Applications of Finite Element Analysis to Model and Understand the Complexities of Muscle in Clinically Relevant Scenarios

Muscle is a complex tissue with a hierarchical structure that works together to perform optimized functions. Developing theoretical frameworks to understand the relationship between muscle structure and function is a targeted goal in biomechanics; however, the complexity of muscle tissue necessitates advanced modeling approaches. The finite element (FE) method has provided new opportunities to explore questions regarding the form and function of muscle with regards to clinical applications. In this dissertation, I developed and applied novel approaches for creating, simulating, and analyzing finite-element models of muscle to explore the implications of three relevant areas. First, I created a model of volumetric muscle loss in the rat tibialis anterior to understand the complex relationship between injury size/location/shape influences muscle force. Second, I constructed a constitutive model of muscle mechanics that implements the force-velocity behavior as an open-source plugin for free FE software, in order to investigate how the force-velocity behavior influences muscle tissue strain distributions. Third, I develop a new model of soft palate closure that incorporated, for the first time, how activation of the superior constrictor muscle influences velopharyngeal function. This model was validated with MRI participant data, successfully predicted the outcomes of MRI-measured phonation, and provided new hypotheses how muscle function relates to common closure patterns. Taken together, these advances in the FE modeling of muscle provided a broad range of insight into muscle behavior and pave the way for future developments and tools to be harnessed for clinical applications.