The carpal tunnel is located between the two flexion creases of the wrist. It lies between the wrist bones underneath and a ligament (the flexor retinaculum) above. The flexor tendons of the hand and the median nerve responsible for thumb, index and middle finger sensitivity and strength, pass through this canal. Carpal tunnel syndrome corresponds to compression of the median nerve.
For reasons related to injury (following a fracture), hormones (hormonal changes: menopause, pregnancy) or mechanical factors (repeated movements), the internal pressure in the carpal tunnel increases. The median nerve then becomes compressed. The first three fingers become numb, and tingling then develops, followed by pain (often at night). Carpal tunnel syndrome is what is known as a repetitive strain injury. It is common and usually affects women over the age of 50.
Many cases of carpal tunnel syndrome disappear on their own after 2 years. During this period, resting the wrist at night by wearing a rigid splint produces good results in 70% of cases: prevention of flexion of the wrist and balancing of the muscles reduces internal pressure in the carpal tunnel. Tingling is eliminated and pain is reduced, both at night and during the day.
If orthopaedic treatment fails, or in the event of post-traumatic damage or micro-traumas due to repeated movements, surgical treatment is recommended. If carpal tunnel syndrome is not managed, paraesthesia (tingling, burning sensations) will be accompanied by paresis (reduced thumb pincer strength) and may even progress to paralysis: impossible to write or hold an everyday object, such as a knife or fork. In all cases, do not hesitate to talk to your doctor about the problem.
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