Fig. 42-19. Superior aspect of the right temporal bone. (Ct. fig. 42-17.) The asterisk marks the portion of the petrous part (tegmen tympani) that turns downward into the squamotympanic fissure. The trigeminal impression, which lodges the trigeminal ganglion, is immediately behind the apex of the bone and the termination of the carotid canal. Click for high resolution image.