Posterior Circumflex Humeral Artery, Posterior View

Description

Posteriorly, the posterior circumflex humeral artery curves around the surgical neck of the humerus after branching from the third part of the axillary artery, running with the axillary nerve through the quadrangular space. The boundaries are implied by teres minor superiorly, teres major inferiorly, the long head of triceps medially, and the humeral shaft laterally, with the vessel passing deep to the deltoid on the posterior aspect of the shoulder. Nearby landmarks include the scapular spine and acromion, the posterior glenohumeral region, and proximal humeral metaphysis. The vessel’s circumflex course stands out. This posterior perspective matters because the posterior circumflex humeral artery is the dominant arterial supply to the deltoid and contributes to anastomoses around the humeral head, so its position relative to the quadrangular space explains classic injury patterns. Posterior shoulder dislocation, proximal humerus fractures at the surgical neck, and iatrogenic injury during posterior approaches can compromise the artery and the axillary nerve together, producing deltoid weakness and sensory loss over the regimental badge area. It is a clean way to teach why intramuscular deltoid injections are placed in the mid-deltoid, away from deep neurovascular structures. Use this asset in upper limb anatomy lectures, surgical anatomy handouts for shoulder arthroscopy and open posterior approaches, and radiology teaching that correlates CT angiography with the axillary artery branches. It also fits textbook figures on the axillary region, the quadrangular space, and collateral circulation around the scapula and proximal humerus. Anatomical accuracy verified by SciePro's Medical Advisory Board.