This
projection is of the base of the skull. The sphenoid air sinus is well shown.
The numerous exit foramina from the skull are easily identified. Look for
enlargement of the foramen spinosum which can occur in vascular vault
meningiomas with a large external carotid arterial supply. Check the petrous
apex and the region of the jugular foramen. Check the middle ear and its
ossicles. Identify the three bony lines which overlap anteriorly: the greater
wing of the sphenoid, the posterior wall of the orbit and the posterior wall of
the maxillary antrum.
