Anatomy, Shoulder and Upper Limb, Radial Nerve

The radial nerve is a peripheral nerve that provides motor and sensory function to the arm. The motor function innervates the posterior compartment of the arm including the medial and lateral heads of the triceps brachii muscles in addition to all 12 muscles in the posterior forearm compartment, as well as, the extrinsic extensor muscles found in the wrist and fingers. The sensory function provides cutaneous innervation to a portion of the anterolateral arm, distal posterior arm, posterior forearm, posterior aspects of the thumb, index finger, middle finger, and the lateral half of the ring finger. The radial nerve originates from the ventral roots of the spinal nerves C5-T1 of brachial plexus which eventually forms the posterior cord. Disruption of the radial nerve can have motor consequences such as an inability to extend the arm, wrist, and fingers and paresthesias about its sensory distribution.