Traumatic avulsion fracture of the occipital condyles and clivus: a case report.

A 25-year-old male was found dead on a river bank. Wounds and injuries were found on the corpse, and a bloodstain was found on the face from blood discharged from the oral and nasal cavities. Since the man was considered the victim of a traffic accident, a forensic autopsy was carried out. At the time of autopsy, severe bruises and wounds were found on the occiput, the nape and the dorsal side of the lower extremities. There was a fracture line in the bilateral occipital condyles through the lower part of the clivus and the head was unstable in relation to the neck. The medulla oblongata was severed near the fracture site and the basilar artery was also torn at the branching end of the posterior cerebral arteries. The fracture of the occipital condyles and clivus was considered to be avulsed due to hyperflexion of the neck joint by a blunt impact onto the occiput. Anterior traction of the skull following the fracture was supposed to have accompanied the injuries of the medulla oblongata and the basilar artery. In this autopsy case, the authors observed an unusual type of fracture in the posterior cranial fossa.