This document lists the foramina and apertures found in the three cranial fossae and describes their contents. The anterior cranial fossa contains foramina for the nasal emissary vein, olfactory nerves, and vessels/nerves associated with the ethmoid bone. The middle cranial fossa contains optic canals, fissures, and foramina transmitting cranial nerves and vessels. The posterior cranial fossa transmits the medulla, vertebral arteries, cranial nerves, veins and arteries through openings like the foramen magnum and jugular foramen.

1. Foramina and other apertures of cranial fossae and contents
Foramina/Apertures Contents
Anterior cranial fossa
Foramen cecum Nasal emissary vein (1% of population)
Cribriform foramina in cribriform plate Axons of olfactory cells in olfactory epithelium
that form olfactory nerves
Anterior and posterior ethmoidal foramina Vessels and nerves with same names
Middle cranial fossa
Optic canals Optic nerves (CN II)
Ophthalmic arteries
Superior orbital fissure Ophthalmic veins
Ophthalmic nerve (CN V1)
CN III
CN IV
CN VI
Sympathetic fibers
Foramen rotundum Maxillary nerve (CN V2)
Foramen ovale Mandibular nerve (CN V3)
Accessory meningeal artery
Foramen spinosum Middle meningeal artery & vein
Meningeal branch of CN V3
Foramen laceruma Deep petrosal nerve
Some meningeal arterial branches
Small veins
Groove or hiatus of greater petrosal nerve Greater petrosal nerve
Petrosal branch of middle meningeal artery
Posterior cranial fossa
Foramen magnum Medulla & meninges,
Vertebral arteries,
CN XI,
Dural veins,
Anterior & posterior spinal arteries
Jugular foramen CN IX,
CN X,
CN XI;
Superior bulb of internal jugular vein;
Inferior petrosal sinus
Sigmoid sinus;
Meningeal branches of ascending pharyngeal and
occipital arteries
Hypoglossal canal Hypoglossal nerve (CN XII)
Condylar canal Emissary vein that passes from sigmoid sinus to
vertebral veins in neck
Mastoid foramen Mastoid emissary vein from sigmoid sinus
Meningeal branch of occipital artery
a The internal carotid artery and its accompanying sympathetic and venous plexuses actually pass horizontally across (rather than vertically through) the area of the foramen lacerum, an
artifact of dry crania, which is closed by cartilage in life.