Understanding Ulnar Neuropathy

More Than Just Tennis Elbow

Fingers Typing
Fingers Typing. Michael Smith / Staff / Getty Images

A thirty year-old computer programmer noticed that his typing was being interrupted by feelings of tingling and numbness in his little finger and part of his ring finger. These feelings were worse in the morning and after he rested his elbows on his desk to type. The symptoms slowly worsened over a month. What was going on?

Did you ever hit your "funny bone" and feel that electrical shock travel down your arm into your fingers?

Chances are you briefly felt what the programmer had for the last month -- a brief ulnar neuropathy.

Nerves of the Hand

The hand receives its peripheral nerve supply from three main nerves: the radial, median, and ulnar nerves. These nerves run from the hand to the neck, where they interweave in the brachial plexus. Electrical information is then sorted into nerve roots that enter the spinal cord, and travel to the brain.

Each of the three main nerves has a different function in the hand. The radial nerve is responsible for sensation to most of the back of the hand, as well as straightening out the fingers. The median nerve gives sensation to most of the thumb and first two fingers, as well as flexing the first two fingers and thumb.

The ulnar nerve is responsible for sensation for the front and back of the little finger and part of the ring finger. It also flexes those two fingers, and allows you to fan your fingers apart and together.

The term "ulnar neuropathy" just means that something is wrong with the ulnar nerve. Usually this is nothing more than something pressing on the nerve. The most obvious example is when you hit your elbow and feel that annoying twinge down your arm.

As nerves course down the arm, they sometimes pass through tight regions in which they are more subject to damage than elsewhere in the arm.

The two most common places for ulnar nerve compression are the elbow and the wrist.

Types of Ulnar Neuropathies

The medical term for "funny bone" is the medial epicondyle of the elbow, where the ulnar nerve passes in a narrow place called the ulnar groove. The nerve can be irritated by trauma such as a fracture, or by chronic inflammation caused by overuse (such as in tennis elbow), or by habitually resting the elbows on a hard table.

Symptoms of an ulnar neuropathy due to entrapment at the elbow include numbness of the little finger and part of the ring finger, and sometimes the edge of the hand as well. The two fingers may also be weak, and there may be less ability to fan out the fingers. In the case of entrapment at the elbow, there may be discomfort down the forearm as well.

The ulnar nerve can also be compressed in a narrow area called Guyon's canal in the hand. This is most common in bicyclists who lean over the handlebars for a prolonged period of time. This leads to the same pattern of weakness as seen in ulnar entrapment at the elbow.

There is no sensory loss, however, because those nerve fibers branch out before the nerve goes into the canal.

Diagnosis and Treatment

Often, no more than a physical examination is needed to confirm a diagnosis of ulnar neuropathy. Sometimes a doctor may want to confirm the diagnosis with an electromyogram or nerve conduction studies.

The first line of treatment is to relieve any inflammation that might be compressing the nerve. This involves a combination of rest, proper mechanics, and sometimes supportive splinting. In the case of the computer programmer, just using elbow pads on his desk at work was sufficient. If symptoms fail to improve, doctors may be able to offer other treatment options, including medication or surgical decompression.


Hal Blumenfeld, Neuroanatomy through Clinical Cases. Sunderland: Sinauer Associates Publishers 2002

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