Biaxial tensile testing and constitutive modeling of human vocal fold lamina propria

The vocal fold lamina propria plays an important role in human voice production and control. The lamina propria is often divided into the superficial, intermediate, and deep layers, with each layer of distinct mechanical properties. This layer-wise distinction in mechanical properties is generally considered essential in producing different voice types. However, due to the small size and irregular shape, and difficulty of access, mechanical characterization of each layer is almost impossible in humans. Thus, it is desirable to develop a structural constitutive model that links underlying structural characteristics of the lamina propria to its mechanical properties so that the properties of each lamina propria layer can be predicted. In this study, we developed a structural constitutive model based on previous imaging findings. The model was shown to be able to explain recent biaxial tensile testing results of human lamina propria at different vocal fold elongation conditions.