Twelve pairs of cranial nerves emerge from the base of the brain. The first two 'nerves' are actually part of the central nervous system (CNS), serving olfaction and vision. The rest are like the spinal nerves, in that they contain axons of the peripheral nervous system (PNS). As the illustration shows, however, a single nerve often has fibres performing many functions. Knowledge of the nerves and their functions is valuable in the diagnosis of neurological disorders. It is important to recognize that the cranial nerves have associated cranial nerve nuclei in the midbrain, pons, and medulla. Examples are the cochlear and vestibular nuclei, which receive information from cranial nerve VIII.
| Nerve Number and Name | Type of Axons | Important Functions | |
| 1. | I. Olfactory |
Special sensory |
Sensation of smell |
| 2. | II. Optic |
Special sensory |
Sensation of vision |
| 3. | III. Occulomotor |
Somatic motor Visceral motor |
Movements of the eye and eyelid Parasympathetic control of pupil size |
| 4. | IV. Trochlear |
Somatic motor |
Movements of the eye |
| 5. | V. Trigeminal |
Somatic sensory Somatic motor |
Sensation of touch to the face Movement of muscles for chewing |
| 6. | VI. Abducens |
Somatic motor |
Movements of the eye |
| 7. | VII. Facial |
Somatic sensory Special sensory |
Movement of muscles for facial expression Sense of taste in front 2/3s of tongue |
| 8. | VIII. Auditory-vestibular |
Special sensory |
Sensation of hearing and balance |
| 9. | IX. Glossopharyngeal |
Somatic motor Visceral motor Special sensory Visceral sensory |
Movement of muscles in the throat Parasympathetic control of salivary glands Sense of taste in rear 1/3 of tongue Detection of blood pressure in aorta |
| 10. | X. Vagus |
Visceral motor Visceral sensory Somatic motor |
Parasympathetic control of heart and lungs Sensation of pain associated with viscera Movement of muscles in throat |
| 11. | XI. Spinal accessory |
Somatic motor |
Movement of muscles in throat and neck |
| 12. | XII. Hypoglossal |
Somatic motor |
Movement of tongue |
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