BRAIN INJURY PATTERNS IN FATALLY INJURED PEDESTRIANS

To study the relationship between the severity of impact to the head a nd the severity and distribution of injury to the brain in fatally inj ured pedestrians, events in vehicle-pedestrian collisions were reconst ructed to determine the peak linear and angular acceleration sustained by the pedestrians' heads. The nature and distribution of injuries to the brain were determined by neuropathologic examination of coronal s ections of the brain. Study of 13 cases with occipital impacts and 18 with lateral impacts showed that the brain appeared to be more suscept ible to injury from lateral impacts. The frontal and temporal regions appeared to be more susceptible to injury at low accelerations in occi pital impacts, providing an explanation for ''coup'' and ''contrecoup' ' injuries. For occipital impacts, a positive relationship was found b etween linear acceleration and the extent of injury to the brain, sugg esting that there was a threshold for observable and concussive brain injury at about 1500 m/s(2) peak linear acceleration. These findings a re important for the development of measures for preventing brain inju ries.