Internal surface of cranial base

The floor of the cerebral cavity is made of the middle and rostral cranial fossae and forms the internal surface of the cranial base (BAsis crani interna).

It is formed by the basilar part of the occipital bone and by the sphenoid and ethmoid bones, as well as by a small surface of the auricular part of the temporal bone.

Two transversal reliefs that run on each side of the lateral wall subdivide it in three regions:

-the caudal relief is formed by the ventral end of the spheno-occipital crests already described that are extended, from one foramen lacerum to the other, by a soft transversal ridge; it separates the caudal cranial fossa from the middle cranial fossa.

-the rostral relief, less prominent, is formed by the wing of the presphenoid bone and is continued until the endocranial surface of the frontal bone; it separates the middle cranial fossa from the rostral cranial fossa.