Rare variation of the arm artery: coexistence with the superficial brachial and superficial subscapular arteries in the absence of the normal brachial artery.

A rare variation in the arterial pattern was found in the right arm of an 87-year-old male cadaver in a student dissection practice. In this case, the superficial brachial and superficial subscapular arteries coexisted in the absence of the normal brachial artery (A. brachialis profunda). After branching off a large-sized superficial subscapular artery, the axillary artery did not penetrate the brachial plexus and gave rise to a superficial brachial artery, which arose from the axillary artery at the point between the ansa pectoralis and ansa mediana, and descended ventral to the median nerve branching off the profunda brachii and superior and inferior ulnar collateral arteries. The superficial brachial artery finally divided into the radial and ulnar arteries in the cubital fossa. The superficial subscapular artery passed inferior and dorsal to the medial cord of the brachial plexus, giving off the lateral thoracic artery, and then branched off into the thoracodorsal, circumflex scapular and posterior circumflex humeral arteries. Thus the main nerves of the brachial plexus were sandwiched between the superficial brachial artery and the superficial subscapular artery system. The morphological and clinical significance of this variant are discussed.