The carpal tunnel is created by the wrist bones on the bottom and a ligament over the top. The median nerve runs through the tunnel along with the flexor tendons to the wrist. Pressure within the tunnel can compromise the nerve and lead to carpal tunnel syndrome. The hallmark of carpal tunnel syndrome is numbness in the thumb, index and middle finger. Additional symptoms can include:
- Numbness that is worse at night
- Weakness in the thumb muscles of the hand (in severe cases)
The condition is more common in pregnant women, middle age women, and people with jobs that include daily repetitive hand motions. The condition is diagnosed by a physical exam, as well as a Nerve Conduction Study, an electrical study that measures the length of time that it takes for a signal to cross the carpal tunnel. A delay is indicative or carpal tunnel syndrome. Intitial treatment usually consists of conservative physical therapy, contrast baths, nerve-tendon gliding exercises and addressing other potential causes of nerve entrapment (cervical spine, thoracic outlet, pronator teres muscle of the forearm). If the symptoms persist, cortisone injections can be tried. If conservative measures fail, or there is evidence of nerve damage (such as weak thumb muscles or profound numbness), then the carpal tunnel can be released by surgically incising the ligament to give the nerve root more room.