Applied anatomical study of cubital tunnel syndrome

Abstract

Objective To investigate the anatomical elements of ulnar nerve compression at elbow, and provide guideline for surgical decompression. Methods Thirty-two upper limb specimens of 16 adult cadavers were dissected. Structures that can cause potential compression to the ulnar nerve at the elbow including arcade of Struthers, the medial intermuscular septum and cubital tunnel were measured observed. The cross-section area of the ulnar nerve at the cubital tunnel level and the cross-section area and length of the cubital tunnel were measured. Dimensions of the arcade ligament, the concomitant blood vessel of the ulnar nerve and the flexor carpi ulnaris branch of the ulnar nerve were also measured. Results Tendinous arcade of Struthers was seem in 12 limbs while muscular arcade of Struthers was found in 10 limbs. The incidence of arcade of Struthers was 68.8%. The ulnar nerve pierced the medial intermuscular septum (11.02±1.16)cm proximal to the medial epicondyle. The ratio of ulnar nerve cross-section area to cubital tunnel cross-section area was 1:3.86. The length of the cubital tunnel was (1.96±0.18)cm. The concomitant blood vessels of the ulnar nerve included superior ulnar collateral artery (SUCA) and posterior ulnar recurrent artery (PURA). The flexor carpi ulnaris branch of the ulnar nerve was diverged 1cm distal to the medial epicondyle. Conclusion Cubital tunnel was the most common compression site of the ulnar nerve. The incision of surgical decompression should be extended 11.02cm proximal to the medial epicondyle. Caution should be used to preserve PURA transposing the ulnar nerve anteriorly. Key words: Cubital tunnel syndrome; Ulnar nerve; Anatomy, regional; Muscle fibers