Cranial foramina

The cranial foramina allow passage of cranial nerves, arteries and veins. Numerous foramina of the skull are described, and vary in size and number, with age. Here a short list of the main cranial foramina with their contents :

• Cribriform (olfactory) foramina: olfactory nerve (I)

• Optic canal: optic nerve (II), ophthalmic artery and dural sheath of optic nerve

• Superior orbital fissure: oculomotor nerve (III), trochlear nerve (IV), ophthalmic division of the trigeminal nerve (V1), abducent nerve (VI) and ophthalmic veins

• Foramen ovale: mandibular division of the trigeminal nerve (CN V3), accessory meningeal branch of maxillary artery, emissary vein and lesser petrosal nerve

• Foramen rotundum: maxillary division of the trigeminal nerve (V2)

• Foramen spinosum: middle meningeal artery

• Foramen lacerum: greater petrosal nerve

• Carotid canal: internal carotid artery

• Internal acoustic foramen: facial nerve (VII) and vestibulocochlear nerve (VIII)

• Jugular foramen: glossopharyngeal nerve (IX), vagus nerve (X), descending portion of the spinal accessory nerve (XI) and internal jugular vein

• Hypoglossal canal: hypoglossal nerve (CNXII)

• Foramen magnum: brainstem/spinal cord, vertebral arteries, ascending portion of the spinal accessory nerve (XI)