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Posterior Circumflex Humeral ArteryEdit

The Posterior Circumflex Humeral Artery (PCHA) is a key vessel of the shoulder region. It typically arises from the third part of the axillary artery and runs posteriorly around the surgical neck of the humerus, accompanying the axillary nerve through the quadrangular space to reach the posterior aspect of the shoulder. From there, it distributes branches to the glenohumeral joint and surrounding muscles, contributing to the joint’s collateral circulation and the perfusion of the deltoid and teres minor.

The PCHA is an important component of the shoulder’s vascular network, forming anastomoses with other arteries around the head of the humerus, notably the anterior circumflex humeral artery, to ensure robust blood supply to the region. Its course places it in proximity to the axillary nerve and the structures of the quadrangular space, making it clinically relevant in shoulder injuries and surgeries.

Anatomy

Origin and course

The Posterior Circumflex Humeral Artery most commonly arises from the third part of the axillary artery. After its origin, it courses posteriorly, entering the quadrangular space together with the axillary nerve. It winds around the posterior aspect of the surgical neck of the humerus, passing deep to the deltoid muscle and giving off branches that supply the shoulder joint and nearby musculature.

Branches

  • Articular branches to the glenohumeral joint and the shoulder capsule.
  • Muscular branches to nearby muscles, most notably the deltoid and the teres minor. The PCHA may also give small perforating branches that help perfuse surrounding soft tissues.

Relations and anastomoses

Within the shoulder region, the PCHA lies with the axillary nerve in the quadrangular space, an anatomical space bounded superiorly by the teres minor, inferiorly by the teres major, medially by the long head of the triceps brachii, and laterally by the surgical neck of the humerus. The artery forms a vital anastomotic network with the anterior circumflex humeral artery around the humeral head, and it communicates with other arteries supplying the shoulder such as the circumflex scapular artery and the suprascapular artery to ensure collateral circulation in cases of local obstruction.

Functional significance

The PCHA provides essential blood supply to the posterior aspect of the shoulder, including the glenohumeral joint and surrounding musculature. By contributing articular branches and muscular branches, it helps sustain synovial and muscular function of the shoulder, particularly during arm movement that emphasizes shoulder stability and rotator function.

Clinical significance

  • Fractures or dislocations around the shoulder, especially involving the surgical neck of the humerus, can threaten the PCHA. Injury to the artery can compromise perfusion of the shoulder joint and muscles supplied by the artery.
  • The artery is at risk during shoulder surgeries and arthroscopic procedures that require dissection near the quadrangular space. Preservation of the PCHA when feasible helps maintain joint viability and tissue perfusion.
  • Aneurysm or trauma of the PCHA is uncommon but can produce shoulder pain, vascular symptoms, or compressive effects on nearby nerves, most notably the axillary nerve.
  • Imaging modalities such as CT angiography, MR angiography, and Doppler ultrasound can visualize the PCHA and assess patency or injury in the setting of trauma or preoperative planning.

Variations

Anatomic variation is not unusual. In some people, the PCHA may originate from a common trunk with other vessels in the axillary region, or there can be duplicated branches. Rarely, atypical origins or anomalous courses may alter the relationship to the axillary nerve or to the quadrangular space, with potential implications for surgical approach and risk of iatrogenic injury.

Imaging and diagnosis

In trauma or preoperative assessment, imaging aims to delineate the PCHA’s size, course, and connections with the surrounding arterial network. CT angiography or MR angiography provides three-dimensional visualization of the axillary and shoulder vasculature, while Doppler ultrasonography can assess flow when a noninvasive, bedside evaluation is needed.

See also