Musculocutaneous nerve

Musculocutaneous nerve

Anatomy

Course
A terminal branch of the lateral cord of the brachial plexus. It exits the axilla, piercing the coracobrachialis muscle, to pass between the biceps brachii and brachialis muscles in the anterior compartment of the arm.

It continues distally towards the elbow, and crosses into the forearm over the lateral epicondyle of the humerus. It then continues on through the forearm as the lateral antebrachial cutaneous nerve.

Supply

Provides motor innervation to the muscles in the anterior compartment of the arm, i.e. the biceps brachii, the brachialis, and the coracobrachialis muscle.

Clinical

Damage to the nerve will result in an absence of the biceps reflex. This is tested by tapping the tendon of the biceps brachii at the elbow, to produce a sharp jerk-like movement in the forearm as the biceps brachii flexes at the elbow joint.

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