In order to provide korean standard latency value of SEP stimulating each sensory dermatome, dermatomal SEP studies representing C5 to C8 roots were done on 30 healthy normal volunteers.

The average short latency values of N20 potentials were calculated, and the effect of arm length and height on the short latencies were also calculated. The mean latencies from C5, C6, C7 and C8 were 15.25±2.35 msec, 2054±2.36 msec, 20.86±2.14 msec, and 20.82±2.46 msec, respectively, without any significant difference between two sides. The latencies were significantly prolonged in male subjects compared to females, and they were highly correlated with arm length and height.