Mechanical Behaviour of Skin: A Review

Objective: The mechanical behaviour or the Young’s Modulus of the skin is measured as a ratio of the stress applied to the skin in vitro or in vivo over the skin deformation. The Young’s Modulus of skin is an important factor to estimate the characteristics of skin, to determine the course of a disease or to follow a cosmetic application. Methods: The mechanical behaviour of the skin is measured by changing the shape of skin by employing tensile, indentation, and suction and torsion tests. Results: Out of all the skin’s mechanical testing methods, suction tests are a common choice for skin testing, as they are easy to apply in vivo and consider both in-plane and normal loading conditions. Skin is found to be highly anisotropic and viscoelastic, with a range of Young’s Modulus between 5 kPa and 140 MPa. Conclusion: This paper reviews in vivo and in vitro reported values for Young’s Modulus of human skin for tensile, indentation, suction and torsion mechanical testing methods.