In this study, radio opaque markers were placed in the skull and neutral density markers were placed in the brain in two vertical columns in the occipitoparietal and temporoparietal regions. A bi-planar high-speed x-ray system was used to track the motion of these markers. Due to limitations in current technology to record the x-ray image on high-speed video cameras, only low speed impact data were available. A previously developed finite element model (FEM) of the brain (See C 5834 (IRRD 882991) simulating blunt head impact was used to study the feasibility of using this model to obtain relative displacement of the same magnitude as that obtained experimentally. The model was modified here. Although the cerebral spinal fluid (CSF) remained as a layer of material with a low shear modulus, a sliding interface was introduced to simulate the interaction between the CSF and pia matter. The model predictions corresponded with brain displacement data obtained from cadaveric experiments. The relative skull/brain displacement-time histories predicted by the new model agreed well with those obtained experimentally. The model was also run at higher impact speeds to obtain intracranial pressure and displacement histories. The computed coup/contrecoup pressures and contact forces predicted by the model compared favourably with the experimental data published by A. Nahum et al. (See B 17925) IRRD 247788).
Abstract