A Computational Approach for Simulating Muscle Morphologic Changes in Musculoskeletal Modeling

Digital data characterizing the geometry of anatomic structures (e.g., bones, muscles and tendons) are becoming readily available from Magnetic Resonance Imaging and Computerized Tomography technology. These data can be useful in forward simulations of limb dynamics to study the interaction between tissue morphology and limb dynamics, but only if computational tools are available to manipulate these data to simulate various structural changes. The objective of this project was to develop a computational approach to simulate physiological changes in muscle volume and limb cross-section. A previously reported method for calculating the area and area centroid location of complex shapes was combined with a newly derived algorithm that simulates muscle hypertrophy or atrophy. The new algorithm modifies the cross-sectional areas of specified muscles and the spatial orientation of other muscles, as appropriate, to simulate desired muscle volume changes. An approach of this type is needed to facilitate musculoskeletal modeling and computer simulations of movement designed to address questions related to the interactions between muscle morphology, limb inertial properties and limb dynamics.