VASCULAR ANATOMY OF THE ULNA

The vascular anatomy of the ulna was studied. Ten fresh-frozen upper e xtremity specimens were injected with India ink and latex solution. Th e extraosseous anatomy was dissected. The intraosseous anatomy was eva luated after treatment with the modified Spalteholtz technique. The pr oximal periarticular portion of the ulna was supplied by numerous, ver y small periarticular branches running in the capsule. A major intrame dullary nutrient vessel arose from the ulnar artery or ulnar recurrent artery in all specimens and entered at the base of the coronoid. The ulnar artery gave off a common interosseous artery that branches into posterior and anterior interosseous vessels that course distally on th e interosseous membrane. The interosseous vessels were critical for th ey supply the only observed vascular branches to the ulna diaphysis. T he anterior interosseous vessel supplied on average 7 branches (range, 3-11 branches) to the ulna diaphysis spaced at generally regular 2-cm intervals, with the number of branches decreasing in the distal third . The posterior interosseous artery supplied an average of 11 branches (range, 9-14 branches) to the ulna diaphysis spaced at l-cm intervals . The distal ulna metaphysis was supplied by terminal branches of the anterior interosseous artery. The ulnar head was supplied by small bra nches off the ulnar artery proper. In summary, the blood supply to the ulna diaphysis was dependent on segmental vessels provided by the ant erior and posterior interosseous vessels. No dominant intramedullary v essel was observed in the diaphysis. The interosseous vessels should b e protected when treating a ulna Fracture or a nonunion, or when perfo rming an osteotomy. Copyright (C) 1998 by the American Society For Sur gery oi the Hand.