Identify the ulnar nerve [two probes] in the arm and trace its course from the axilla to the posterior aspect of the medial epicondyle of the humerus. Like the median nerve, the ulnar nerve does not supply any muscle in the arm. The ulnar nerve lies medial to the median nerve as it passes through the arm. In the lower portion of the arm, it pierces the intermuscular septum and then passes posterior to the medial epicondyle of the humerus. In the distal half of the arm, the ulnar nerve is accompanied by the superior ulnar collateral artery.
Above the elbow, the medial antebrachial cutaneous nerve divides into anterior and posterior branches that pass along the medial aspect of the forearm. The ulnar nerve, medial antebrachial cutaneous nerve and the medial brachial cutaneous nerve arise from the medial cord of the brachial plexus.
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