Sensory conduction study of distal radial nerve.

The technique of recording superficial radial sensory nerve action potential (SNAP) from the thumb was compared with that of recording from the 1st web space. The spread of stimulus to the median nerve in the forearm when stimulating the radial sensory nerve with relatively high intensity was also investigated. Recording the radial SNAP from the 1st web space produces a larger amplitude response with a sharper takeoff point compared with that of recording from the thumb. Furthermore, with the former technique, the radial SNAP is uncontaminated by a component arising in the median distribution which makes interpretation of its configuration more reliable.