Brachioradialis muscle pain: a common source of underdiagnosed or misdiagnosed forearm pain.

The brachioradialis (BR) muscle is a long, large, fusiform muscle on the lateral side of the forearm. It originates from the lateral distal humerus and inserts to the base of the styloid process of the radius. The function of the BR muscle is to flex the elbow, especially with the hand in a neutral position, to pronate and supinate the forearm, and to support wrist extension, especially gripping or picking up something. BR muscle pain arises from repetitive overuse, sudden overloading, and direct blow. Common painful daily activities include putting a cup back down after drinking, opening doors, shaking hands, and using a screwdriver or hammer. The two most common symptoms of BR muscle pain are a sharp and shooting pain during activity and an aching pain at rest from the lateral elbow through the forearm, back of the hand, and thumb and index finger, as well as tightness. Differential diagnosis considers lateral epicondylitis (tennis elbow), radial tunnel syndrome, de Quervain's tenosynovitis, carpal tunnel syndrome, trigger thumb, writer's cramp, and cervical radiculopathy. BR muscle pain is common in patients with subacromial impingement syndrome. Basic conservative treatment includes rest, ice, compression, and elevation (RICE), as well as medication. Stretching exercise for the BR muscle is helpful. Injection techniques, such as myofascial injection or botulinum muscle injection, are also recommended. BR muscle pain is one of the common sources of underdiagnosed and misdiagnosed forearm pain.