Ulnar Nerve Entrapment

Overview

The ulnar nerve is an important nerve because it supplies feeling to the little and ring fingers of the hand and activates many of the small muscles in the hand (allowing strong gripping of objects in the hand).

The ulnar nerve travels to the hand via the inside back part of the elbow where it can be bumped (hitting your “funny bone”). As it passes around the elbow it is exposed. Usually the tingling you get when bumping the nerve last a few seconds only but the ulnar nerve also can be the cause of more serious and permanent problems in the fingers and hand.

An injury to the elbow such as a dislocation or fracture can damage or irritate the ulnar nerve. The inflamed nerve can swell and become squashed in the cubital tunnel. This gives the condition its name, ulnar nerve entrapment (often also called cubital tunnel syndrome).

Prolonged pressure on the nerve also can be a problem. Bending the elbow stretches the ulnar nerve and squashes it as it passes through the cubital tunnel. This disrupts the nerve’s ability to conduct messages between the hand and the brain. The muscles of the hand gradually start to weaken (so that it becomes difficult to open a jar or hold a hammer) and you lose protective sensation on the inner part of the hand.

What to look for

Although the nerve is squashed around the elbow, most symptoms occur in the hand and fingers because the ulnar nerve controls movement and feeling.

You may experience:

• Tingling and numbness in little and ring fingers (especially at night).
• Numbness in your hand when the elbow is bent (holding the phone to your ear).
• Difficulty using your hand for day to day activities.
• Decreased grip and pinch strength and muscle weakness.
• Tenderness along the inside of the elbow.

Diagnosis

The majority of the diagnosis is in the history. Symptoms are often quite typical. You will need to have an x-ray to make sure there is no bone problem causing the nerve compression around the elbow. This is particularly important if you have had a fall, blow or other injury to the elbow.

You may be sent for nerve conduction studies to confirm the diagnosis or to act as a baseline test to monitor the nerve’s recovery. Click here to view information related to electromyography (EMG), a procedure used to evaluate the condition of nerves and muscles.

Nerve compression is more common following trauma, in diabetics, in people with arthritis or thyroid problems and in alcoholics but certainly not restricted to this group of people.

In the early stages of the nerve compression if there is no muscle wasting then it is feasible to treat the condition without an operation. If muscle wasting is present then surgical release of the squashed nerve should be undertaken as soon as practical. 

If you wish to avoid surgery follow these guidelines… 

• Keep the elbow as straight as possible. A straight elbow puts less pressure on the ulnar nerve.
• Avoid crossing your arms across your chest.
• Use a headset attachment for the telephone to avoid bending the elbow.
• Wear a splint at night. A towel wrapped around the elbow to help keep it straight is simple and cheap.
• If possible adjust your workspace so that you don’t have to bend your elbow more than 30 degrees and you can keep your wrist straight.

Surgery

If conservative treatment is not effective and muscle strength continues to weaken, further evaluation is needed. Do not wait until the muscles have wasted away prior to seeking treatment as this muscle “wasting” is often not reversible.

In cases where the ulnar nerve is chronically inflamed or entrapped, surgery may be required. There are several surgical options – the most frequent type of surgery moves the nerve from behind the bone to the front of the elbow. After the surgery, treatment must focus on maximising the use of the hand and arm through physiotherapy. This process can take several months.