The symptoms of radial tunnel syndrome closely resemble tennis elbow, although the cause is different. Radial tunnel syndrome is caused when the nerve that operates several muscles around the wrist and hand (the posterior interosseous nerve) is compressed, or pinched. This causes weakness of the muscles supplied by the nerve and pain over the elbow where the compression takes place.
Radial tunnel syndrome is not unlike carpal tunnel syndrome, although a different nerve is pinched and different symptoms result. Radial tunnel syndrome usually causes pain about 4 cm beyond the bony prominence on the outside of the elbow. Sometimes an EMG is obtained to diagnose radial tunnel syndrome, but this can be normal.