Carpal tunnel syndrome is a common condition caused by compression, or entrapment, of the motor and sensory nerve in the wrist (median nerve), resulting in pain, muscle weakness, impaired reflexes, numbness, and tingling in the hand. Nerve compression is often associated with repetitive activities (e.g., typing, painting, hammering) that cause stress injury, swelling, and inflammation.

The carpal tunnel is a canal in the wrist through which fibrous connective tissue (tendons), nerves, and blood vessels pass. The transverse carpal ligament covers the carpal tunnel.

cause carpal tunnel syndrome include:

Conditions or illnesses that can cause or contribute to arm pain or swelling in the joints and soft tissues in the arm, or to reduced blood flow to the hands. These conditions and illnesses include obesity, rheumatoid arthritis, gout, diabetes, lupus, or hypothyroidism.

Repeated hand and wrist movements that cause the membranes surrounding the tendons (tendon sheaths) to swell (tenosynovitis).

The wrist is bounded on three sides by bones. The fourth side, the same side as the palm, has a thin covering across it, under which the structures lie that pass into the hand. The wrist bones are called the carpal bones, and this space is called the carpal tunnel.

Space in the carpal tunnel is limited. If anything leads to some of the space being taken up, this causes pressure to build up. The main contents of the carpal tunnel are the tendons which cause the hand to flex, but the structure in the wrist that is most sensitive to pressure is the nerve which passes into the hand (the median nerve).

Women are three times more likely to have carpal tunnel syndromethan men. Although there is limited research on why this is the case, scientists have several ideas. It may be that the wrist bones are naturally smaller in most women, creating a tighter space through which the nerves and tendons must pass. Other researchers are looking at genetic links that make it more likely for women to have musculoskeletal injuries such as CTS.

The main cause of the Carpal Tunnel Syndrome is the incorrect posture, especially in computer users and people working on other type of keyboard (Ergonomic Keyboard). The rolling of the shoulders forward, rounding the lower back and thrusting the chin forward, shortens the neck and the muscles of the shoulder, there by compressing the nerves in the neck which ultimately have an effect on the wrist, fingers and the hand. But it is difficult to know the relation between the repetitive wrist, wrist and the Carpal Tunnel Syndrome.

Bone or arthritic conditions of the wrist such as rheumatoid arthritis or wrist fractures may lead to carpal tunnel syndrome.

Various other conditions are associated with carpal tunnel syndrome. For example: pregnancy, obesity, an underactive thyroid, diabetes, the menopause, other rare medical illnesses, and a side-effect of some drugs. Some of these conditions cause water retention (oedema) which may affect the wrist and cause carpal tunnel syndrome.

The carpal tunnel is the space between this and the bones on the outside of the wrist. The tendons, the muscles of the fingers, blood vessels, and nerves pass through it. The median nerve lies on top of them on the inside of the wrist. There is just enough room for it between the tendons and the transverse ligament.

Most cases of CTS are idiopathic: without a known cause.[5] A common factor in developing carpal tunnel symptoms is increased hand use or activity. While repetitive activities are often blamed for the development of CTS, the correlation is often unclear. Physiology and family history may have a significant role in individual's susceptibility. Furthermore, stress, trauma and several other diseases are also possible causes of CTS.