Musculocutaneous nerve

Medically reviewed by Healthline Medical Team on February 27, 2015Published on February 27, 2015

The musculocutaneous nerve innervates the muscles in front portion of the arm. These include the coracobrachialis, the biceps brachii, and the brachialis. The nerve originates from spinal nerve roots C5, C6, and C7. It extends out of the lateral cord of the brachial plexus, a network of nerves that allows signals to travel from the spine to the shoulder, arm, and hand. It enters the coracobrachialis muscle close to where the muscle inserts on the humerus. The nerve travels down the outside of the arm between the brachialis and biceps brachii. It emerges on the outside of the biceps tendon. It continues down the forearm to become the lateral cutaneous nerve. Here, it innervates the skin on the lateral aspect of the forearm. This is the area of the forearm that is furthest from the body’s midline. The musculocutaneous nerve is prone to unusual variations. For example, it sometimes interacts with the median nerve, with branches forming between the two nerves. The musculocutaneous nerve can be damaged by compression, leading to loss of sensation on the outside of the forearm. This type of damage can occur during activities like weight lifting. Some people who experience this type of injury may spontaneously recover after a few months, but others may require therapy. Damage to the shoulder or brachial plexus may also affect the nerve.

CMS Id: 141070