An artery that branches from the axilliary artery and supplies the deltoid, teres major, teres minor, and long and lateral heads of the triceps brachii muscles, glenohumeral joint, and the cutaneous supply to the area posterolateral to the proximal humerus. This artery courses posteriorly with the axillary nerve, through the quadrangular space, to the posterior aspect of the humerus and anastomoses with the anterior humeral circumflex artery. [ https://www.elsevier.com/resources/anatomy/cardiovascular-system/arteries/posterior-circumflex-humeral-artery/24676 ]