Skin and skin simulants

There is an interest within forensic science to understand the physical and mechanical properties of human skin and the natural and synthetic simulants used to represent it, particularly with reference to reconstruction studies that consider injury to humans, for example during sharp-weapon and ballistic impact assaults. This paper discusses literature in the broad area of (i) human skin, (ii) animal skin and products such as leather and (iii) synthetic polymeric skin simulants. The physical and mechanical properties of human skin appear to be reasonably well documented in the literature. Animal models discussed appear to be restricted primarily to pig and to a lesser extent goat, plus some data on different types of leather. All skin (human and animal) and derivatives such as leather (from various animal sources) are natural materials and therefore variable in their physical and mechanical properties. The variability of commonly used simulants for human skin such as various types of leather could impact on the confidence of any reconstruction study data obtained by using such simulants. While it is recognized that synthetic simulants (polymers such as silicone and polyurethane) do not have the structure of human skin, their physical and mechanical properties can be manipulated relatively easily to match those of skin and are typically of low variability, providing confidence in the repeatability and reproducibility of reconstruction studies.