The cranial nerves are the 12 paired sets of nerves that arise from the cerebrum or brainstem and leave the central nervous system through cranial foramina rather than through the spine. The cranial nerves are numbered one to twelve, always using the Roman numerals, I to XII. Most have cranial nerve nuclei located in the brainstem.
The third and fourth cranial nerves originate from the midbrain:
The middle four cranial nerves originate from the pons:
- trigeminal nerve (CN V)
- abducens nerve (CN VI)
- facial nerve (CN VII)
- vestibulocochlear nerve (CN VIII)
The final four cranial nerves originate from the medulla oblongata:
- glossopharyngeal nerve (CN IX)
- vagus nerve (CN X)
- accessory nerve (CN XI)
- hypoglossal nerve (CN XII)
See mnemonic for cranial nerves.
History and etymology
Thomas Willis (1621–1675) was responsible for the original numbering of the cranial nerves, as well as his famous anatomical circle in the brain.