Branches (or peripheral & central processes)

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Nerve / fiber type

Cell body of origin


(or peripheral & central processes)

Travels through


I Olfactory


Dispersed collections of neurons located in olfactory mucosa in root of nasal cavity

Peripheral processes: surface of olfactory mucosa
Central processes: terminate in olfactory bulb.

Central processes pass thru cribiform plate in ethmoid bone.
Olfactory bulb axons form olfactory tract (CNS) to terminate in cortex.

-visceral olfactory responses sensed by nose

II Optic


Dispersed ganglion cells within the retina as the ganglion cell layer

Peripheral processes: part of the ganglion cell that connects to bipolar cells.
Central processes: optic nerve

Light in retina: rods & cones > bipolar cells to peripheral processes around ganglion cells.
Optic nerves pass through the optic canal.

Nasal fibers cross to contralateral side: optic chiasm. Lateral side remains uncrossed. These travel through optic tracts.

-coordinated visual fields

III Oculomotor




Oculomotor nucleus


1˚- Accessory oculomotor nucleus (Edinger-westphal nucleus).

2˚- ciliary ganglion

Superior division

Inferior division

Travels thru the superior orbital fissure.
Parasympathetic travels along with the inferior division.

Superior division:

-superior rectus

-levator palpebra superiorus

Inferior division:

-medial rectus

-inferior rectus

-inferior oblique

IV Trochlear


Trochlear nucleus

Travels thru the superior orbital fissure.

Superior oblique

V Trigeminal

-somatosensory (90%)

-somatomotor (10%)


Trigeminal (sensory) ganglion

Somatomotor: trigeminal motor nucleus.

Peripheral processes are in skin (V1-V3).

Central processes terminate in trigeminal spinal nucleus.

V1 – ophthalmic

-frontal nerve

-lacrimal nerve

-nasociliary nerve

V2 – maxillary

-infraorbital nerve

-greater & lesser palatine nerves

-zygomatic nerve

-posterior superior alveolar nerve

-sphenopalatine nerve

V3 – mandibular


-inferior alveolar neve

-lingual nerve

-buccal nerve

-auriculotemporal nerve


V1 ophthalmic goes thru the superior orbital fissure.

-frontal nerve into forehead

-lacrimal nerve into lateral side of eye

-nasociliary nerve into eye and nose

V2 maxillary travels thru foramen rotundum.

V3 mandibular travels thru foramen ovale into mandible.

V1 – forehead to corners of eyes
V2 – between corners of eyes to corners of mouth.

Maxillary sinus & upper teeth.

V3 – (sensory) mandible & lower teeth, gen. sensation to tongue, cheeks, ear, side of head.

(motor) masseter, temporalis, medial pterygoid, lateral pterygoid

mylohyoid, anterior belly of digastric, tensor tympani & tensor veli palatini.

VI Abducens Nerve


Abducens nucleus

Travels thru the superior orbital fissure to the lateral side of the orbit.

Lateral rectus

VII Facial Nerve





Facial nucleus


Geniculate ganglion


Superior salivary nucleus








Peripheral are taste receptors on anterior 2/3 of tongue, external ear.

Central processes terminate in nucleus solitarius (taste) and spinal trigeminal nucleus (external ear).

1˚ - superior salivary nucleus.

Greater petrosal nerve contains preganglionic parasympathetic.

2˚ - pterygopalatine ganglion.

Chorda tympani contains preganglionic parasympathetic & taste fibers to anterior tongue from geniculate ganglion.

2˚ - submandibular ganglion.

Leave cranial cavity thru internal auditory meatus. Travels thru the facial canal in the temporal bone.

Exits thru stylomastoid foramen.

Somatomotor & somatosensory:

Travel thru internal auditory meatus, facial canal, and stylomastoid foramen. Primarily somatomotor.


Greater petrosal nerve thru facial canal, thru geniculate ganglion to pterygopalatine ganglion.

Chorda tympani travel thru facial canal, then leave thru tympanic cavity (middle ear).

Somatomotor: muscles of facial expression

Stylohyoid, stapedius, posterior belly of digastric.

Somatosensory: external ear and taste receptors in tongue.
Visceromotor: lacrimal gland, submandibular gland, sublingual gland, mucous gland, oral mucous glands.

VIII Vestibulocochlear


Vestibular ganglion (balance)

Spiral ganglion (cochlear)

Peripheral process: sensory cells of vestibular/cochlear region.

Central processes terminate in vestibular nuclei (vestibular) or cochlear nuclei (cochlear).

Vestibular ganglion travel thru semicircular canals
Cochlear ganglion are around turns of cochlea.
Travel thru internal auditory meatus.

Inner ear

IX Glossopharyngeal

-somatosensory 90%



Somatomotor: nucleus ambiguous

Inferior ganglion of the glossopharyngeal nerve


1˚ - inferior salivary nucleus

2˚ - otic ganglion

Peripheral processes carry:

-taste & somatosensory information from posterior 1/3 of tongue

-somatosensory information from pharynx

-somatosensory information from middle ear, auditory tube, mastoid air cells

-viscerosensory information from carotid body: baroreceptors & chemoreceptors
Central processes terminate in nucleus solitarius – taste, baroreceptors & chemoreceptors

Spinal trigeminal nucleus – general sensory.

Travels thru jugular foramen.

Posterior third of tongue, mucosa of pharynx, middle ear, auditory tube, blood pressure & chemoreceptors near common carotid.
Somatomotor: stylopharyngeus muscle
Visceromotor: parotid gland

X Vagus





Nucleus ambiguous


Inferior ganglion of the vagus nerve (nodose ganglion).

Superior ganglion terminate in the spinal trigeminal nucleus of brainstem.

1˚ - dorsal motor nucleus of the vagus

2˚ -

Peripheral process: in mucosa of larynx, respiratory system, heart, digestive system.

In external auditory meatus, meninges of posteriocranial fossa, external surface of tympanic membrane.

Central processes: -terminate in nucleus solitarius.

-termiante in spinal trigeminal nucleus.

Travels thru the jugular foramen.

Somatomotor: larynx, pharynx, and soft palate muscles: pharyngeal constrictor muscles, muscles of larynx, levator veli palatini, palatoglossus, palatopharyngeus, salpingopharyngeus
Somatosensory: laryngeal mucosa, meninges of posterior cranial fossa, external ear
Parasympathetic: smooth & cardiac muscles of thorax, smooth muscle of abdomen up to splenic flexure.

XI Accessory



Ascend in vertebral canal, travel thru foramen magnum to cranial cavity, then travel back out thru jugular foramen.



XII Hypoglossal


Hypoglossal nucleus

Exits cranial cavity through hypoglossal canal of occipital bone

Intrinsic muscles of tongue




  • Somatomotor come from somatomotor nuclei in brainstem.

  • Somatosensory go to cranial nerve sensory ganglia outside the brain: these have peripheral and central processes. Receptors are near peripheral processes, central processes terminate in a cranial nerve sensory nucleus.

  • Autonomic fibers have a two-cell chain

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