Foramina in the Base of the Skull
1. Petrotympanic fissure
■ Chorda tympani and often anterior tympanic artery.
2. Stylomastoid foramen
■ Facial nerve.
3. Incisive canal
■ Nasopalatine nerve and terminal part of the sphenopalatine or greater palatine vessels.
4. Greater palatine foramen
■ Greater palatine nerve and vessels.
5. Lesser palatine foramen
■ Lesser palatine nerve and vessels.
6. Palatine canal
■ Descending palatine vessels and the greater and lesser palatine nerves.
7. Pterygoid canal
■ Runs from the anterior wall of the foramen lacerum to the pterygopalatine fossa and transmits the nerve of the pterygoid canal (vidian nerve).
8. Sphenopalatine foramen
■ Sphenopalatine vessels and nasopalatine nerve.
A. Anterior Cranial Fossa
1. Cribriform plate
■ Olfactory nerves.
2. Foramen cecum
■ Occasional small emissary vein from nasal mucosa to superior sagittal sinus.
3. Anterior and posterior ethmoidal foramina
■ Anterior and posterior ethmoidal nerves, arteries, and veins.
B. Middle Cranial Fossa
1. Optic canal
■ Optic nerve, ophthalmic artery, and central artery and vein of the retina.
2. Superior orbital fissure
■ Oculomotor, trochlear, and abducens nerves; ophthalmic division of trigeminal nerve; and ophthalmic veins.
3. Foramen rotundum
■ Maxillary division of trigeminal nerve.
4. Foramen ovale
■ Mandibular division of trigeminal nerve, accessory meningeal artery, and occasionally lesser petrosal nerve.
5. Foramen spinosum
■ Middle meningeal artery.
6. Foramen lacerum
■ Nothing passes through this foramen, but the upper part is traversed by the internal carotid artery and greater and deep petrosal nerves en route to the pterygoid canal.
C. Posterior Cranial Fossa
1. Internal auditory meatus
■ Facial and vestibulocochlear nerves and labyrinthine artery.
2. Jugular foramen
■ Glossopharyngeal, vagus, and spinal accessory nerves and beginning of internal jugular vein.
3. Hypoglossal canal
■ Hypoglossal nerve and meningeal artery.
4. Foramen magnum
■ Spinal cord, spinal accessory nerve, vertebral arteries, venous plexus of vertebral canal, and anterior and posterior spinal arteries.
5. Condyloid foramen
■ Condyloid emissary vein.
6. Mastoid foramen
■ Branch of occipital artery to dura mater and mastoid emissary vein.
7. Carotid canal
■ Internal carotid artery and sympathetic nerves (carotid plexus)
8. Hiatus of facial canal
■ Greater petrosal nerve.
D. Foramina in the Front of the Skull
1. Zygomaticofacial foramen
■ Zygomaticofacial nerve.
2. Supraorbital notch or foramen
■ Supraorbital nerve and vessels.
3. Infraorbital foramen
■ Infraorbital nerve and vessels.
4. Mental foramen
■ Mental nerve and vessels.
