Intersection syndrome of the forearm is a common painful condition that is infrequently diagnosed. It presents with pain and swelling in the area where the muscle bellies of the abductor pollicis longus and extensor pollicis brevis cross the common wrist extensors. The etiology is not well understood, but operative treatment of 13 patients has shown that the basic pathologic abnormality is stenosing tenosynovitis of the sheath of the common radial wrist extensors.