Patient-specific fibre-based models of muscle wrapping

Abstract

One contribution of 25 to a Theme Issue 'The virtual physiological human: integrative approaches to computational biomedicine'. In many biomechanical problems, the availability of a suitable model for the wrapping of muscles when undergoing movement is essential for the estimation of forces produced on and by the body during motion. This is an important factor in the Osteoporotic Virtual Physiological Human project which is investigating the likelihood of fracture for osteoporotic patients undertaking a variety of movements. The weakening of their skeletons makes them particularly vulnerable to bone fracture caused by excessive loading being placed on the bones, even in simple everyday tasks. This paper provides an overview of a novel volumetric model that describes muscle wrapping around bones and other muscles during movement, and which includes a consideration of how the orientations of the muscle fibres change during the motion. The method can calculate the form of wrapping of a muscle of medium size and visualize the outcome within tenths of seconds on commodity hardware, while conserving muscle volume. This makes the method suitable not only for educational biomedical software, but also for clinical applications used to identify weak muscles that should be strengthened during rehabilitation or to identify bone stresses in order to estimate the risk of fractures.

Muscle Synergy Constraints Do Not Improve Estimates of Muscle Activity From Static Optimization During Gait for Unimpaired Children or Children With Cerebral Palsy

“…To address this, previous studies examining synergies in musculoskeletal modeling that use EMG shape tracking tune musculotendon properties as part of the model calibration (Walter et al, 2014;Meyer et al, 2016;Serrancolí et al, 2016), but these parameters are difficult to validate. Other musculoskeletal studies incorporate imaging data to personalize bone and muscle geometry (Barber et al, 2011;Scheys et al, 2011;Kohout et al, 2013;Handsfield et al, 2016;Modenese et al, 2016;Sartori et al, 2017). Incorporation of subject-specific geometry and muscle properties may influence the utility of synergies in modeling muscle activations, but the degree of personalization required remains unclear.…”

Mechanics of Psoas Tendon Snapping. A Virtual Population Study

“…Probably the most important property of this approximate method is speed of calculation, allowing for real time visualization of tendon-muscle paths during motion. In addition, these predictions can be used as "seeding" position for more complex volumetric wrapping techniques (Kohout et al, 2013) or full 3D finite element (FE) models of muscle (Reynolds et al, 2004;Blemker and Delp, 2005). In parallel with this evolution, research has focused on more anatomical descriptions of the 3D geometry of adjacent bony and soft tissue structures as limiting constraints, adding to the complexity of an already challenging problem (Gao et al, 2002;Marai et al, 2004;Desailly et al, 2010;Liu et al, 2012;Kohout et al, 2013;Hammer et al, 2019).…”

Real‐Time Modelling of Fibrous Muscle

“…Our muscle decomposition method was designed to be a part of our virtual human body framework [KCZ*13], depicted in Figure , that works with a musculoskeletal data model in which bones and muscles are represented by triangulated surface meshes in the rest‐pose position (as captured, e.g. from MRI images).…”

“…The model is fused with motion data defining the kinematics of the skeleton during various physical activities, e.g. walking or stair climbing, acquired from tracking markers placed on the subject (see [KCZ*13] for details). This provides the environment for the muscle deformation calculations to take place.…”