A Basic Explanation of Carpal Tunnel Syndrome




On this Page: What happens? A common test How does it happen? What can be done? Common Terms




What Happens?

Fatigue, Pain, Tingling, Weakness of Grip, Loss of Dexterity, Stiffness, Cramping, Numbness, Cold, Burning. They may often occur during or after periods of rest or sleep. In advanced cases, you may feel pain or cramping around the base of the thumb or your thumb may become nonfunctional.
These symptoms often characterize the common disorder. By the time you feel any of them in your hand, wrist or arm, cell degeneration is in process and should be taken seriously. It often progresses rapidly if ignored and doesn't take years to develop as many think. Often, just a few mild instances suddenly never go away or are brought on by ever decreasing effort.

A common test for CTS is Phalen's Maneuver. Put the backs of your hands together while keeping your arms parallel to the floor and your fingers pointing down. Hold your hands together firmly. If within a minute, you experience one, or a combination, of the symptoms, you probably have the disorder. Don't hold this position for more than a minute or after any symptoms occur.



How Does It Happen?

As shown, the Carpal Tunnel (pink area) is made up of several bones (white) connected by ligaments. The largest of which is the Transverse Carpal Ligament (blue). These structures form the perimeter of a passage through its center called the carpal tunnel (also called the carpal canal). Through this tunnel run nerves, tendons, blood and other soft tissues. For a variety of reasons some of these soft tissues swell, especially the tendons (red) and the protective sheaths that cover them. Overuse (Repetitive Strain Injury or RSI), injuries such as sprains, friction between the tendons and their protective sheaths, fractures, fluid retention, forceful movements and infection are a few of the more common causes. However, unlike most of your body where swelling simply protrudes, this swelling has no place to expand since it is encircled by bones and ligaments. Consequently, because the swelling is contained, pressure builds in the tunnel. This pressure then crushes the main nerve to your hand called the Median Nerve (yellow), causing it not to function properly. The pressure also obstructs blood flow which retards healing and causes further cell degeneration until the cycle spirals out of control. The results are the symptoms listed above and most victims are amazed by the swiftness mild symptoms can progress into a major problem. For more information, click here for the NIOSH CTS page or here for our "What is CTS and RSI?" page.

What Can Be Done?

The most common first aid is to treat the cause of the swelling with drugs. By trying to reduce the swelling, the pressure is decreased and if the median nerve is not damaged, it's function can be restored. However, many times the tissues are so enlarged that drugs can't reduce their size. Another approach is to use braces. Braces keep the hand in a position that prevents the wearer from causing even more damage due to bending or twisting at the wrist with the hopes that the pressure will subside in time. Braces are often used in conjunction with drug therapies. In addition, changing the way you use your hands can be beneficial. See our Ergonomic Tips page for suggestions. Just minor changes such as lowering your keyboard height can significantly raise the threshold of effort needed to make the symptoms arise. For more information regarding proper work area layout, click here.

In very advanced cases, a procedure called a Carpal Tunnel Release Operation is performed. It involves cutting the Transverse Carpal Ligament and letting it heal back together. This gives more room for the soft tissues and therefore lowers the pressure. Surgery is expensive, usually requires many weeks to recover, and is far from being a guaranteed cure. However, there is another approach. Even though the transverse carpal ligament doesn't automatically stretch to accommodate swelling, it can be stretched externally. This technique can be used a preventative method, as well as, a way to help relieve symptoms before they spiral out of control. Visit our Home Page for how this is done.

Glossary of Terms

Median Nerve
a major nerve to the hand that controls the thumb, index and middle fingers
Carpal Tunnel
a passage in the wrist through which the median nerve and tendons travel to the hand, much of it located at the base of the palm
Transverse Carpal Ligament
a tough but elastic structure which holds the bones of the Carpal Tunnel together, often surgically cut to relieve pressure on the median nerve
Repetitive Strain Injuries (RSI), Cumulative Trauma Disorder (CTD), Repetitive Motion Syndrome (RMS), Occupational Overuse Syndrome (OOS)
synonymous terms for disorders caused by prolonged, repetitious tasks
Carpal Tunnel Syndrome (CTS)
pressure (or compression) on the median nerve that may cause pain, numbness, weakness, etc.
Tendonitis
inflammation of a tendon, the structures that link muscles to bones
Tenosynovitis
inflammation of a tendon's sheath which causes it to swell and may also retard proper lubrication of the tendon inducing more injury
Carpal Canal
sometimes used interchangeably with Carpal Tunnel
Ulnar Nerve
another main nerve to the hand which controls the last two fingers, it passes outside the carpal tunnel but can be affected by tennis elbow or displacement


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