Hello again, everyone. This is Matt from Kenhub! And in this short tutorial, we will discuss the anatomy, innervation, and distribution of the radial nerve.
The radial nerve serves as nerve supply for some muscles of the upper arm and most of the extensors of the forearm. This nerve is the direct continuation of the posterior cord of the brachial plexus.
It courses between the brachioradialis and the brachialis to the elbow where it divides into a deep branch and a superficial branch at the level of the radial head.
The superficial branch uses the brachioradialis as a guiding structure to reach the wrist joint and arrives at the dorsum of the hand.
In contrast, the deep branch penetrates the supinator muscle and continues to the extensors of the forearm. It is important to note that the branches supplying the brachioradialis and extensor carpi radialis longus branch off before the division of the radial nerve, whereas the nerve supplying the extensor carpi radialis brevis, the posterior interosseus nerve arises just after the division.
The radial muscles this nerve supplies are the brachioradialis muscle, the extensor carpi radialis longus, and the extensor carpi radialis brevis. The radial musculature supports movements of the elbow, hand, and radioulnar joints.
The brachioradialis is mainly responsible for the lateral contour of the elbow and forearm.
The extensor carpi radialis longus and the extensor carpi radialis brevis function as the dorsal extensors and the radial abductors of the wrist joint. They also contribute to a strong fist closure by stretching the flexor muscles of the hand and fingers prior to contraction.