Cranial Nerves: Overview and Anatomy

The cranial nerves are 12 pairs of nerves originating directly from the brain and brainstem.

These nerves are a part of the peripheral nervous system transmitting sensory and motor information between the CNS and the rest of the PNS.

Cranial nerves have names based on their function or the structure they innervate. They are also numbered using Roman numerals from I to XII, starting from the anterior to the posterior of the brain.

These nerves are categorized as special sensory, motor, or mixed nerves.

Nerves I, II, and VIII are the special sensory nerves associated with olfaction, vision, hearing, and equilibrium.

Nerves III, IV, VI, XI, and XII are classified as motor nerves. They innervate the eye, neck, and tongue muscles.

Nerves V, VII, IX, and X are mixed nerves innervating the head, oral cavity, and visceral organs. 

Four cranial nerves, III, VII, IX, and X, are also the components of the parasympathetic division of the ANS and innervate cardiac muscles, smooth muscles, and glands.