Development of an articulated lumbar and thoracic spine model
suitable for kinematic analysis. The model uses the lumbar model by Christophy et al
as a base, but has added custom joints to the thoracic spine segments. Christophy’s model has been modified in the following way:

- Separated the thoracic vertebrae in the torso as separate bodies and added custom
inter-vertebral joints.
- Applied ROM constraints for each inter-vertebral joint using a meta-analysis of
data from the literature.
- Positioned the joints using the Instantaneous Axis of Rotation (IAR) from the
literature.
- Replaced the pelvis weld joint to the ground with a custom joint that allows
translation in 3D space.
- Removed bodies that are not required for our study (e.g. Rib Cage).
- Added model markers on key bony landmarks such as the pelvis and spinous
processes for scaling and IK purposes.