Cranial nerves: Nerves that emerge from or enter the skull (the cranium), as opposed to the spinal nerves which emerge from the vertebral column. Cranial nerves come directly from the brain through the skull.

There are 12 cranial nerves each of which is accorded a Roman numeral and a name:

• Cranial nerve I: The olfactory nerve,
• Cranial nerve II: the optic nerve,
• Cranial nerve III: the oculomotor nerve,
• Cranial nerve IV: the trochlear nerve,
• Cranial nerve V: the trigeminal nerve,
• Cranial nerve VI: the abducent nerve,
• Cranial nerve VII: the facial nerve,
• Cranial nerve VIII: the vestibulocochlear nerve,
• Cranial nerve IX: the glossopharyngeal nerve,
• Cranial nerve X:the vagus nerve,
• Cranial nerve XI: the accessory nerve, and
• Cranial nerve XII: the hypoglossal nerve.

The cranial nerves are nerves of the brain.