Regional anatomic structures of the elbow that may potentially compress the ulnar nerve

Abstract

Hypothesis: Traumatic injuries to the ulnar nerve at the elbow are a frequent problem as it is vulnerable to stretching and compression with motion of the upper limb. The aim of the present study was to explore the course of the ulnar nerve at the elbow and forearm and to determine possible anatomical structures that may cause compression of this structure.

Materials and methods: We examined 12 upper limbs from cadavers. The length of any fibrous bands, and if present, their distance to the medial epicondyle was recorded.

Results: On 5 sides a fibrous band originating from the medial intermuscular septum was observed to cross over the ulnar nerve. The average length of the fibrous band was 5.7 cm, and it attached to the medial epicondyle. The mean length of the ulnar nerve as it coursed in the cubital tunnel was 3.8 cm. In 4 of the cases, the ulnar nerve was covered by muscle fibers originating from the flexor digitorum superficialis and extending to the flexor carpi ulnaris. On 5 sides we observed fibrous thickenings, and on 8 sides vascular structures were found crossing over the ulnar nerve.

Discussion: The cubital tunnel is the most common site of compression of the ulnar nerve. Numerous surgical procedures are recommended for cubital tunnel syndrome. Simple decompression is used most commonly. Although surgical procedures are reported to provide efficient pain relief and functional recovery, residual or recurrent symptoms have been reported. Reasons for such recurrences may be more proximal or distal compression of the ulnar nerve as seen in our study.

Conclusion: Knowledge of possible compression sites of the ulnar nerve is important to the surgeon so that complications are avoided and postoperative recurrence is decreased.

Level of evidence: Basic science study.