Anatomy

Over the proximal course, the median nerve is adjacent to the brachial artery.

After the elbow crease, the nerve moves away from the artery, running deeper before entering the pronator tunnel.

In the distal forearm the median nerve runs in between the flexor digitorum muscles and becomes more and more superficial in its distal course.

In the wrist crease the nerve lies between the flexor tendons superficially and is recognised by its typical honeycomb structure.

Distal to the wrist crease the nerve descends into the carpal tunnel and runs directly underneath the retinaculum flexorum.

As the nerve emerges from the tunnel, the thenar and hypothenar muscles become visible and the nerve divides into its digital branches.

There are two main entrapment sites of the median nerve: the pronator tunnel and the carpal tunnel.