[Traumatic basal subarachnoid hemorrhage]

Massive subarachnoid hemorrhage may occur on a traumatic basis. The injury is most often sustained by a blow with a clenched fist against the posterolateral part of the cranial basis, but the injury may also occur in relation to an accident. The condition is rare, most often occurring in alcohol intoxicated men. The victim typically collapses immediately and usually dies within a few minutes. The origin of the bleeding may be the vertebral artery on the neck or the intercranial basal brain arteries. In some cases the origin of the bleeding cannot be located. The pathogenetic mechanisms have been a subject of discussion. The damage to the artery may occur in relation to a fracture of the transverse process of the atlas or in relation to subluxations in the cervical vertebral column. The arterial rupture may occur in both normal and abnormal arteries. In many of the cases the trauma may be very slight. This has, of course, important legal implications.