Carpal tunnel syndrome, also known as CTS, occurs when the median nerve (the nerve that runs from the forearm into the hand) becomes compressed at the wrist. The median nerve controls the sensation to the palm side of the hand, the thumb and the fingers (except the little finger). The median nerve also controls the impulses that allow the small muscles of the hand to move, controlling the movement of the fingers and thumb. The carpal tunnel is a fixed, slender passage of bones and ligaments at the base of the hand that houses tendons and the median nerve. Swelling of irritated tendons or ligaments can cause the narrow tunnel to tighten, which can compress the median nerve. The result of pressure on the median nerve may be weakness, pain, or numbness of the hand and wrist that radiates up the arm. Although these sensations can be caused by other issues, carpal tunnel syndrome is the most common cause of entrapment neuropathy in which the nerves are traumatized or pinched.
Carpal tunnel syndrome is typically caused by several factors that put pressure on the median nerve and tendons in the area of the carpal tunnel, rather than an issue with the median nerve, itself. There is likely a genetic predisposition in some people to develop carpal tunnel syndrome, as the disorder is more common in people with small wrists (and small carpal tunnels). Other contributors include an injury to the wrist area that causes inflammation; hypothyroidism; an overly active pituitary gland; rheumatoid arthritis; repeated use of vibrating hand tools; work stress; mechanical problems in the wrist joint; fluid retention associated with pregnancy or menopause; growth of a tumor or cyst in the carpal tunnel canal. There are also frequent cases in which no clear cause can be identified.
There is very little clinical data to prove a link between repetitive or forceful motion of the wrist and hand during work or leisure activities with the development of carpal tunnel syndrome. However, it is known that repetitive motions can result in repetitive motion disorders, such as bursitis and tendonitis. One such disorder is writer’s cramp, a condition in which a lack of fine motor skill coordination, ache, and pressure in the fingers, wrist, or forearm is brought on by repetitive activity. None of the symptoms associated with writer’s cramp are symptoms of carpal tunnel.
The symptoms of carpal tunnel syndrome typically begin slowly, with frequent tingling, burning, itching, or numbness in the palm and fingers, especially the thumb, forefinger, and middle finger. Some people suffering from carpal tunnel syndrome report their fingers feeling useless and swollen, even though there are no visible changes. Some people suffering from carpal tunnel syndrome may feel the need to “shake out” the hand and wrist when they wake up. As the symptoms progress, people may experience a tingling sensation during the day, and strength in the hand will begin to decrease. As the hand strength decreases, people may find it increasingly difficult to make a fist, perform manual tasks, or hold small objects. If untreated, the muscles at the base of the thumb may waste away, and it may become difficult for that person to tell the difference between the feel of hot and cold.
Early diagnosis and treatment are important to avoid permanent, irreversible damage to the median nerve. Therefore, it is critical to see a physician as soon as possible to avoid causing permanent nerve damage and loss of function of the affected hand and wrist.
