- Carpal tunnel syndrome (CTS) is the collection of symptoms and signs associated with median neuropathy at the carpal tunnel. Most CTS is related to idiopathic compression of the median nerve as it travels through the wrist at the carpal tunnel (IMNCT). Idiopathic means that there is no other disease process contributing to pressure on the nerve. As with most structural issues, it occurs in both hands, and the strongest risk factor is genetics.