Derivation of stiffness matrices for modeling a human cervical spine

Based on the published experimental data under static loading condition, stiffness matrices of the cervical spine were developed. These matrices simulate well the static response of the cervical spine as shown by the authors in an earlier work, while for a dynamic simulation these matrices need some modifications in order to achieve more accurate results. We present a method, in the form of a constrained optimization problem, that facilitates the evaluation of the stiffness matrices to be used in a dynamic simulation. The intervertebral disk and the ligaments are represented by an equivalent stiffness matrix whose elements are assumed to be constant over the entire range of mobility. With a set of new stiffness matrices derived by the proposed method, the dynamic simulation showed a good agreement with the observed motion data.