Carpal Tunnel Syndrome, have you ever felt tingling and numbness in your hands and wrists while you were working? And you often try to ignore it, and then one day, suddenly there is a sharp tingling pain through your wrist and radiating to your arm? If so, you are probably suffering from carpal tunnel syndrome, commonly known as “mouse hand”! The cause of carpal tunnel syndrome is an increase in pressure in the carpal tunnel that causes compression of the median nerve. The carpal tunnel is a bony fibrous canal composed of the carpal bones and the supporting bands of the flexor muscles. The former forms the radial, ulnar, and dorsal walls of the carpal tunnel, while the latter forms the palmar wall. The carpal tunnel is topped by a flexor support band that spans between the ulnar side of the hook bone and the triangular bone and the radial side of the navicular and mostly angular bones. The median nerve and flexor tendons pass through the carpal tunnel (flexor digitorum longus tendon, four flexor superficial tendons, and four flexor digitorum profundus tendons). Although the carpal tunnel has open entrances and exits at both ends, the tissue fluid pressure within it is stable. The narrowest point within the carpal tunnel is approximately 50 px from the carpal tunnel rim, an anatomical feature consistent with the morphological presentation of the median nerve during incisional surgery in patients with carpal tunnel syndrome. The median nerve travels beneath and immediately below the flexor support band. Distal to the flexor support band, the median nerve gives off a return branch that innervates the short thumb flexor, the superficial head of the short thumb flexor, and the thumb to palmar muscle. Its terminal branch is the finger nerve, which innervates the radial half of the skin of the thumb, demonstrator, middle finger, and ring finger [2]. Either an increase in the contents of the carpal tunnel or a decrease in the volume of the carpal tunnel can lead to an increase in intracarpal tunnel pressure. The most common cause of increased intracarpal tunnel pressure is idiopathic peritendinous synovial hyperplasia and fibrosis within the carpal tunnel, the mechanism by which this occurs is not known. Other rare causes are sometimes seen, such as flexor muscle belly hypoplasia, inflammation of the synovial membrane such as rheumatoid, trauma or degeneration resulting in abnormal compression of bony structures within the carpal tunnel on nerves, and soft tissue masses within the carpal tunnel such as tendon sheath cysts. Some studies suggest that excessive use of the fingers, especially repetitive activities such as prolonged mouse use or typing, can cause carpal tunnel syndrome, but this view remains controversial. Carpal tunnel syndrome is also prone to occur in pregnant and lactating women, and the mechanism is unknown. Some suggest that it is related to tissue edema due to estrogenic changes, but many patients continue to have unrelieved symptoms after the end of pregnancy.