Posterior Circumflex Humeral Artery

Origin

The posterior circumflex humeral artery arises from the third part of the axillary artery, at the level of the inferior edge of the subscapularis muscle. It is larger than its anterior counterpart.

The origin of the posterior circumflex humeral artery is somewhat variable. In about 20% of individuals, the posterior circumflex humeral and the subscapular arteries originate from a common trunk. Additionally, in about 20% of individuals, the anterior and posterior circumflex humeral arteries originate from a common trunk (Tubbs, Shoja and Loukas, 2016).

Course

The posterior circumflex humeral artery courses posteriorly with the axillary nerve. It traverses the quadrangular space in 85% of individuals.

The quadrangular space is bordered by teres minor muscle superiorly, teres major muscle inferiorly, long head of the triceps brachii muscle medially, and the surgical neck of the humerus laterally. The posterior circumflex humeral artery winds around the surgical neck of the humerus and unites with the anterior circumflex humeral artery.

Branches

A descending branch arises from the posterior circumflex humeral artery and unites with the deltoid branch of the deep brachial artery. It anastomoses with the anterior circumflex humeral artery to complete a humeral ring. It also anastomoses with the acromial branch of the suprascapular artery and the thoracoacromial branches.

Supplied Structures

The posterior circumflex humeral artery contributes to the supply of the deltoid, teres major, teres minor, and the long and lateral heads of the triceps brachii muscles. It also supplies the glenohumeral joint and the cutaneous tissue overlying the posterolateral aspect of the proximal humerus.

References

Tubbs, R. S., Shoja, M. M. and Loukas, M. (2016) Bergman's Comprehensive Encyclopedia of Human Anatomic Variation. Wiley.