‘Carpal’ is a medical term which refers to the wrist. A ‘syndrome’ is a combination of problems which doctors recognise as a particular disease or disorder. The ‘carpal tunnel’ lies in the wrist and the tendons which run down from the muscles in the forearm to move the fingers pass through it. It also contains an important nerve called the median nerve. This nerve controls some of the muscles which move the thumb.
It also carries information back to the brain about sensations you feel in your thumb and fingers – particularly the index, middle and (occasionally) the ring fingers. In carpal tunnel syndrome the median nerve gets squeezed – often because the tendons become swollen and overfill the tunnel – and this causes a variety of symptoms.
Research shows that women are far more likely to have carpal tunnel syndrome than men. Those experiencing this condition will experience pain or aching and tingling or numbness. The symptoms are usually worse in the thumb, index and middle fingers. If the individual is right-handed the right hand tends to be worse, similarly the left hand if the individual is left-handed. Thy symptoms are usually worse at night (when they may disturb sleep patterns), or in the morning when people wake up.
If the nerve is badly squeezed the problems may continue throughout the day. The hand may feel weak, or the fingers numb or both.
If the problem is severe the thumb, index and middle fingers may be insensitive (numb) to either a gentle touch or to a pin prick.
In most cases there is not an obvious cause. However, the median nerve within the carpal tunnel is very sensitive to pressure, and the syndrome can be caused by an accumulation of fat or fluid within the tunnel.
In order to confirm the diagnosis, doctors often perform a nerve conduction test. Small electrodes are placed on the skin just above the wrist to stimulate the median nerve. In someone with carpal tunnel syndrome there is a delay before the impulse arrives in the thumb muscles. This delay can be measured and will tell the doctor whether the nerve is badly or only slightly compressed.
Diuretics (water tablets) may help particularly if the person is suffering from fluid retention.
If symptoms persist despite wearing a night splint, some doctors may recommend a steroid injection.
Surgery may be needed if there are persistent symptoms of any of the following:
- Pins and needles
- Loss of feeling in the thumb, index and middle fingers
- Numbness and pain at night that prevents sleep
The operation is carried out to reduce the pressure on the median nerve but still may not solve all the symptoms. Prevention is better than cure. When doing repetitive work, take regular breaks, exercise your fingers and hands. Setting up the task or workstation so you do not have to do lots of harsh regular movements with a great deal of pressure.
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