Ulnar Nerve Passing Through the Gap Created by the Chiasma Between Brachial and Basilic Veins: Clinical Significance

The anatomical variations in the tributaries pattern of the axillary vein are not uncommon. In this case report, we describe three distinct findings observed in the right upper limb of a 65-year-old male cadaver: (1) a venous chiasma formed between the common brachial and basilic veins in the middle of the arm, (2) the variant course of ulnar nerve passing deep into the gap created by the chiasma, and (3) the cephalic vein terminating in the basilic vein. The knowledge of such variations could be resourceful for surgeons in avoiding neurovascular damage during basilic vein catheterization and anticipating difficulty in creating the brachio-basilic arteriovenous fistula.