Biomedical subjects
J M Stenger
Publications and source records attributed to J M Stenger.
Mouthguards: protection against shock to head, neck and teeth.
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Physiologic dentistry with Notre Dame athletes.
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Equilibrium and non-equilibrium dynamics of the cranio-mandibular complex and cervical spine.
A dynamic model of the inverted pendulum characteristics of the head and cervical spine is presented. Using simple approximations and a single rotational-degree-of-freedom approach, the model is shown to conform to the classical mathematical description of an inverted pendulum motion. It also exhibits the well-known point of unstable equilibrium which is a standard property of such systems. Specific predictions of this theoretical description are compared against other values for the tilt, angular velocity and acceleration of the head during acceleration-sled testing, and with the Kapitza relation for mechanical-dither stabilization of an inverted pendulum. Numerical evaluations of the dynamic variables, resonant frequencies and time constants important to the problem are provided, and suggestions are made about how further results might be derived from extended versions of the model. This approach can now be refined to serve as a testing ground for analysing the biomechanics of traumatic neck injuries and for interpreting the possible roles that mandibular dysfunctions and dental malocclusion may play in disorders of the cervical spine. (Some background needed for exploring the latter possibility is presented.)
A biomechanical model of the craniomandibular complex and cervical spine based on the inverted pendulum.
The head and neck constitute an inverted pendulum that is stabilized during consciousness by neuromuscular restoring forces. An analysis of the dynamics of this inverted pendulum suggests that the mechanics of the mandible and temporomandibular joint might couple into those of the pendulum's stabilization process. In this article, physical principles of the inverted pendulum model as these apply to the head and neck are explored, and the authors describe implications of mandibular mechanics for the forces acting on the head and neck at equilibrium. This novel application of the inverted pendulum model predicts that alteration or pathology of temporomandibular mechanics would lead to perturbations of the normal forces acting in the head and neck. Under certain circumstances, these perturbations could be expected to contribute to symptoms and result in additional or accelerated degenerative effects.