Modeling of jaw-head-neck dynamics during whiplash.

Clinicians report signs and symptoms of temporomandibular joint (TMJ) disorders in many patients who have experienced automobile rear-end collisions involving neck hyperextension (whiplash). In order for relationships between TMJ disorders and rear-end collisions to be explored, the dynamic response of the jaw to hyperextension of the neck associated with automobile rear-end collisions needs to be quantified. To achieve this goal, we extended an existing head-neck model by adding a movable jaw, and performed preliminary computer simulations of the jaw movements during rear-end collisions at 6.71 ms-1 (15 mph) and 13.41 ms-1 (30 mph). The initial computer simulations produced promising kinematic and dynamic results, such as: relative angle between the head and jaw (jaw-opening angle), predicted TMJ torques, and displacement and linear acceleration of the jaw's center of mass. However, the absolute values and time course of our results must be viewed with caution, since the jaw model has not yet been validated with experimental data. Nevertheless, the modeling approach, detailed in this study, shows good promise for eventually providing quantitative dynamic information about the jaw-head-neck system during impulsive loading.