How many pairs of cranial nerves emerge from the human brain?

The human brain gives rise to 12 pairs of cranial nerves.

These nerves are numbered with Roman numerals I through XII and connect the brain or brainstem with structures in the head, neck, and, in the case of the vagus nerve, much of the trunk. Their functions include smell, vision, eye movement, facial sensation, hearing, swallowing, and control of several internal organs.

The phrase “12 pairs” means 12 nerves on the left and 12 corresponding nerves on the right, for 24 individual cranial nerves. The first two pairs, the olfactory and optic nerves, are closely associated with the forebrain, while most of the remaining cranial nerves emerge from the brainstem.

A common mix-up is confusing cranial nerves with spinal nerves. Humans have 31 pairs of spinal nerves, which leave the spinal cord rather than the brain. Some researchers also discuss a tiny terminal nerve, but standard anatomy still teaches 12 cranial-nerve pairs.