The concern of this paper is the study of mechanical tolerance limits of intracranial injuries, such as epidural, subdural, subarachnoidal, coup and contracoup contusions and brain lacerations, by the investigation of real world accidents. Twenty-five fatal pedestrian accidents are analysed with respect to pedestrian kinematics, head impact velocity, contact areas, and mechanical loading as related to sustained head injuries. From the analysis, upper and lower tolerance limits are defined. Above a mean acceleration of 250 g subarachnoidal hematoma, above 300 g subdural hematoma, brain, lacerations, and contre-coup contusions are regularly observed. Due to the uncertainties in reconstruction and reconstruction and analysis, values marking the amount of loading below which these injuries are never observed are rather low and range between 20 and 80 g for long pulse durations. (A)
Abstract