Radial Tunnel Syndrome
(Posterior Interosseous Nerve Syndrome)
(See also Overview and Evaluation of Hand Disorders.)
Symptoms of radial tunnel syndrome include lancinating pain in the dorsum of the forearm and lateral elbow. Pain is precipitated by attempted extension of the wrist and fingers and forearm supination. Sensory loss is rare because the radial nerve is principally a motor nerve at this level. This disorder is sometimes confused with backhand tennis elbow (lateral epicondylitis). When weakness of the extensor muscles is the primary finding, the condition is referred to as posterior interosseus nerve palsy.
Lateral epicondylitis can cause similar tenderness around the lateral epicondyle but does not cause the Tinel sign (paresthesia elicited by percussion over a nerve) or tenderness along the course of the radial nerve (which travels under the mobile wad group of muscles in the proximal radial forearm).