In an ongoing effort to develop an accurate model of human head impact relationships, two series of impacts were performed on the side of a human cadaver head at the junction of the temporal and parietal bones. When four sequential impacts were performed on a single embalmed specimen, a good correspondence was found between peak head acceleration and Head Injury Criterion, and the adequacy of instrument placement and data analysis was confirmed. Five impacts on individual unembalmed cadavers indicated that side impacts produced pressure gradients in the brain. These superimposed gradients were proportional to the magnitudes of the head acceleration components, the largest of which was in the direction of impact and produced positive pressures near the impact and negative ones opposite the impact. A pressure-limiting mechanism acted on the side of the brain opposite the impact. Subarachnoid hemorrhages occurred on the high stress and strain brain surfaces. Approximate values for the pressures were determined in computer simulations. Changes in the model and instrumentation are needed to improve the accuracy of the computed pressures. The acceleration traces contained vibration or noise which made calculation of rotation acceleration and velocity impossible. A better representation of the midsaggital sinus is needed.
Abstract