Syndrome of the Musculocutaneous Nerve at the Elbow

Originating from the lateral cord of the brachial plexus, the musculocutaneous nerve supplies motor branches to the coracobrachialis, biceps brachii, and brachialis muscles and sensory branches to portions of the forearm and wrist. The lateral cord of the brachial plexus crosses into the axilla before dividing into the musculocutaneous nerve and contributing to the median nerve. The musculocutaneous nerve stays lateral to the axillary artery and lies on the coracobrachialis before piercing through the muscle. In about 10% of the cases, the nerve does not pierce the muscle’s fascia. The nerve then continues to run between the biceps brachii and brachioradialis muscles before piercing the brachial fascia 2 to 5 cm proximal to the medial cubital crease.