A mathematical model is developed for a three-dimensional force analysis of the human vertebral column. The vertebrae are idealized as rigid bodies, while the discs, ligaments, and connective tissues are represented by deformable elements. An incremental stiffness method which accounts for nonlinearities due to large displacements is used. Preliminary results are presented for the behavior of an isolated, ligamentous column under traction, lateral loads, and compressive loads which result in buckling.