Determination of the temperature distribution in skin using a finite element model

When applying noxious heat stimuli to human skin in the study of the pain system, one of the main problems is not to cause permanent damage. A better understanding of the temperature distribution and the propagation of heat, i.e. heat flux, in human skin is thus needed. In order to investigate these problems thoroughly, we have developed a 3-dimensional finite element model (FEM) 4-layer of human skin. The model is kept simple for better understanding of the boundary problems. The water content in each layer is used for determining the thermal properties. It is therefore not a homogenous structure. In this model the stratum corneum has been included with lower water content than in the epidermis. Simulations shows that the surface temperature reaches high levels whereas the temperature in the deeper structure is much lower. Thermal and optical constants found in the literature was applied. Heat propagation downwards and outwards from the source has been investigated to understand of the accumulation of energy in the boundary between two layers. Prediction of the heat flux at boundary between the epidermis and dermis shows that for repetitive stimulation there is a risk of exceeding the threshold temperature of 65 degrees Celsius for irreversible damage.