Fig. 2

Right and left axial petrous temporal bone CT. Right axial CT shows a medial subtype of horizontal temporal bone fracture. There is a fracture of the posterior petrous surface (white arrow) extending anteriorly through the fundus of the internal auditory canal to the geniculate fossa of the facial nerve (black arrow). Separate fracture through the petrous apex indicated by arrowhead. Left axial CT shows a lateral subtype of horizontal temporal bone fracture. There is a fracture of the posterior petrous surface (white arrow) lateral to the internal auditory canal. It involves the vestibule and extends through the tympanic segment of the facial nerve canal (black arrow). The fracture exits through the anterior wall of the middle ear cavity into the squamous temporal bone