The musculocutaneous Nerve

Question 1

What are the spinal roots of the musculocutaneous nerve?

Answer 1

C5-C7

Question 2

What are the motor functions of the musculocutaneous nerve?

Answer 2

Innervates the muscles in the anterior compartment of the arm

Question 3

Which muscles are within the anterior compartment of the arm?

Answer 3

Biceps brachii, Brachialis and Coracobrachialis (BBC)

Question 4

What do the muscles within the anterior compartment do?

Answer 4

They all flex the upper arm at the shoulder and elbow.

Biceps brachii also performs supination of the forearm

Question 5

What part of the brachial plexus is the musculocutaneous nerve a continuation of?

Answer 5

The lateral cord hence it contains fibres from the C5, C6 and C7 spinal roots

Question 6

What is the anatomical course taken by the musculocutaneous nerve?

Answer 6

• It leaves the axilla and pierces coracobrachialis, near the muscle’s point of insertion on the humerus
• It then passes down the arm anterior to brachialis but deep to biceps brachii, innervating them both
• It emerges laterally to the biceps tendon and continues into the forearm as the lateral cutaneous nerve

Question 7

Which areas of the skin does the musculocutaneous nerve provide sensation?

Answer 7

It gives rise to the lateral cutaneous nerve within the forearm which innervates the skin on the lateral surface of the forearm. It pierces the fascia to become subcutaneous and can be found in close proximity to the cephalic vein