Am J Chin Med. 1981 Winter; 9(4): 291-7.

Studies on the phenomenon of latent propagated sensation along the channels. II. Investigation on the lines of LPSC on the twelve main channels.

Yu SZ, Zhang M, An S, Yang SY, Zhang SY, Zhu ZX, He QN.

Applying an electric impulse at the Jing points and then tapping on the skin surface along the lines perpendicular to the channels, latent PSC of 12 channels was examined respectively on 200 patients at an acupuncture clinic. Of the cases examined, 68.5% were found to have positive latent PSC. No prominent difference was found among the 12 main channels. In patients with higher sensitivity of latent PSC and in those with marked PSC as well, the traces of latent PSC can be located simply by tapping (i.e. without electric impulsation at the Jing points), and the width of the sensitive lines is about 0.5 cm. Furthermore, in cases with marked PSC, the latent sensation lines were always found to be a continuation of the marked ones. These facts indicate that the latent PSC is a common meridian phenomenon in a large number of individuals.