The geometry of brain contusion: relationship between site of contusion and direction of injury.

Up to a fifth of Accident and Emergency admissions are head-injury related. Alcohol is involved in a large proportion of adult head injuries and although the incidence of death due to head injury (HI) is relatively low, long-term sequelae including cognitive disturbance are frequent. Contrecoup contusions (CCs) have been observed commonly in closed head injuries and may be an independent factor in long-term neuro-disability. The mechanisms of their formation are still under debate. The aim of this study was to define the relationship between the direction of the blow to the head and the location of brain contusion after HI. The location of scalp injuries was used as a surrogate for the direction of the blow to the head. Between January 2007 and March 2009, 358 cases of HI were treated at the Newcastle Neurosurgery Unit. Of these, 129 had contusions. Of these, 100 scans were available. The site of scalp injury could be identified in 98 cases and these were used for the study. Sixty-six percent of scalp injuries were to the back of the head. Most contusions (77%) were contracoup affecting the frontal and temporal lobes. Sixty percent of the injuries were inflicted by a fall from a standing position striking the back of the head on a paved surface, most commonly in the context of assaults or fighting.