Impact-induced intracranial pressure caused by an accelerated motion of the head or by skull deformation; an experimental study using physical models of the head and neck, and ones of the skull.

An impact incurred by the movable head may bring about a change in intracranial pressure and this change may play an important part in the occurrence of the cerebral contusion. We have carried out the following experiments to determine whether the intracranial pressure change was attributed to an accelerated motion of the head or to a skull deformation. In the blow experiment in which the head was accelerated, a positive peak in the intracranial pressure was recorded immediately after impact at the impact site and a negative one at a site opposite the impact. In the one in which the skull could be deformed, the intracranial pressure curves at both sites contained harmonics. The modal analysis revealed an inbending in the frontal and occipital regions of the skull and an outbending in the parietal and temporal regions immediately after impact, followed by a reverse deformation. Regarding the intracranial pressure change, positive pressures were recorded in the frontal and occipital regions immediately after impact, followed by a negative one. This study demonstrated that the positive and negative peaks were caused by the accelerated motion of the head, and that the curve of the intracranial pressure changes contained harmonics which were caused by the deformation of the skull.