MEDIAN NEURITIS resulting from compression in the carpal tunnel may occur in a variety of otherwise unrelated illnesses. Frequently, no specific primary cause is found, although any disease or condition that increases the contents in the carpal canal may result in compression of the nerve against the transverse carpal ligament. Thus, tenosynovitis or edema of the tenosynovium from any cause, may produce secondary compression of the nerve. The symptom complex resulting from this compression, commonly known as the carpal tunnel syndrome, consists of unilateral or bilateral episodic paresthesias, involving part or all of the distribution of the median nerve in the hand. These are intensified several hours after retirement, and nocturnal pain is a feature. The pain may awaken the patient from sleep, and often is relieved by shaking the extremity or maintaining it in a dependent position. Symptoms decrease with morning activities, although they may be aggravated by overexertion.