The existing biomechanical models of the lumbo-sacral spine do not explain the role of the dorsal extensor muscle and fascia. The study attempts to explain the action of paraspinal muscles based on the mechanism of contraction and “hydro skeleton”. It was assumed that the muscle contracting produces hydrostatic pressure and in this way is able to resist and transfer loads. In this mechanism, inside ventricular pressure can modify the load transfer through the spine.
To confirm the hypothesis discussed above, a simplified simulation model of the lumbar spine was built. For this purpose, scientific software named ABAQUS, using finite element methods was used. The model of the spine was mainly a kinematic model aimed at reflecting the impact of the work of the spinal muscle on the lumbar lordosis.