体表の不動点を利用した皮膚変形量の測定法の一試案

The present study was made to search for the origin on human dorsal surface, whlch is available for a correct grasp of a change of body surface (skin surface) with human activities and to try to re-evaluate, using the above origin, quantitative skin daformation of human dorsal surface on raising arms. The following results were obtained : l) X. examination in standing (static) and arm-raising (dynamic) positions revealed a site with inter-positional difference, as zero, in slippage on dorsal median line. This site was supposed to be the origin and was confirmed to be Th_10 and Th_12. The palpation of the site of, Th_10 and Th_12 on dorsal medlan line was thought to be simple and effective in searching for a site with the least bone and skin slippage, thus in presuming the origin. 2) Based upon the origins on dorsal median line and scapular line parallel thereto in sitting position, 5 cm φ-correct circles were stamped up and down, then arm raising action was taken. The utilization of the origin enabled us to determine the length, l , directional angle, θ, and area, S, of the slippage between correct and distorted circles as obtained by these actions. 3) For arm raising, the skin slipped up and down on median line for lower and higher sites than the origin, respectively, with the angle θ on scapular line indicating the + direction, while l and θ appeared greater and smaller for a nearer site to the origin, respectively. 4) S showed a tendency to have greater and smaller changes at lower and higher sites on median line than the origin, respectively, while on scapular line, the areal change generally appeared greater than that on median line, having a tendency to be greatest at a near site to the origin, with a decrease according to a lower site than the origin Besides S and S' as obtained in an origin-free condition proved to be SS'. Therefore, the involvement of the origin in the grasp of the skin change on human dorsal surfac e was confirmed.