In an earlier series of papers, we reported on the results of a study of frontal impacts to cadaver heads which were protected and unprotected. New data is presented to quantify head response to laterally directed impacts. The temporo-parietal area of the head in stationary unembalmed cadaver subjects was struck by a rigid impactor mass. Both helmeted and unhelmeted exposures were compared. Data collected included impactor energy, intracranial pressures at selected locations, and composite analyses from a nine accelerometer array system. In addition the data was entered into a finite element head model. Stresses and strains were predicted for various intracranial locations. The applicability of head injury indices in understanding lateral head impact are commented on.