A geometric model for cylinder-cylinder impact with application to vertebrae motion simulation

The reconstruction of inter-vertebral motion of the human cervical spine, although basically understood, still poses many open problems. This is so because pairs of vertebrae undergo in general six-dimensional motion relative to one another, but display a high degree of coupling between gross translational and rotational degrees-of-freedom due to restraints imposed by ligaments and muscles and the compliant nature of the intervertebral discs (White and Panjabi, 1990). Described in this paper is the mathematical modeling of a vertebrae pair using multibody methods and impact; analysis techniques with elementary contact geometry for the facet joints. Tilt? results are compared with existing approaches and with experimental data, showing a good agreement with the latter and an efficiency boost compared to existing approaches by a factor of 350. The investigations are focused on the vertebrae pair C5-C6 but can be easily extended to other vertebrae.