Abstract
Human skins collected from the inguinal regions were subjected to tension, and temporal changes on their surface were observed by the replica method and scanning electron microscopy. Structural changes in the skin were also observed by light microscopy. The mean tension per unit width was 0.774 kg/mm and the maximum extension rate was 83.5 % on average. On relaxed condition relatively linear principal sulci cross each other vertically or obliquely to form tetragonal or triangular fields. Narrow secondary sulci slightly shorter than prinicipal ones cross the latter in various directions to form small irregular fields. With the application of tension to the skin, the running pattern of these principal sulci change toward the direction of the tension, gradually resulting in parallel lines. The fields become flat or fusiform. The secondary sulci sharpen and clarify, making them difficult to differentiate from the principal ones. On microscopic observation the longitudinal surface shows disappearance of the sulci, fields and dermal papilla. Collagen fibers and elastic fibers of the dermis extend toward the direction of tension and arrange in a row. By contrast, the transectional surface shows clarification of the sulci and dermal papilla in quantity and size. The fiber groups of the dermis show beehive-like patterns. From these findings, the tension applied to the skin seems to induce extension of the fibers of the dermis, leading to deformation of the dermal papilla, and to manifest as changes in the skin surface as a result of the influence of the sulci on the site of adherence between the dermis and epidermis.
