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Ulnar Neuropathy
Ulnar neuropathy means damage to the ulnar nerve. The ulnar nerve is one of the three main nerves that travel down the arm. It originates from the spinal cord in the neck, passes down the length of the arm and provides sensation to the little finger and half of the ring finger. It also controls most muscle movement in the hand. The ulnar nerve can be damaged anywhere along its length, but the most frequent place is where it passes through the elbow. Another vulnerable area is where it passes through the wrist.
In the elbow it goes along a groove and through a narrow channel, the cubital tunnel. This groove, anatomically known as the olecranon notch, can be felt just behind the bony protuberance on the inside of the elbow. If you have ever experienced the sensation caused by hitting your elbow on your ‘funny bone’, you have momentarily compressed the ulnar nerve as it goes through this channel. It is vulnerable to damage at this point as it lies between skin and bone and is not protected by muscle, tendons or fat. It is also stretched every time the elbow is bent.
At the wrist, the ulnar nerve travels through another narrow channel known as Guyon’s Canal. Due to the limited space available, the nerve is vulnerable to compression at this point.
Damage to the ulnar nerve, if not treated, can result in muscle wasting (atrophy) in the hand that can be permanent.
Causes:
There are many ways of damaging the ulnar nerve. If the injury is in the elbow, simply leaning on the elbow too much might be the reason. Excessive bending of the elbow might overstretch the nerve, or it might be compressed by the swelling of tissues near it. With some people the nerve naturally moves out of the olecranon notch when the elbow is bent, which, over time, could cause irritation.
A previous, surgically repaired, injury to the elbow might have changed the anatomy enough to abnormally press on the nerve, or the neuropathy might be a result of a wider problem, such as diabetes or alcoholism, both of which damage the entire nervous system.
Symptoms:
The ulnar nerve is actually a bundle of individual nerve fibers. Some fibers are responsible for transmitting sensations from the fingers to the brain and spinal cord, while others send instructions from the brain and spinal cord to most of the muscles in the hand and some in the forearm. Depending on which particular fibers are damaged, symptoms may include:
- Numbness or tingling (‘pins and needles’) in the little and ring fingers
- Numbness or tingling in the heel of the hand
- Weakness in the hand when performing fine motor movements, straightening the ring and little fingers, and spreading the fingers
- Muscle atrophy
These symptoms may be intermittent and may only be noticeable when the elbow is bent, or during the night.
Diagnosis:
Your doctor will ask you about your medical history, your general health, lifestyle, and normal activities. You may be asked questions about the way you sleep, as the position of your elbows during sleep can affect the ulnar nerve. You will be asked about your current symptoms, their onset, severity, and duration.
Your arm will be physically examined, moved and touched in specific ways to help with the diagnosis. Your neck and shoulder will also be moved to see if different positions produce symptoms. Your hand will be tested for sensitivity and strength. Although X-rays will not show the ulnar nerve, one may be ordered to see if there is a physical reason for the neuropathy such as a bone spur, arthritis or a cyst. A nerve conduction test might be performed to determine the location of the damage. Nerve impulses are electrical and take a certain amount of time to reach their destination. Measurements taken at different points along the arm can reveal abnormally slow nerve activity, which would suggest damage at that point.
Treatment:
Most nerve damage heals by itself with conservative (non-surgical treatment), so if your injury is relatively mild, conservative treatment would be the initial course.
Treatment would consist of wearing a padded splint or brace over the elbow or wrist, depending on the location of the injury, with the padding placed over the olecranon notch of the elbow, or ulnar side of the wrist. This would protect the nerve and prevent overstretching it. You could take anti-inflammatory pain medication, such as ibuprofen, to help with your symptoms. Steroid injections are not recommended for ulnar neuropathy as they can damage the nerve further.
If the pain is too severe, if conservative measures fail, or if muscle atrophy is significant, surgery can be performed. Most surgical procedures for ulnar neuropathy are done on an outpatient basis, that is, you would not have to spend the night in hospital. If the cause of your neuropathy is that either the cubital tunnel or Guyon’s Canal is too narrow, the constricting tissues can be surgically released. Scar tissue would then form, healing the tissues and providing an enlarged space through which the nerve could pass. Occasionally it might be necessary to move the ulnar nerve from the olecranon notch to a position where it is protected and can no longer be leant on or stretched when the elbow is bent. This procedure is called an ulnar nerve anterior transposition. You would have to wear a splint for a few weeks post-operatively, and physical therapy in the form of exercises would help you regain flexibility and strength in your hand.
Prognosis:
The results of treatment for ulnar neuropathy are normally good. Nerve regeneration is slow, so recovery can take some time. If the nerve compression was particularly bad there may be some residual damage, in which case any muscle atrophy would be permanent.
Exercises:
Your physical therapist or doctor will advise you about rehabilitation, but the exercise below may prevent stiffness in your arm and wrist and ease symptoms.
Hold your arm straight out in front of you. Keeping the elbow straight, curl your fingers and wrist towards you then stretch them in the opposite direction so the wrist is bent away from you and the fingers are pointing to the floor. With the fingers still extended, bend the elbow.
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