The musculocutaneous nerve branches from the lateral cord of the brachial plexus. It supplies the anterior compartment of the arm, and sensation to the lateral forearm.

The musculocutaneous nerve (C5-7) is a terminal branch of the lateral cord. It supplies the flexor compartment of the arm i.e. biceps brachii (both long and short heads, the muscle acts as a supinator of the forearm and flexor of the elbow), coracobrachialis (adducts and flexes the shoulder) and brachialis (the primary elbow flexor).

It initially follows the course of the third part of the brachial artery and then pierces the coracobrachialis muscle, 3-8cm distal to the coracoid process. It then continues down the arm, behind biceps and in front of brachialis, giving branches to both muscles as it descends. The nerve then continues down and pierces the fascia attaching to the lateral aspect of the biceps brachii tendon, 2 cm above the elbow. It then continues distally where it terminates as the lateral cutaneous nerve of the forearm. 

Developmental precursor- Alar and basal plate of C5-C7 spinal nerves

Origin- C5-C7

Branches- Lateral cutaneous nerve of the forearm.

Muscles supplied- coracobrachialis, bicep brachii, brachialis

Dermatome- Lateral forearm

The biceps comes to mind when we thing of muscular, so the musculocutaneous nerve can be remembered as supplying the compartment of the definitive muscle i.e. biceps brachii.

 

The name musculocutaneous also implies that the nerve has a muscular role, and a sensory role as the lateral cutaneous nerve of the forearm.

The musculocutaneous nerve is a branch of the brachial plexus. It supplies the anterior compartment of the arm, and sensation to the lateral forearm.

Authors; S Shahid, A Davies