The carpal tunnel syndrome.

The carpal tunnel is a channel with fibroosseous walls leading from the deep flexor space of the forearm into the palm of the hand. Superficially it is bounded by the flexor retinaculum which stretches from the trapezium and scaphoid laterally to the pisiform and hamate medially. This tough sheet blends proximally with the deep fascia of the forearm and distally with the palmar aponeurosis. The floor and sloping sides of the tunnel consist of the capsules of the radio-carpal and inter-carpal joints and the periosteum of the carpus itself. The contents are the tendons of the fingers and thumb and the median nerve. Motor and sensory changes in the hand have long been known to result from lesions of the median nerve at the wrist and at other sites. However, only in the last ten years has compression of the nerve in the carpal tunnel been recognized as responsible for the common syndrome of acroparaesthesiae (McArdle, 1949; Kremer et al., I953). This term was first used by Schultze (I893) to describe paroxysmal nocturnal tingling in the hands of middle-aged women. It used generally to be held that such symptoms were either vascular in origin or were caused by nerve compression at the root of the neck. Some authors, notably Walshe (194.5, 1951, 1955), still hold this to be so, though the fact that the wrist is the site of trouble seems proven by tests of conduction time in the median nerve.