Comprised of eight separate bones called the carpals, the wrist acts a connector between the forearm and the hand. Running through this cluster of small, uniquely shaped bones are a series of tendons, strands of tough yet somewhat flexible tissue that connect muscles to bones, and ligaments, fibrous strings that link bones to different bones much like the hinges of a door connect to the vertical framed opening referred to as the door jam. The transverse carpal ligament holds the bones in position where the wrist and the palm of the hand meet on top of the space known as the carpal tunnel.
The carpal tunnel is a type of narrow compartment located between the wrist and palm that houses nine flexor tendons; these are responsible for giving the fingers the ability to curl or flex towards the hand. The median nerve also runs through this opening which gives the thumb, first two fingers and part of the third finger the ability to feel sensations. This nerve is also responsible for sending signals from the brain to move the thumb. Passing over the area of the carpal tunnel and acting as a type of hood that transforms the grooved channel into an enclosed passageway is the transverse carpal ligament.
The complicated setup of the wrist allows the hand to have a unique set of movements not found in any other area of the body. However, since the wrist and hand area lack the protective muscle bulk found in most other places of the body, it can easily sustain an injury. The transverse carpal ligament, also referred to as the "flexor retinaculum" or "anterior annular ligament," for example, is a superficial structure, meaning it lies close to the surface. This means that too much pressure on this area or repetitive actions can irritate or injure this ligament.
Irritation to the transverse carpal ligament can trigger inflammation in the form of swelling and tenderness or pain to protect the area and initiate the healing process. Commonly, when the transverse carpal ligament swells, it pushes down on the carpal tunnel compartment, which in turn may squeeze the flexor tendons and the median nerve. This condition is referred to as carpal tunnel syndrome. In addition to causing pain, the pressure may also inhibit the function of the wrist and hand.
Treatment for carpal tunnel consists of conservative methods such as anti-inflammatory medications, splinting and learning to do common activities differently. However, if the pain and movement dysfunction becomes chronic or longstanding, surgery is often recommended. A procedure known as carpal tunnel release, in which the transverse carpal ligament is cut, can aid in relieving the pressure causing the symptoms.