Modelling the Triceps Surae Informed using Diffusion Weighted Imaging and 3D Ultrasound

Abstract

This thesis investigates the influence of muscle architecture on predicted mechanics. Specifically, we evaluate the influence of predicted continuum shape and strain in the Triceps Surae muscle of the rabbit and human. Muscle structure was derived using two imaging modalities, (i) Diffusion Weighted Imaging (DWI) for a rabbit; and (ii) 3D Ultrasound for human subjects. For the rabbit we present measured musculotendon forces during rigor mortis and propose a method for comparing stable post rigor behaviour with the post-mortem state. Novel aspects of this thesis include the development of a rabbit rig and force transducer designed to fit in an animal MRI, validation of fitted fibre errors using a celery phantom, the reporting of material properties useful in computational mechanics and the proposal of a muscle primitive useful for building finite element models of muscle. The overarching motivation for this thesis work was to understand how fibre architecture in muscles influences shape and mechanics, and how this information can best be used for animation purposes. The mechanics of muscle that is presented in this thesis can be used to inform lookup tables and statistical models for fast computation of muscle shape.