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Radial Tunnel Syndrome

(Posterior Interosseous Nerve Syndrome)

By David R. Steinberg, MD, Associate Professor, Department of Orthopaedic Surgery, and Director, Hand and Upper Extremity Fellowship, Perelman School of Medicine at the University of Pennsylvania

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Radial tunnel syndrome is compression of the radial nerve in the proximal forearm. Symptoms include forearm and elbow pain. Diagnosis is clinical. Treatments include splinting and sometimes surgical decompression.

Compression at the elbow can result from trauma, ganglia, lipomas, bone tumors, or radiocapitellar (elbow) synovitis.

Symptoms and Signs

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.


  • Clinical evaluation

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).


  • Splinting

Splinting allows avoidance of the forceful or repeated motion of supination or wrist dorsiflexion, reducing pressure on the nerve.

If wristdrop or weakened digital extension develops, or conservative treatment fails to provide relief after 3 mo, surgical decompression may be needed.