Pathology of experimental traumatic craniocerebral missile injury

The neuropathological alterations in sheep associated with head wounds inflicted by a .22 calibre rifle are reported. Brain damage was manifest as a permanent haemorrhagic wound cavity produced by crushing and laceration of tissue during missile penetration, secondary tracks due to bone and bullet fragments, widely distributed stretch injuries to blood vessels, nerve fibres and neurons as a consequence of the radial forces of the temporary cavity which develops as a bullet penetrates tissue, marked subarachnoid and intraventricular haemorrhage, and distortion and displacement of the brain.