The Musculocutaneous Nerve
Definition
The musculocutaneous nerve is a major peripheral nerve of the upper limb
The musculocutaneous nerve innervates – the biceps brachii, brachialis and coracobrachialis. These muscles flex the upper arm at the shoulder and the elbow. In addition the biceps brachii also performs supination of the forearm.
Arises from the lateral cord of the brachial plexus, opposite the lower border of the Pectoralis minor. Fibers derived from C 5,6,7 roots
Muscle (Motor) innervated
the muscles in the anterior compartment of the arm
It innervates the Biceps brachii, Brachialis & Coracobrachialis (BBC)
Sensory innervation
Gives rise to the lateral cutaneous nerve of forearm, which innervates skin on the lateral surface of the forearm.
Course of the nerve
It penetrates the Coracobrachialis muscle
Passes between the Biceps brachii and the Brachialis
Passes to the lateral side of the arm
It is continued into the forearm as the lateral antebrachial cutaneous nerve.
Applied anatomy
Isolated injury, causes weakness of elbow flexion & supination of the forearm.
A sensory disturbance is on the radial side of the forearm.
The nerve is usually involved in an upper brachial plexus palsy
