Putting the head on the neck: A realistic biomechanic model of human head-neck mechanics

A realistic model of the human head-neck mechanics has to include not only parameters like size, elasticity and density of anatomical head and neck parts, but also a model of the postural reflexes. To this end, we have combined a realistic model of the human balance system with a multi-body simulation of the human neck. This provided us with a closed-loop model: linear and rotational movements of the head stimulate the balance system; this activates the vestibulo-collic reflex, which modifies the activation of the neck muscles; the change in the neck mechanics in turn affects the head movement. We give a short presentation of the model of the balance system, especially the finite-element model of the otoliths that measure linear accelerations, and present our multibody- dynamics model of the human neck.