The London Lumbar Spine Model
A musculoskeletal model of the lumbar back and pelvis is being developed in OpenSim (Delp et al., 2007). Bone geometry is segmented from MRI scans and muscle anatomy is adapted from the dataset published by Christophy et al.with the purpose purpose of estimating muscle and joint contact forces during daily living activities.
The model is composed of 9 rigid bodies (torso, 5 lumbar vertebras, pelvis and sacrum, left and right femurs) connected by 8 spherical joints (hips and lumbar joints). The model has 24 degrees of freedom and 234 Hill-type actuators representing 12 muscle groups. A study is currently underway to enhance muscle representation and activation patterns deduced by static optimisation. Intervertebral disc modelling with stiffness matrices is also under investigation.
It is hoped that this enhanced model of the lumbar spine will give a better estimation of muscle and joint reaction forces, and help getting the most accurate results out of the different finite element models that will be developed by the group.