Carpal tunnel syndrome is possibly the most common nerve disorder experienced today. The carpal tunnel is located at the wrist on the palm side of the hand just beneath the skin surface (palmar surface). Eight small wrist bones form three sides of the tunnel, giving rise to the name carpal tunnel. The remaining side of the tunnel, the palmar surface, is composed of soft tissues, consisting mainly of a ligament called the transverse carpal ligament. This ligament stretches over the top of the tunnel.
The median nerve and nine flexor tendons to the fingers pass through the carpal tunnel. Flexor tendons help flex or bend the fingers. When the median nerve in the wrist is squeezed (by swollen tissues, for example), it slows or blocks nerve impulses from travelling through the nerve. Because the median nerve provides muscle function and feeling in the hand, this causes symptoms ranging from mild occasional numbness to hand weakness, loss of feeling and loss of hand function.
Usually, carpal tunnel syndrome affects only one hand, but can affect both at the same time, causing symptoms in the thumb and the index, middle and ring fingers. In addition to numbness, patients with carpal tunnel syndrome may experience tingling, a pins and needle sensation or burning of the hand occasionally extending up to the forearm.
Frequently, symptoms appear in the morning after a person wakes up, but they can also happen during the night and interrupt their sleep. Symptoms can occur with certain activities such as driving, holding a book or other repetitive activity with the hands, especially activities that require a person to grasp something for long periods of time or bend their wrist. Activities that require use of the hands, such as buttoning a shirt, may become difficult, and carpal tunnel sufferers may drop things more easily. Individuals will often shake their hands trying to obtain relief and may feel that their hand is swollen when no swelling is present.
Because numbness and tingling may be mild and occur only periodically, many do not seek medical help. However, the disease can progress to more persistent numbness and burning. In some severe and chronic cases of carpal tunnel syndrome, loss of muscle mass occurs at the base of the thumb on the palm side of the hand. In these instances, especially when untreated, individuals can experience hand weakness, impaired use of the hand, and loss of sensation in their hand due to permanent nerve and muscle damage.