Since first being reported in the early 20th century, carpal tunnel syndrome (CTS) has become the most common nerve compression problem in this country today, affecting one percent of the population. It is not surprising then that it is the most common ailment reported to workers' compensation carriers. While diagnosis, pathology, and treatment have become more firmly established, the search for the cause of this problem continues to evolve.

A primer on the anatomy of the carpal tunnel will help provide an understanding of the reason for the complaints from a patient with this syndrome. The median nerve travels from the wrist into the hand through the carpal canal, which is basically a tunnel with a bony floor and walls and a very strong ligament as its ceiling. In addition to the nerve, the thumb tendons and eight finger tendons fit through the same tight passageway. There is very little room for play or stretching in this canal; therefore, anything that causes swelling in the tendons or decreases the space in the canal will push the median nerve against the ligament and compress the soft nerve. As a result, nerve signals cannot get through the nerve, leading to the loss of sensation and function. It is analogous to parking your car on the garden hose while watering the garden. The hose will function, but you won't water much of anything until you move the car off the hose. Something must be done to relieve the pressure on the nerve so that the nerve can once again transmit the sense of touch, heat, cold, and other sensations.

Patients with CTS typically complain of numbness and tingling at night, while driving, working, or doing repetitive activities. Diagnosis is generally made by history, physical, and exam testing. There are other causes for numbness and these often can be differentiated with electrical studies. EMG and nerve conduction studies can help separate hand problems from neck compression and can often detect other problems, such as diabetic nerve damage.