Cubital Tunnel Syndrome
Cubital Tunnel Syndrome is a condition that involves pressure or stretching of the ulnar nerve (also known as the “funny bone” nerve), which can cause numbness or tingling in the ring and small fingers, pain in the forearm, and/or weakness in the hand. The ulnar nerve (Figure 1) runs in a groove on the inner side of the elbow.
Causes
There are a few causes of this ulnar nerve problem. These include:
- Pressure: The nerve has little padding over it. Direct pressure (like leaning the arm on an arm rest) can press the nerve, causing the arm and hand — especially the ring and small fingers — to “fall asleep.”
- Stretching: Keeping the elbow bent for a long time can stretch the nerve behind the elbow. This can happen during sleep.
- Anatomy: Sometimes, the ulnar nerve does not stay in its place and snaps back and forth over a bony bump as the elbow is moved. Repeated snapping can irritate the nerve. Sometimes, the soft tissues over the nerve become thicker or there is an “extra” muscle over the nerve that can keep it from working correctly.
Signs and Symptoms
Cubital tunnel syndrome can cause pain, loss of sensation, tingling and/or weakness. “Pins and needles” usually are felt in the ring and small fingers. These symptoms are often felt when the elbow is bent for a long period of time, such as while holding a phone or while sleeping. Some people feel weak or clumsy.
Diagnosis
Your doctor can learn much by asking you about your symptoms and examining you. S/he might test you for other medical problems like diabetes or thyroid disease. Sometimes, nerve testing (EMG/NCS) may be needed to see how much the nerve and muscle are being affected. This test also checks for other problems such as a pinched nerve in the neck, which can cause similar symptoms.
Treatment
The first treatment is to avoid actions that cause symptoms. Wrapping a pillow or towel loosely around the elbow or wearing a splint at night to keep the elbow from bending can help. Avoiding leaning on the “funny bone” can also help. A hand therapist can help you find ways to avoid pressure on the nerve.
Sometimes, surgery may be needed to relieve the pressure on the nerve. This can involve releasing the nerve, moving the nerve to the front of the elbow, and/or removing a part of the bone. Your surgeon will talk to you about options.
Therapy is sometimes needed after surgery, and the time it takes to recover can vary. Numbness and tingling may improve quickly or slowly. It may take many months for recovery after surgery. Cubital tunnel symptoms may not totally go away after surgery, especially if symptoms are severe.
© 2015 American Society for Surgery of the Hand
This content is written, edited and updated by hand surgeon members of the American Society for Surgery of the Hand. Find a hand surgeon near you.