Variant Course of Posterior Circumflex Humeral Artery Associated with the Abnormal Origin of Radial Collateral Artery: Could It Mimic the Quadrangular Space Syndrome?

Variations in the origin of axillary artery branches are common. But, distinctly abnormal course of its posterior circumflex humeral branch is rare. We are reporting a case of posterior circumflex humeral artery (PCHA) originating from the axillary artery, passing through lower triangular space to reach the scapular region where it accompanied the axillary nerve and posterior circumflex humeral vein to pass around surgical neck of humerus, deep to the fibers of deltoid. Other variations observed in this specimen were the radial collateral artery arising from the PCHA, middle collateral artery arising directly from the brachial artery and absence of profunda brachii artery. PCHA forming a hair pin loop, traversing through lower triangular space instead of quadrangular space taking a long course is being reported for the first time. Further, the clinical and surgical importance of this case especially in relation with quadrangular space syndrome and relevant literature is discussed.