Cubital tunnel syndrome is a disorder caused by compression of the ulnar nerve at the elbow.
The ulnar nerve passes close to the surface of the skin at the elbow (“funny bone”) and is easily damaged by repeatedly leaning on the elbow, by bending the elbow for prolonged periods, or sometimes by abnormal bone growth in the area. It is less common than carpal tunnel syndrome. Baseball pitchers are prone to cubital tunnel syndrome because of the extra twist of the arm required to throw a slider.
Symptoms include numbness and a pins-and-needles sensation of the ring and little fingers and pain in the elbow. Eventually, weakness of the hand, particularly of the ring and little fingers, may develop. Weakness may also interfere with the ability to pinch using the thumb and index finger and the ability to grip with the hand because most of the small muscles in the hand are controlled by the ulnar nerve. Severe, chronic cubital tunnel syndrome can lead to muscle wasting (atrophy) and a clawlike deformity of the hand.
Doctors base the diagnosis on an examination, but nerve conduction studies (see see Electromyography and Nerve Conduction Studies) may be needed to help pinpoint the exact area of nerve damage, especially if surgery is being considered. People with mild cases of cubital tunnel syndrome undergo physical therapy (including wearing a splint at night to avoid overbending the elbow) and avoid pressure over the elbow. An elbow pad worn during the day can be helpful. About 85% of people who do not respond to splinting or who have more severe cases of nerve compression may benefit from surgery, which usually consists of releasing pressure on the nerve.
Last full review/revision September 2013 by David R. Steinberg, MD