If we took a horizontal section of the cranium, in particular the inferior part and looked at it from above, we would see the internal surface of the cranial base (basis cranii interna).

The internal surface of the cranial base consists of three so-called cranial fossae:

• Anterior cranial fossa (fossa cranii anterior), which is limited from behind by the lesser wings and the tuberculum sellae of the sphenoid bone

  

• Middle cranial fossa (fossa cranii media)

  

• Posterior cranial fossa (fossa cranii posterior), which is bordered from behind by the superior border of the petrous part of the temporal bone and the dorsum sellae.

On the internal surface of the cranial base, we can see numerous foramina and fissures, through which vessels and nerves pass. Let us examine them in more detail.

Title	Contents
Anterior cranial fossa
Cribriform foramina (foramina cribrosa)	Anterior ethmoidal artery, ethmoidal veins, olfactory nerve

Foramen caecum (foramen caecum)

None

Middle cranial fossa
Optic canal (canalis opticus)	Optic nerve

Superior orbital fissure (fissura orbitalis superior)

Anterior meningeal branch of the anterior ethmoidal artery, superior ophthalmic vein, oculomotor nerve, trochlear nerve, abducent nerve, ophthalmic nerve

Internal opening of carotid canal (canalis caroticus)

Internal carotid artery, internal carotid venous plexus, internal carotid sympathetic plexus

Foramen rotundum (foramen rotundum)

Maxillary nerve

Foramen ovale (foramen ovale)

Meningeal branch of the middle meningeal artery, emissary vein, mandibular nerve

Foramen spinosum (foramen spinosum)

Middle meningeal artery and veins, meningeal branch of the mandibular nerve

Hiatus for greater petrosal nerve (hiatus canalis nervi petrosi majoris)

Greater petrosal nerve, petrosal branch of the middle meningeal artery, auditory vein

Hiatus for lesser petrosal nerve (hiatus canalis nervi petrosi minoris)

Lesser petrosal nerve, superior tympanic artery

Foramen lacerum (foramen lacerum)

Internal carotid artery, artery of pterygoid canal, emissary veins, nerve of pterygoid canal

Posterior cranial fossa
Internal acoustic meatus (meatus acusticus internus)	Labyrinthine artery and veins, facial nerve, Vestibulocochlear nerve

Mastoid foramen (foramen mastoideum)

Meningeal branch of the occipital artery, mastoid emissary vein

Jugular foramen (foramen jugulare)

Internal jugular vein, posterior meningeal artery, glossopharyngeal nerve, vagus nerve, accessory nerve, meningeal branch of vagus nerve

Foramen magnum (foramen magnum)

Vertebral arteries, anterior and posterior spinal arteries, basilar venous plexus, myelencephalon

Condylar canal (canalis condylaris)

Condylar emissary vein

Hypoglossal canal (canalis nervi hypoglossi)

Hypoglossal nerve

Opening of cochlear canaliculus (canaliculus cochleae)

Ductus perilymphaticus, vein of cochlear canal

Opening of vestibular aqueduct (aqueductus vestibuli)

Endolymphatic duct

Dictionary

Cranial fossae

internal surface of cranial base

basis cranii interna

anterior cranial fossa

fossa cranii anterior

middle cranial fossa

fossa cranii media

posterior cranial fossa

fossa cranii posterior

cribriform foramina

foramina cribrosa

foramen caecum

foramen caecum

optic canal

canalis opticus

superior orbital fissure

fissura orbitalis superior

carotid canal

canalis caroticus

foramen rotundum

foramen rotundum

foramen ovale

foramen ovale

foramen spinosum

foramen spinosum

hiatus for greater petrosal nerve

hiatus canalis nervi petrosi majoris

hiatus for lesser petrosal nerve

hiatus canalis nervi petrosi minoris

foramen lacerum

foramen lacerum

internal acoustic meatus

meatus acusticus internus

mastoid foramen

foramen mastoideum

jugular foramen

foramen jugulare

foramen magnum

foramen magnum

condylar canal

canalis condylaris

hypoglossal canal

canalis nervi hypoglossi

cochlear canaliculus

canaliculus cochleae

vestibular aqueduct

aqueductus vestibuli