The thumb is very important when gripping or manipulating objects.

Descriptions of the anatomical movements of the thumb often become confused. Here we can review the movements of the thumb in relation to the muscles that perform the movements and the nerves that innervate those muscles.

Nerves of the forearm supply motor innervation to the muscles moving the fingers and thumb. The nerves of the forearm are the ulnar, median and radial nerves.

Broadly speaking, branches of the median nerve innervate flexor muscles of the anterior forearm and muscles at the thumb (thenar eminence), the ulnar nerve supplies the muscles at the little finger (hypothenar eminence), and branches of the radial nerve innervate the extensor muscles of the posterior forearm.

Movements of the thumb:

- Overview
- Abduction
- Adduction
- Flexion
- Extension

Your knowledge of the contribution of the ulnar, median and radial nerves to the movements of the thumb and fingers will help you diagnose problems with grip, for example, or to examine the effects of an injury to the upper limb that may affect one or more of these nerves.

You should use your anatomy textbooks to learn about the details of the muscles and motor innervation in the hand.