Median nerve

A critical nerve in the arm responsible for sensation and movement in certain hand areas.

The median nerve is one of the major nerves of the upper limb. It originates from the brachial plexus, specifically from the medial and lateral cords, carrying fibers from spinal nerve roots C5, C6, C7, C8, and T1. It primarily supplies sensory and motor function to parts of the hand and forearm, playing an essential role in the coordination of movements.

Terminologia Anatomica

nervus medianus

System

Nervous system

Function

The median nerve has an essential function in the body, facilitating both sensory and motor pathways. It innervates several muscles in the forearm, including the flexor muscles that are responsible for bending the wrist and fingers. This capability allows for precision grips necessary for tasks such as writing and typing. In addition to motor functions, the median nerve carries sensory information from the palmar side of the thumb, index, middle, and part of the ring finger, as well as the nail beds of these areas. An injury to this nerve can lead to a diminished ability to perform delicate tasks, reflecting its vital role in daily activities.

Location

The median nerve follows a specific pathway through the arm and hand. It begins in the upper arm where it arises from the brachial plexus and travels down into the forearm by passing between the two heads of the pronator teres muscle. As it continues down the forearm, it runs alongside the flexor carpi radialis and enters the carpal tunnel at the wrist. Within this tunnel, the median nerve is situated beneath a fibrous band, the transverse carpal ligament. Its final destination is in the hand, where it branches out to supply the thenar muscles and the aforementioned sensory regions, completing its circuit from the shoulder to the fingertips.

Did You Know?

Carpal tunnel syndrome, a condition caused by compression of the median nerve, can lead to numbness and pain in the hand.
The median nerve is the only nerve that crosses from the forearm into the hand, making it essential for hand function.
In addition to sensory and motor functions, the median nerve is involved in the fine motor tasks that require precision.
The median nerve also plays a role in the reflexes that protect the hand from harmful stimuli.