The Carpal Tunnel is a passageway in which the nine flexor tendons, median nerve, arteries, and lymphatic vessels pass through in order to supply function and movement to the fingers and wrist.

The Carpal Tunnel is lined by the carpal bones on the posterior surface (backside) of the wrist, and the transverse carpal ligament is positioned on the anterior (front side) of the wrist. The size of the carpal tunnel is about the size of the index finger in diameter, and the flexor tendons, arteries and nerves are expected to glide past each other with ease within the carpal tunnel. But in such a small, confined space, there is little room for error. If the tendon size increases from inflammation or hypertrophy (growth), or if the carpal tunnel size decreases because the weak extensor muscles cannot withstand the tremendous pull from the flexor muscles, the carpal tunnel will narrow and impinge the structures within.

Once the carpal tunnel has narrowed, any form of repetitive or static flexion will cause friction of the flexor tendons against the carpal bones causing inflammation and irritation to the structures within the carpal tunnel. This domino effect causes the symptoms to continually increase until the pain and dysfunction of the hand becomes unbearable, often resulting in carpal tunnel syndrome or some other form of repetitive strain injury.

Of course, overuse in any uni-directional movement pattern can cause muscle imbalances throughout the entire upper extremity, affecting the fingers, hands, wrists, forearms, elbows, upper arms and shoulders, but these imbalances can be corrected. In order to provide immediate and long-term relief, it is suggested that implementing the FLEXTEND and/or FLEXTEND-AC training systems into any upper extremity prevention or rehabilitation program will correct these musculoskeletal disorders.