The carpal tunnel refers to the following wrist part: from the fibrous band to the wrist bone. Through the carpal tunnel, the median nerve can receive finger sensations.
If the wrist fibrous tissue has irritation or swelling, the median nerve is often affected, causing finger numbness or tingling. The thumb, the index finger or the middle finger may not properly response to the median nerve. This condition is often known as the carpal tunnel syndrome.
The following factors often lead to carpal tunnel syndrome: arthritis, diabetes, hand injury, obesity and hypothyroidism. Another risk factor is repetitive work involving wrist and fingers, e.g. keyboard typing or computer-related work.