In some parts of the body, the nerves pass through the confined spaces and there may be severe clinging if the surrounding tissues are swollen. One of the important nerves that is particularly vulnerable to this kind of damage is the middle nerve that transmits the signals from the fingers to the brain and vice versa. On its way through the wrist, the nerve passes through the tunnel formed by bones of the wrist and the solid membrane on the lower side of the wrist that connects the bones. This passage – a carpal tunnel – is rigid; if, for some reason, tissues in it get swollen, they will press and clench the nerve. Pressure on the nerve causes painful condition known as carpal tunnel syndrome.
Carpal tunnel syndrome is a fairly common disorder, especially among middle-aged women. There is some evidence that a change in the balance of female sexual hormones can lead to fluid buildup, and thus to swelling in the wrists in menopause. This may also occur during pregnancy due to fluid retention.
Symptoms of carpal tunnel syndrome include tingling and periodical numbness of the hand, which is often associated with pain. The pain is generally stronger at night, and may be so strong that you awaken from deep sleep; the pain will be reduced somewhat if you lower your arm over the bed and if you shake it and/or rub it. If the condition is severe, it can lead to permanent numbness and weakness of the thumb and one or more fingers. The syndrome can hit one hand or both.
In some cases the discomfort disappears by itself. Your doctor may prescribe a diuretic to reduce fluid in swollen tissues; injection of a corticosteroid drug into the wrist can help against the inflammation. But if you feel strong and lasting pain, the best cure is surgery. The surgeon will release the clenched nerve by cutting the firm membrane and thereby giving the nerve more space. This is usually a very successful procedure that immediately relieves the problems, requires a very short stay in the hospital (a day or two), and leaves a barely visible scar on the inside of the wrist.