Position paper on fatal abusive head injuries in infants and young children

This article represents the work of the National Association of Medical Exa miners Ad Hoc Committee on shaken baby syndrome. Abusive head injuries incl ude injuries caused by shaking as well as impact to the head, either by dir ectly striking the head or by causing the head to strike another object or surface. Because of anatomic and developmental differences in the brain and skull of the young child, the mechanisms and types of injuries that affect the head differ from those that affect the older child or adult. The mecha nism of injury produced by inflicted head injuries in these children is mos t often rotational movement of the brain within the cranial cavity. Rotatio nal movement of the brain damages the nervous system by creating shearing f orces, which cause diffuse axonal injury with disruption of axons and teari ng of bridging veins, which causes subdural and subarachnoid hemorrhages, a nd is very commonly associated with retinal schisis and hemorrhages. Recogn ition of this mechanism of injury may be helpful in severe acute rotational brain injuries because it facilitates understanding of such clinical featu res as the decrease in the level of consciousness and respiratory distress seen in these injured children. The pathologic findings of subdural hemorrh age, subarachnoid hemorrhage, and retinal hemorrhages are offered as "marke rs" to assist in the recognition of the presence of shearing brain injury i n young children.