Carpal Tunnels Syndrome (CTS) was first described by Sir James Paget in 1863, is the most common type of nerve injury. It results from compression of the median nerve (the nerve that supplies some of the muscles of the hand and also sensation to the palmar side of the thumb, first two fingers, and half of the fourth finger) in the carpal tunnel. The carpal tunnel is an enclosed ring formed by the transverse carpal ligament. This ring acts as a gateway from the forearm to the hand, through which pass not only the median nerve but also many of the tendons that connect the forearm muscle to the fingers they flex.
What is the causes carpal tunnels syndrome?

Conditions or illnesses that can cause swelling in the joints and soft tissues in the arm, or to reduced blood flow to the hands.
These include obesity, rheumatoid arthritis, gout, diabetes, lupus, and hypothyroidism.
Repeated hand and wrist movements. They can cause the membranes surrounding the tendons to swell (tenosynovitis).
Broken wrist bones, dislocated bones, new bone growth from healing bones, or bone spurs. These can take up space in the carpal tunnel and put more pressure on the median nerve.
Carpal tunnel syndrome is a common work-related condition. It can be caused by work that requires:
Forceful or repetitive hand movements.
Hand-arm vibration.
Working for long periods in the same or awkward positions.