Causes of carpal tunnel syndrome
The carpal tunnel is a channel on the wrist, more precisely between the ball of the little finger and the ball of the thumb. It is formed by the small carpal bones and on the outside by a firm connective tissue band. The tendons of the flexor muscles of the hand located in the forearm run in this channel and move towards the fingers.
A nerve – the median nerve – runs through its center. It is responsible for the sensitive supply of the thumb side of the palm, the thumb, the index finger and the middle finger, i.e. for conveying feelings such as the sense of touch and for transmitting this information to the brain. In addition, it supplies some muscles in the region described above with motor energy, i.e. it transmits movement orders from the brain to the muscles and thus ensures the formation of a fist and finger movement, for example.
If a swelling occurs in this narrow channel – whether caused by an injury, a fracture of the wrist, overstrain or also by pregnancy, which is dealt with below – it presses on the nerve. This pressure results in nerve compression, which means that the information which the nerve is supposed to convey, whether sensory or motor, is reduced or not transmitted at all. Thus, on the one hand there is a sensitive pressure pain, on the other hand there are sensory disturbances such as tingling in the fingers and movement disorders in the hand and fingers. One speaks then of a carpal tunnel syndrome. Prolonged existence can result in a weakening of the musculature.
Pregnancy
As already indicated, pregnancy can be the cause of carpal tunnel syndrome. During pregnancy, the body accumulates more water in the connective tissue, which causes swelling. Compression syndromes can occur anywhere in the body. However, carpal tunnel syndrome is the most common, as the bony and connective tissue tight boundary does not offer any space for tissue expansion. The symptoms are often particularly unpleasant at night, but carpal tunnel syndrome usually resolves itself a few weeks after delivery when the water balance in the tissue normalizes.
