artery, the deltoid branch of the thoracoacromial artery and the posterior circumflex humeral arteries. 
• Clavicular branch: courses superomedially between the clavicular part of pectoralis major and the clavipectoral fascia. Along its course, it supplies the sternoclavicular joint and subclavius muscle.
• Deltoid branch: courses over the pectoralis minor muscle, being accompanied by the cephalic vein. It runs between the pectoralis major and deltoid muscles, supplying them along the way. The deltoid branch may occasionally arise from the acromial branch of the thoracoacromial artery.