The arcuate eminence is not a protrusion of the superior semi-circular canal but a trace of sulcus on the temporal lobe.

Thirteen cadavers (26 temporal bones) were examined to show the arcuate eminence, especially its correspondence to the superior semicircular canal and inferior surface of the temporal lobe. Arc-like eminences on the petrous bone were observed in 92 per cent of specimens, however, they did not exactly correspond to the superior semi-circular canal. Some eminences corresponded to sulci of the temporal lobe of which most were traces of the occipitotemporal sulcus. On the other hand, a dull, smooth and even domed eminence existed in nine temporal bones independently of the arc-like eminence. Those eminences corresponded to each superior semi-circular canal in only three out of nine specimens. The arcuate eminence was listed as an important landmark in the middle cranial fossa approach. However, in order to drill out the internal auditory canal safety, surgeons should rely on other landmarks or apply other methods from our data.