The Carpal Tunnel is the anatomical name given to the space between the anterior surface of the carpal (wrist) bones and a sheet of connective tissue called the flexor retinaculum that overlays them. As well as containing the very long tendons of the wrist flexor muscles, the carpal tunnel also contains the median nerve.
This is caused by pressure on the median nerve as it passes through this area of the wrist. It is an example of an entrapment disorder, where a nerve runs in a restricted space and is liable to compression from neighbouring structures. In the case of carpal tunnel syndrome, this can result from continuous repetitive movements of hand, for example from the use of keyboards. There is uncertainty about the exact causes but thickening in the synovial sheaths of the flexor tendons or arthritic changes in carpal bones are thought likely to be involved.
This is common in patients with rheumatoid arthritis, hypothyroidism, in pregnancy, and during the menopause.
Symptoms of Carpal Tunnel Syndrome
The symptoms of carpal tunnel syndrome include pins & needles, numbness, and pain affecting the hand (but not the little finger or half of the ring finger, which are supplied by another nerve). There may also be weakness of the thumb due to wasting of the muscles in the thenar eminence (the mound of tissue at the base of the thumb), a burning sensation, pain radiating up the arm, and weakness when gripping. The symptoms of carpal tunnel syndrome tend to be worse at night. It can lead to permanent nerve and muscle tissue damage.
Acupuncture for carpal tunnel syndrome usually involves working on the hand and the wrist but also working further up the arm and sometimes even the shoulder, either with acupuncture or a form of massage.
There is also a good success rate for surgery for this condition, which involves decompression of the carpal tunnel by making a longitudinal incision through the flexor retinaculum.