Neurolysis in Ulnar Nerve Entrapment Syndromes

Abstract

The ulnar nerve is the largest branch of the medial cord of the brachial plexus. Running behind the axillary vessels, it is the most posterior structure in the medial side of the arm. It generally also receives a branch from the lateral cord (C6, C7), which is the motor supply to the flexor carpi ulnaris (FCU) in the forearm. In the distal third of the arm, after having pierced the medial intermuscular septum, it is accompanied by the ulnar collateral artery and lies in front of the branch of the radial nerve to the medial head of the triceps muscle, formerly known erroneously as the ulnar collateral nerve. It leaves the arm without supplying a branch and lies in the ulnar groove of the humerus behind the medial epicondyle in direct contact with the bone. It is retained in the olecranon groove under a cover of fibrous tissue originating from the common flexor muscle.