Carpal Tunnel Syndrome Quiz: Test Your Medical IQ

Carpus is a word derived from the Greek word karpos, which means "wrist." The carpal tunnel is the passageway in the wrist that is made up of the arching carpal bones and the ligament connecting the pillars of the arch. The median nerve and the tendons that connect the fingers to the muscles of the forearm pass through the narrow tunnel.

The median nerve passes through the carpal tunnel to receive sensations from the thumb, index, and middle fingers of the hand. Any condition that causes swelling or a change in position of the tissue within the carpal tunnel can squeeze and irritate the median nerve. Irritation of the median nerve in this manner causes tingling and numbness of the thumb, index, and the first three fingers. This irritation and its symptoms are the condition known as "carpal tunnel syndrome."

Anatomy similar to that of the wrist and hand exists in the ankle and foot. Tarsal is a word derived from the Latin word for ankle. When the sensory nerve that passes through the tarsal tunnel is irritated by pressure in the tunnel, numbness and tingling of the foot and toes can be felt. This condition is referred to as "tarsal tunnel syndrome." Tarsal tunnel syndrome is analogous to, but far less common, than carpal tunnel syndrome. It is treated similarly.

For most patients, the cause of their carpal tunnel syndrome is unknown. Any condition that exerts pressure on the median nerve at the wrist can cause carpal tunnel syndrome. Common conditions that lead to carpal tunnel syndrome can include obesity, pregnancy, hypothyroidism, arthritis, diabetes, trauma, and tendon inflammation.

Some rare diseases can cause deposition of abnormal substances in and around the carpal tunnel, leading to nerve irritation. These diseases include amyloidosis, sarcoidosis, multiple myeloma, and leukemia.

Note: Carpal tunnel syndrome may be a temporary condition that completely resolves or it can persist and progress.

As carpal tunnel syndrome progresses, patients can develop a burning sensation, and/or cramping and weakness of the hand. Decreased grip strength can lead to frequent dropping of objects from the hand. Additionally, sharp, shooting pains can sometimes be felt in the forearm. Chronic carpal tunnel syndrome can also lead to wasting (atrophy) of the hand muscles, particularly those in the palm of the hand near the base of the thumb.

The diagnosis of carpal tunnel syndrome is based on the symptoms and the distribution of hand numbness. The wrist can also be examined for swelling, warmth, tenderness, deformity, and discoloration.

The diagnosis is strongly suggested when a nerve conduction velocity (NCV) test is abnormal. This test involves measuring the rate of speed of electrical impulses as they travel down a nerve. With carpal tunnel syndrome, the impulse slows as it crosses through the carpal tunnel.

A test of muscles of the extremity, electromyogram (EMG), is sometimes performed to exclude or detect other conditions that might mimic carpal tunnel syndrome.

"Carpal tunnel release" is commonly an arthroscopic surgery that involves severing the band of tissue around the wrist to reduce pressure on the median nerve.

Most patients with carpal tunnel syndrome improve with conservative measures, including splinting, cortisone injection, and medications. Occasionally, chronic pressure on the median nerve can result in persistent numbness and weakness. In order to avoid serious and permanent nerve and muscle consequences of carpal tunnel syndrome, surgical treatment is considered.

After carpal tunnel release, patients often undergo exercise rehabilitation. Though it is uncommon, symptoms can recur.

Carpal tunnel syndrome typically affects the thumb, index, and middle fingers and is often particularly troublesome at night. Additionally, it affects almost 5% of the population and is most common in middle-aged women.

Despite the common belief that frequent typing can lead to carpal tunnel syndrome, the relationship between heavy typing and carpal tunnel syndrome is unclear. Actually, carpal tunnel syndrome is three times more common among assembly line workers than it is among data-entry personnel -- and frequent use of vibrating hand tools increases the risk of carpal tunnel syndrome.

A 2001 study found that even heavy computer use -- up to seven hours a day -- did not make people more likely to develop carpal tunnel syndrome.

While surgery may be required for severe cases of carpal tunnel syndrome, many cases can be handled at home. Home care for carpal tunnel syndrome is straightforward and can often provide relief for mild cases of carpal tunnel syndrome.

Many sufferers find relief by wearing a wrist splint, which can be purchased at most drugstores. The purpose of the splint is to keep the wrist in a neutral position at rest. Splinting is usually tried for a period of four to six weeks. Some people wear their splints at night only and others wear their splints both day and night, depending upon when the symptoms are at their worst.

If no relief is found at four to six weeks, the splints are not likely to help, and it's time to call a doctor.