Radial nerve anatomy

The radial nerve is one of the major nerves in the human arm. It originates from the brachial plexus, carrying fibers from the ventral roots of spinal nerves C5, C6, C7, C8 & T1.

Here is a step-by-step breakdown of the radial nerve anatomy:

1. Origin: The radial nerve originates from the posterior cord of the brachial plexus, with roots from the C5-T1 nerve fibers.

2. Course: It descends down the arm, passing through the triangular interval (an area bordered by the teres major, the long head of the triceps brachii, and the humerus) to enter the posterior compartment of the arm.

3. Branches in the Arm: In the posterior compartment of the arm, it gives off branches to the triceps brachii and anconeus muscles, as well as the cutaneous branches to the skin of the arm.

4. At the Elbow: The nerve winds around the humerus, running in the spiral groove along with the profunda brachii artery. It then pierces the lateral intermuscular septum to reach the anterior compartment of the arm, just above the elbow.

5. Forearm and Hand: It continues its course down the forearm, giving off branches to the extensor muscles of the forearm and the skin of the hand. It terminates as the superficial radial nerve, supplying the dorsolateral part of the hand, and the deep radial nerve, which becomes the posterior interosseous nerve, supplying the extensor muscles of the forearm.

6. Motor Functions: The radial nerve supplies all the muscles in the posterior compartment of the arm and forearm, which are primarily responsible for extension at the elbow, wrist, and fingers.

7. Sensory Functions: It provides sensory innervation to the skin of the posterior arm, forearm, and the dorsolateral part of the hand.

Damage to the radial nerve can result in loss of motor function, causing wrist drop, and loss of sensation in the areas supplied by the nerve.