The Cranial Nerves

Cranial Nerves Cranial nerves are spinal nerves that come out of the brain instead of the spinal cord.

Cranial Nerves Cranial nerves are spinal nerves that come out of the brain instead of the spinal cord. They can serve either a sensory, motor or mixed (both) functions.

Filaments of olfactory nerve (I) Frontal lobe Olfactory bulb Olfactory tract Optic nerve (II) Temporal lobe Optic chiasma Infundibulum Optic tract Facial nerve (VII) Oculomotor nerve (III) Vestibulo- cochlear nerve (VIII) Trochlear nerve (IV) Trigeminal nerve (V) Glossopharyngeal nerve (IX) Abducens nerve (VI) Vagus nerve (X) Cerebellum Accessory nerve (XI) Medulla oblongata Hypoglossal nerve (XII) (a)

Cranial nerves I – VI Sensory function Motor function PS* fibers I Olfactory Yes (smell) No No II Optic Yes (vision) No No III Oculomotor No Yes Yes IV Trochlear No Yes No V Trigeminal Yes (general sensation) Yes No VI Abducens No Yes No Cranial nerves VII – XII Sensory function Motor function PS* fibers VII Facial Yes (taste) Yes Yes VIII Vestibulocochlear Yes (hearing and balance) Some No IX Glossopharyngeal Yes (taste) Yes Yes X Vagus Yes (taste) Yes Yes XI Accessory No Yes No XII Hypoglossal No Yes No *PS = parasympathetic (b)

Function

Mnemonic There are a variety of mnemonics that help you remember the cranial nerves. “On occasion, our trusty truck acts funny, very good vehicle anyhow”

Mnemonics There are a variety of mnemonics that help you remember the cranial nerves. “On occasion, our trusty truck acts funny, very good vehicle anyhow” For Function “Some say marry money but my mother say bad business marry money”

Examination of Cranial Nerve Function Each cranial nerve carries out specific functions. Testing for a deficiency of a cranial nerves' function can give a clinician an idea of where the problem is located in a person’s brain.

Common Cranial Nerve Conditions Bell’s Palsy results from damage to the seventh cranial nerve or facial nerve. Bell's palsy is characterized by a one sided facial droop that comes on within 72 hours

Common Cranial Nerve Conditions Trigeminal neuralgia is a condition involving intense pain in the area innervated by the Trigeminal or fifth cranial nerve.