Carpal Tunnel Syndrome -

Carpal tunnel syndrome is a common condition that causes pain, numbness, and tingling in the hand and arm. The condition occurs when one of the major nerves to the hand — the median nerve — is squeezed or compressed as it travels through the wrist.

Symptoms -

You may feel a burning, tingling, or itching numbness in the palm of your hand and thumb, or index and middle fingers.
You might first notice that your fingers "fall asleep" and become numb at night. That usually happens in the evening because of the relaxed position of your hand and while sleeping.
In the morning, you may wake up with numbness and tingling in your hands that may run all the way to your shoulder.

Causes -

Carpal tunnel syndrome is caused by pressure on the median nerve.
The median nerve runs from your forearm through a passageway in your wrist (carpal tunnel) to your hand. It provides sensation to the palm side of your thumb and fingers, except the little finger. It also provides nerve signals to move the muscles around the base of your thumb (motor function).
Anything that squeezes or irritates the median nerve in the carpal tunnel space may lead to carpal tunnel syndrome. A wrist fracture can narrow the carpal tunnel and irritate the nerve, as can the swelling and inflammation resulting from rheumatoid arthritis.
There is no single cause in many cases. It may be that a combination of risk factors contributes to the development of the condition.