Which of the following cavities are separated from the middle cranial fossa by a thin layer of bone?
The middle ear cavity is separated from the middle cranial fossa by the tegmen tympani, a thin plate of the petrous pa of the temporal bone. A pa of the roof of the sphenoid bone forms the floor of the hypophyseal fossa. The other pairs of sinuses or bony cavities are not separated from the middle cranial cavity.