In order to illustrate orthotic and surgical scoliosis correction mechanisms, an interpolation method has been developed using a spherical joint to represent the vertebral articulation. The interpolation, computed from two 3D reconstructions of the scoliotic spine (before and after correction) obtained from a stereoradiographic technique, is based on the hypothesis that there are no intervertebral translations. A model of the spine is constructed based on a series of spherical joints with rigid interconnections and L5 anchored at the reference base. Intermediate geometries are then generated by interpolating the orientation in a quaternion space in which the vertebrae are placed in the global 3D space using their relative positions. Visualization is done via a computer graphic software providing an animation of the correction process.