What Is Carpal Tunnel Syndrome (CTS)?
Carpal Tunnel Syndrome (CTS) is the name for a group of problems that includes swelling, pain, tingling, and loss of strength in your wrist and hand. It occurs when the median nerve, which runs from the forearm into the hand, becomes compressed or squeezed at the wrist. The carpal tunnel is a space in the wrist surrounded by wrist bones and by a rigid ligament that links the bones together. The median nerve runs through the carpal tunnel, a canal in the wrist that is formed by a series of small bones called the Metacarpals on three sides, and a fibrous sheath called the flexor retinaculum which acts as a pulley for the forearm flexors on the other. There are nine tendons of the hand that also pass through this canal. The median nerve can be compressed in one of a few ways, (1) be by swelling of the contents of the canal, (2) soft tissue swelling in and around the tunnel, (3) by direct pressure from part of a broken or dislocated bone. Nearly half of CTS sufferers have symptoms in both hands.
Anatomy of CTS
The top of the Carpal tunnel is formed by 8 carpal bones that form 2 rows and (scaphoid, lunate, triquetrum, pisiform) and the distal row of carpal bones (trapezium, trapezoid, capitate, hamate) create the top of the tunnel. These bones are small and glide against each other so that we can move our wrist in different directions. The other side of the carpal tunnel is formed by the flexor retinaculum which forms a retinacular bridge over the carpal tunnel. Its main function is to protect the contained tendon without a significant mechanical action in supporting the transverse carpal arch that acts as a pulley for the wrist flexor ligaments when tension is applied to them by contraction of the forearm flexor muscles.
Causes of Carpal Tunnel
Every time you type you are flexing and extending the wrist and fingers requiring the tendons that run inside the carpal tunnel to slide through their protective sheath. The sheath acts as a protective tube to separate the tendon from the surrounding tissues and prevent any adhesions from forming to the tendon itself. It is much like the hand break on a bicycle.
Researchers (2007) have concluded that when the carpal tunnel reaches a certain sustained pressure on wrist, injury is likely to occur. In order to keep pressure the risk zone, it is recommended that sustained wrist extension (bending the hand back) should not exceed 32.7 degrees, wrist flexion (bending the wrist toward the palm) should not exceed 48.6 degrees, ulnar deviation (sideways toward the small finger) should not exceed 14.5 degrees, and radial deviation (sideways toward the thumb) should not exceed 21.8 degrees.
Symptoms of carpal tunnel syndrome?
Typically, carpal tunnel syndrome begins slowly with feelings of burning, tingling, and numbness in the wrist and hand. The areas most affected are the thumb, index and middle fingers. At first, symptoms may happen more often at night. Many carpal tunnel syndrome sufferers do not make the connection between a daytime activity that might be causing the carpal tunnel syndrome and the delayed symptoms. Also, many people sleep with their wrist bent, which may cause more pain and symptoms at night. As carpal tunnel syndrome gets worse, the tingling may be felt during the daytime too, along with pain moving from the wrist to your arm or down to your fingers. Pain is usually felt more on the palm side of the hand.
Typically, carpal tunnel syndrome begins slowly with feelings of burning, tingling, and numbness in the wrist and hand. The areas most affected are the thumb, index and middle fingers. At first, symptoms may happen more often at night. Many carpal tunnel syndrome sufferers do not make the connection between a daytime activity that might be causing the carpal tunnel syndrome and the delayed symptoms. Also, many people sleep with their wrist bent, which may cause more pain and symptoms at night. As carpal tunnel syndrome gets worse, the tingling may be felt during the daytime too, along with pain moving from the wrist to your arm or down to your fingers. Pain is usually felt more on the palm side of the hand.
Category: Disorders, feature, Health Conditions, Science
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