A Cadaveric Study on Variations of Branching Patterns of Ulnar Nerve in Hand

Introduction: Anatomical knowledge of variations in the branching patterns of ulnar nerve in hand is very important for the surgeons in diagnosis of peripheral neuropathies and in treating nerve compression syndromes. In addition, knowledge of relationship between deep branch of ulnar nerve and deep palmar arch is important in treating ulnar nerve compression due to post-traumatic pseudo aneurysm, true aneurysm of distal ulnar artery or tortuous ulnar artery. Aim: To observe the division of ulnar nerve in relation to flexor retinaculum, the variations in the branching patterns of ulnar nerve in hand and the relation between deep branch of ulnar nerve and deep palmar arch. Materials and Methods: An observational study was conducted in 52 cadaveric hands collected from Department of Anatomy, Chettinad Hospital and Research Institute from August 2013 to Dec 2013. Specimens were fixed in 10% of formalin and dissected. Observations were noted. Results: Division of ulnar nerve into superficial and deep branch was seen along the middle part of flexor retinaculum in 15 (28.8%) out of 52 specimens. In 5 (9.6%) out of 52 specimens, this division was seen in the distal part of flexor retinaculum. Trunk of ulnar nerve supplying abductor digiti minimi was seen in 5 (9.6%) specimens and accessory abductor digiti minimi in 3 (5.7%) specimens. Superficial branch of ulnar nerve supplying abductor digiti minimi in five specimens and flexor digiti minimi in three specimens. Deep branch of ulnar nerve was seen along the concavity of deep palmar arch in 15 (28.8%) specimens and along the convexity in 23 (44.2%) specimens. In 14 (26.9%) specimens, deep branch of ulnar nerve was seen crossing the deep palmar arch superficially from proximal to distal. Conclusion: Ulnar nerve presents with many variations in the hand. These variations may lead to entrapment neuropathies which will have varied presentations. Knowledge of these variations will help the general surgeons, orthopedic surgeons and plastic surgeons during various surgical corrections.