| Spine disorders are one of the most prevalent and costly problems facing modern medicine, with an estimated annual cost of over ;Therefore, three principal aims are pursued in this work. The purpose of the first aim was to investigate the biomechanical performance of the human cadaver spine by applying a pure bending moment in conjunction with a range of compressive axial loads. This study showed that a minimum of 500 N compressive axial preload along the spinal curvature produces more comparable results to in-vivo studies, providing an important guideline for experiments investigating range of motion and spinal stability.;The purpose of the second aim was to determine the motion response of the spinal joint to pure bending in any plane around its circumference. Towards that goal, the three-dimensional motion envelope of two-level spinal segments was analyzed. Since the posterior elements were intact, restriction in motion caused by zygapophyseal joints resulted a smaller displacement for extension than in flexion. Characterization of the motion envelope can provide a better understanding of the complex joint kinematics and assist in the design of new implants with the goal of restoring joint function.;The purpose of the third aim was to investigate the strength of a single vertebral body during compression fracture by following the path of least resistance. In vivo, the spinal column continuously maintains equilibrium and minimizes stress via a complex system of muscles, tendons and ligaments such that each vertebra experiences a predominantly axial load. In a typical experiment, compressive loads are also applied axially but unwanted shear forces and moments are generated as well. Using a novel testing approach, identification of the weakest region of a vertral body, and following this path of least resistance, a true measure of vertebral strength, we were able to demonstrate the effect of current experimental limitations in overpredicting bone strength. |
