An Interpretation of the Initial Low Stiffness Phase of the in Vivo Load Extension Relationship for Human Skin

Abstract

Human skin has a highly non-linear load/extension relationship. The initial low stiffness phase is extremely variable with both site and orientation and is essentially the limit of physiologically viable uni-axial extension. A better understanding of the mechanics of this initial phase is sought, in particular the role of lateral contraction, in order that a more rational basis of modelling, the surgically more typical multi-axial strain condition, might be achieved. It is concluded that lateral contraction is not a corequisite of the initial low stiffness extension, and that fibre straightening is the more plausible explanation of this initial low stiffness phase, and its accompanying observed fibre reorientation.