A Simple Model of Changes in Lumbar Intervertebral Angles During Sagittal Torso

Objective: To create simple models of intervertebral angle that account for subject anthropometry and are simple to apply within biomechanical models. Background: Biomechanical models require accurate intervertebral angle data if they are to correctly partition calculated forces into compression and shear. Current intervertebral angle models either require extensive instrumentation or were developed using limited subject populations. Methods: MRI images were collected from 13 males and 13 females in a series of sagittally flexed postures. Measured intervertebral angles and anthropometry were used to create linear regression equations of the L5/S1 through T12/L1 motion segments. Results: The models are predictive of posture related intervertebral angle changes. Conclusions: Models of intervertebral angle developed here require simple measures that allow accurate prediction of changes in intervertebral angles that can be used in biomechanical models for predicting forces acting on the lumbar spine