Causes / typical injury mechanism: In general, radial tunnel syndrome is caused by overuse of the elbow with prono-supination activities. This causes compression of the motor branch of the radial nerve (the posterior interosseus nerve) but manifests only as pain without motor or sensory changes.

Classic history and presentation: Classically, a young male doing repetitive prono-supination activities (with at least 1 kg of force and the elbow in 0-45 degrees of flexion) presenting with forearm and wrist pain, without motor or sensory changes.

Prevalence: 3 per 100 000 people per year in the United States

• Age – Second through fourth decade
• Sex / gender – More common in males

Risk factors: Repetitive prono-supination activities, labor-involving activities such as handling tools with full elbow extension.

Pathophysiology: Radial tunnel syndrome is caused by compression of the posterior interosseous nerve at either the leash of Henry, extensor carpi radialis brevis (ECRB) edge, arcade of Frohse, supinator muscle edge, or fibrous tissue between the brachialis and brachioradialis. Despite compression of a motor nerve, the manifestations are pain only, without motor or sensory changes. The mechanism behind this is poorly understood but is postulated to be caused by differential compression of group IV and IIA nerve fibers.