In the diagnosis of carpal tunnel syndrome, various techniques have been employed. But there still remains a group of patient, particularly those with minor, intermittent symptoms, who escape confirmation. the sensory innervation to the ring finger is generally shared by the digital branches of median and ulnar nerves. In 150 hand studies on 75 normal adults, all had a recordable response in ring finger uponstimulation of the median and ulnar nerves at wrist, 14cm proximal to the recording electrode. Also we applied this method to the 15 patients of carpal tunnel syndrome.

The results were as follows.

1) The mean sensory latencies of median and ulnar nerves in dominant had were 3.03±0.59 msec, 3.01±0.56 msec respectively, while the mean amplitudes were 56.11±14.05 ㎶ and 50.75±11.23 ㎶ respectively.

2) The mean latencies of median and ulnar nerves in non-dominant hand were 3.15±0.02 msec, 3.06±0.81 msec respectively, while the mean amplitudes were 55.46±6.41 ㎶ and 51.21±16.32 ㎶ respectively.

3) There was no significant difference in latencies of median and ulnar nerves between the dominant and non-dominant hands.

4) There was no significant difference in the latencies of median and ulnar nerves between young and old, both in dominant and non-dominant hands.

5) The difference in latencies of median and ulnar nerves was 0.3 msec or less(95%) in normal subjects and 1.21±0.48 msec in carpal tunnel syndrome.

6) Recording sensory conduction in ring finger seems valuable in the diagnosing of carpal tunnel syndrome, especially of minor and early phase.