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(Redirected from
Carpel tunnel)
| Carpal tunnel |
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| Transverse section across the wrist and digits. (The median nerve is the yellow dot near the center. The carpal tunnel is not labeled, but the circular structure surrounding the median nerve is visible.) |
| Latin |
canalis carpi |
The human wrist contains a sheath of tough connective tissue (the flexor retinaculum) which envelops and protects several structures. The carpal tunnel is the space between this sheath (above) and the bones (below) making up the wrist and hand (carpal bones).
[edit] Contents
- Tendons of the following muscles (not the muscles themselves):
Some sources also include the flexor carpi radialis,[1] although it is more precise to state that it travels in the flexor retinaculum which covers the carpal tunnel, rather than running in the tunnel itself.
- Nerves:
- Median nerve between tendons of Flexor digitorum profundus and Flexor digitorum superficialis
[edit] Clinical significance
The term 'carpal tunnel' is also used quite commonly to refer to 'carpal tunnel syndrome,' which is a condition where the median nerve is compressed within the tunnel and causes pain and/or numbness of the wrist/hand. It is often believed, but never proven, to be the result of repetitive motion such as painting or typing. The idea that carpal tunnel syndrome can be diagnosed using 'pain' is widespread, but quite controversial. Pain is a sensation, and therefore is interpreted by the cortex of the brain that receives information from a sensory neuron that was first stimulated by a sensory receptor peripherally. The palmar cutaneous branch of the median nerve branches from the main trunk of the nerve prior to its entrance into the carpal tunnel. The palmar cutaneous branch provides sensation in the palm of the hand, but not the fingers/thumb. The sensory fibers that innervate the thumb, index, middle, and radial half of the ring finger pass through the carpal tunnel, along with motor fibers to the thenar musculature. The flexor retinaculum (or transverse carpal ligament) is what initiates and compresses the median nerve and distrupts nerve conduction. Individuals with "classic" symptoms of carpal tunnel syndrome have numbness/tingling and/or pain in the median nerve distribution, which includes the thumb, index, middle, and radial half of the ring finger, and possibly weakness in the thenar muscles. It has been shown to be associated with obesity, hypothyroidism, diabetes, pregnancy, family history, rheumatoid arthritis, and wrist shape. It can be associated with certain fractures of the forearm and wrist. Work relatedness is less than is currently thought by the lay public and by non-hand surgeons. Even work that has high force and high repetitions is only partially related to the development of carpal tunnel syndrome. Neutral wrist position has shown to decrease pressure on the median nerve. The carpal tunnel is important, because the median nerve can be compressed in cases such as the following:
[edit] See also
[edit] References
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