Atypical Division of the Axillary Artery into Superficial and Deep Systems with Altered Neurovascular Relationships in the Arm

Variations in the branching pattern of the axillary artery are well documented and clinically significant due to their implications in surgical and interventional procedures. A rare unilateral variation observed during routine dissection of a 54-year-old male cadaver was found. On the right side, the axillary artery divided at its second part, distal to the thoracoacromial trunk, into a superficial brachial artery (SBA) and a deep trunk. The deep trunk was located between the medial and lateral roots of the median nerve and gave rise to the profunda brachii artery, a common trunk for the subscapular and lateral thoracic arteries, and muscular branches to the posterior axillary wall. The profunda brachii artery further gave origin to the anterior and posterior circumflex humeral arteries. The SBA coursed anterior to the median nerve, remained branchless in the arm, and terminated in the cubital fossa by dividing into radial and ulnar arteries. The variation was unilateral; the left side showed normal anatomy. This rare combination of arterial variation with altered neurovascular relationships may increase the risk of vascular injury during axillary lymph node dissection, brachial plexus surgery, and regional anesthesia. Awareness of such patterns is essential for safe surgical practice.