Carpal tunnel syndrome is pressure on the median nerve -- the nerve in the wrist that supplies feeling and movement to parts of the hand. It can lead to numbness, tingling, weakness, or muscle damage in the hand and fingers.
Causes, incidence, and risk factors
The median nerve provides feeling and movement to the "thumb side" of the hand (the palm, thumb, index finger, middle finger, and thumb side of the ring finger).
The area in your wrist where the nerve enters the hand is called the carpal tunnel. This tunnel is normally narrow, so any swelling can pinch the nerve and cause pain, numbness, tingling or weakness. This is called carpal tunnel syndrome.
Carpal tunnel syndrome is common in people who perform repetitive motions of the hand and wrist. Typing on a computer keyboard is probably the most common cause of carpal tunnel. Other causes include:
- Sewing
- Driving
- Assembly line work
- Painting
- Writing
- Use of tools (especially hand tools or tools that vibrate)
- Sports such as racquetball or handball
- Playing some musical instruments
The condition occurs most often in people 30 to 60 years old, and is more common in women than men.
A number of medical problems are associated with carpal tunnel syndrome, including:
- Bone fractures and arthritis of the wrist
- Acromegaly
- Diabetes
- Alcoholism
- Hypothyroidism
- Kidney failure and dialysis
- Menopause, premenstrual syndrome (PMS), and pregnancy
- Infections
- Obesity
- Rheumatoid arthritis, systemic lupus erythematosus (SLE), and scleroderma
Symptoms
- Numbness or tingling in the thumb and next two or three fingers of one or both hands
- Numbness or tingling of the palm of the hand
- Pain extending to the elbow
- Pain in wrist or hand in one or both hands
- Problems with fine finger movements (coordination) in one or both hands
- Wasting away of the muscle under the thumb (in advanced or long-term cases)
- Weak grip or difficulty carrying bags (a common complaint)
- Weakness in one or both hands
Expectations (prognosis)
Symptoms often improve with treatment, but more than 50% of cases eventually require surgery. Surgery is often successful, but full healing can take months.
Complications
If the condition is treated properly, there are usually no complications. If untreated, the nerve can be damaged, causing permanent weakness, numbness, and tingling.
Prevention
Avoid or reduce the number of repetitive wrist movements whenever possible. Use tools and equipment that are properly designed to reduce the risk of wrist injury.
Ergonomic aids, such as split keyboards, keyboard trays, typing pads, and wrist braces, may be used to improve wrist posture during typing. Take frequent breaks when typing and always stop if there is tingling or pain.
