The present study investigates the layer-specific mechanical behavior of human skin. Motivated by skin’s histology, a biphasic model is proposed which differentiates between epidermis, papillary and reticular dermis, and hypodermis. Inverse analysis of ex vivo tensile and in vivo suction experiments yields mechanical parameters for each layer and predicts a stiff reticular dermis and successively softer papillary dermis, epidermis and hypodermis. Layer-specific analysis of simulations underlines the dominating role of the reticular dermis in tensile loading. Furthermore, it shows that the observed out-of-plane deflection in ex vivo tensile tests is a direct consequence of the layered structure of skin. In in vivo suction experiments, the softer upper layers strongly influence the mechanical response, whose dissipative part is determined by interstitial fluid redistribution within the tissue. Magnetic resonance imaging-based visualization of skin deformation in suction experiments confirms the deformation pattern predicted by the multilayer model, showing a consistent decrease in dermal thickness for large probe opening diameters.

本研究调查了人体皮肤的特定层机械行为。受皮肤组织学的启发，提出了一种区分表皮、乳头状和网状真皮以及皮下组织的双相模型。离体拉伸和体内抽吸实验的逆向分析产生每一层的机械参数，并预测硬网状真皮和依次较软的乳头状真皮、表皮和皮下组织。模拟的特定层分析强调了网状真皮在拉伸载荷中的主导作用。此外，它表明在体外拉伸试验中观察到的平面外偏转是皮肤分层结构的直接结果。在体内抽吸实验中，较软的上层强烈影响机械响应，其耗散部分由组织内的间质液重新分布决定。抽吸实验中基于磁共振成像的皮肤变形可视化证实了多层模型预测的变形模式，显示大探头开口直径的真皮厚度一致减少。