In the upper arm and near the shoulder, the median nerve branches off of the brachial plexus. It runs the length of the upper arm, as it runs a course close to the brachial artery. Part of its course covers the medial side of the arm, near both the biceps brachii and brachialis muscle. For a large part of the course, the nerve runs lateral to the artery. However, it eventually crosses over and enters the cubital fossa of the elbow. The median nerve also extends along the forearm, through the carpal tunnel and it enters the hand. Since the nerve is so long, it contains many significant branches. It also innervates a number of muscles along the entire length of the arm. Also because of its length, the median nerve is susceptible to a number of conditions. This includes lesions causing median nerve palsy. If the nerve is completely severed, claw hand will result. Carpal tunnel syndrome of the hand can also result due to compression.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Median nerve