Systemization of the vascularization of the ulnar nerve in its upper arm.

Vascularized free nerve grafts make possible the repair of extensive defects of large nerve trunks. Since the original observations of Taylor and Ham in 1976 many cases have been published. The ulnar nerve in the upper arm in most cases has a simple arteriovenous pedicle the anatomy of which has been precisely defined by cadaver dissections and intravascular injections. The arterial supply, 47 times out of 50, is the proximal ulnar collateral and 2 times the distal collateral ulnar artery. It takes its origin from the medial side of the brachial artery in the upper or middle third of the arm. Its external diameter is on the average 1.8 mm at its origin. The accompanying vein enters a brachial vein 2 to 3 cm below the origin of the artery. The removal of the graft is done through a straight incision on the inner aspect of the arm. The brachial artery is dissected from above downward and its medial branches noted. The nerve and its arteriovenous pedicle are separated in a block along with adjacent cellular tissue by dissection from below upwards. The average length of the pedicle thus produced is 13 cm, but a much longer section of the nerve can certainly be taken. A case report illustrates the procedure.