Internal forces in the spine modelled as an arch

The work reported here presents a parametric solid model of the spine, loading systems of the spine and a extracted arch spine model in which the body weight and external loads are treated as forces applied at appropriate points on the spine and muscle and ligament forces are treated as reaction forces applied to both ends of the spine. The model extends the arch spine approach by using optimisation techniques to find a better fitting thrust line compared with the previous arch model in the literature, and calculates the internal forces between the vertebrae in the spine. Case studies show the reasonable values of the internal forces (1.1-1.5 kN) in the arch spine. The values are much less than that of lever models (up to 6.6 kN).