Floor and Contents of the Middle Cranial Fossa

Abstract

The bony floor of the middle cranial fossa is bounded rostrally by the posterior border of the lesser wing of the sphenoid and its lateral extension, which we term the crista alaris (Sylvii). Below this bony ridge the greater wing of the sphenoid forms a hollow for the pole of the temporal lobe. This hollow extends forwards for a variable distance. Further posteriorly, the basal gyri of the temporal lobe lie against the floor of the temporal fossa. In its medial part the greater wing extends further dorsally than in its lateral part, and the squamous temporal bone makes up much of the floor and lateral wall of the middle fossa. The dorsal boundary of the bony floor of the middle cranial fossa is formed by the anterior surface of the petrous part of the temporal bone. The floor of the middle fossa carries a number of portals for the passage of cranial nerves and vessels.