The Cranial Nerves

The Cranial Nerves

SHANDONG UNIVERSITY

Liu Zhiyu

Names of Cranial Nerves Ⅰ Olfactory nerve Ⅱ Optic nerve Ⅲ Oculomotor nerve Ⅳ Trochlear nerve Ⅴ Trigeminal nerve Ⅵ Abducent nerve Ⅶ Facial nerve Ⅷ Vestibulocochlear nerve Ⅸ Glossopharyngeal nerve Ⅹ Vagus nerve Ⅺ Accessory nerve Ⅻ Hypoglossal nerve

I Olfactory (oh)

II Optic (oh)

III Oculomotor (oh)

IV Trochlear (to)

V Trigeminal (1-3) (touch)

VI Abducens (and)

VII Facial (feel)

VIII Vestibulocochlear (very)

IX Glossopharyngeal (good)

X Vagus (velvet)

XI Accessory (ah)

XII Hypoglossal (heaven)

How to Remember CN I-XII

Oh! Oh! Oh! To Touch And Feel

Very Good Velvet! Ah Heaven!

Functional Components General somatic afferent fibers (GSA): transmit ext

eroceptive and proprioceptive impulses from head and face to somatic sensory nuclei

Special somatic afferent fibers (SSA): transmit sensory impulses from special sense organs of vision, equilibrium and hearing to the brain

General visceral afferent fibers (GVA): transmit interoceptive impulses from the viscera to the visceral sensory nuclei

Special visceral afferent fibers (SVA): transmit sensory impulses from special sense organs of smell and taste to the brain

Functional Components

General somatic efferent fibers (GSE): innervate skeletal muscles of eye and tongue

Special visceral efferent fibers (SVE): transmit motor impulses from the brain to skeletal muscles derived from brachial (gill) arches of embryo. These include the muscles of mastication, facial expression and swallowing

General visceral efferent fibers (GVE): transmit motor impulses from the general visceral motor nuclei and relayed in parasympathetic ganglions. The postganglionic fibers supply cardiac muscles， smooth muscles and glands

Classification of Cranial Nerves Sensory cranial nerves: are composed entirely of afferent (sens

ory) nerve fibers bringing sensations the brain Ⅰ Olfactory nerve Ⅱ Optic nerve Ⅷ Vestibulocochlear nerve

Motor cranial nerves: are composed entirely of efferent (motor) fibers Ⅲ Oculomotor nerve Ⅳ Trochlear nerve Ⅵ Abducent nerve Ⅺ Accessory nerve Ⅻ Hypoglossal nerve

Mixed cranial nerves: possess both sensory and motor fibers--- Ⅴ Trigeminal nerve, Ⅶ Facial nerve, Ⅸ Glossopharyngeal nerve Ⅹ Vagus nerve

Olfactory Nerve

Olfactory Nerve

Olfactory cells (SVA)→ Cribriform foramina → Olfactory bulb

Optic NerveGanglion cells (SSA) → Optic canal → Lateral geniculate body

Vestibulocochlear Nerve

Vestibular ganglion(SSA) ↘ ↗ Vestibular nuclei Internal acoustic meatus Cochlear ganglion (SSA) ↗ ↘ Cochlear nuclei

Sensory Cranial Nerves

N. Location of cell body and axon categories

Cranial exit

Terminal nuclei

Main action

Ⅰ Olfactory cells (SVA)

Cribrifomforamina

Olfactory bulb Smell

Ⅱ Ganglion cells (SSA)

Optic canal

Lateral geniculate body

Vision

Ⅷ Vestibular ganglion(SSA)

Internal acoustic meatus

Vestibular nuclei

Equilibrium

Cochlear ganglion (SSA)

Cochlear nuclei Hearing

Ⅲ

Ⅳ

Ⅵ

Ⅻ

Ⅺ

Superior orbital fissure

Hypoglossal canal

Jugular foramen

Ⅹ

Motor Cranial Nerves

Oculomotor Nerve Components

General somatic efferent fibers (GSE) General visceral efferent fibers (GVE)

Main action－ supplies Superior, inferior and medial recti; inferior obliquus; levator palpebrae su

perioris Sphincter pupillea and ciliary muscle

Ciliary ganglion : lies between optic nerve and lateral rectus

Oculomotor nerve

Abducent Nerve

Abducent nerve

Oculomotor n.

Trochlear n.

Abducent n.

Accessory Nerve

Cranial roots Originate from nucleus ambiguus Join the spinal roots to exit the jug

ular foramen Join the vagus nerve and distribute

to the muscles of pharynx and larynx

Spinal roots Originate from nucleus of accessor

y nerve Ascend through the foramen magn

um and exit the cranium through the jugular foramen

Innervate the sternocleidomastoid and trapezius muscles

Hypoglossal Nerve

Hypoglossal nerve

Nucleus of hypoglossal nerve( GSE)

→ →Hypoglossal canal Muscles of tongue

Motor Cranial NervesN. Nucleus of origin and

axon categoriesCranial exit Main action

Ⅲ Nucleus of oculomotor nerve (GSE)


Motot to superior, inferior and medial recti; inferior obliquus; levator palpebrae superioris

Accessory nucleus of oculomotor nerve (GVE)

Parasympathetic to sphincter pupillea and ciliary muscles

Ⅳ Nucleus of trochlear nerve (GSE)


Motor to superior obliquus

Ⅵ Nucleus of abducent nerve (GSE)


Motor to lateral rectus

Ⅺ Nucleus ambiguus (cranial root, SVE)Nucleus of accessory nerve (spinal root, SVE)

Jugular foramen

Motor to sternocleidomastoid and trapezius

Ⅻ Nucleus of hypoglossal nerve( GSE)

Hypoglossal canal

Motot to muscles of tongue

Mixed Cranial Nerves

Trigeminal Nerve ( )Ⅴ

Components of fibers SVE fibers: originate from mot

or nucleus of trigeminal nerve, and supply masticatory muscles

GSA fibers: transmit facial sensation to sensory nuclei of trigeminal nerve, the GSA fibers have their cell bodies in trigeminal ganglion, which lies on the apex of petrous part of temporal bone

Trigeminal Nerve ( )ⅤOphthalmic nerve ( 1, sensory)Ⅴ Leave the skull through the superior orbital fis

sure, to enter orbital cavity Branches

Frontal nerve Supratrochlear nerve Supraorbital nerve

Lacrimal nerve Nasociliary nerve

Trigeminal Nerve ( )ⅤOphthalmic nerve Branches

Frontal nerve Lacrimal nerve Nasociliary nerve

Distribution Sensation from cerebral dura mater Visual organ Mucosa of nose Skin above the eye and back of nose


Maxillary nerve ( 2, sensory)Ⅴ Leave skull through foramen rotundum Branches

Infraorbital nerve Superior alveolar nerve Zygomatic nerve Pterygopalatine nerve


Maxillary nerve Branches

Infraorbital nerve Superior alveolar nerve Zygomatic nerve Pterygopalatine nerve

Distribution Sensation from cerebral dura mater Maxillary teeth and gum Mucosa of nose, mouth and maxillary sin

us Skin between eye and mouth


Mandibular nerve ( 3, mixed)Ⅴ Leave the skull through the foramen ovale

to enter the infratemporal fossa Branches

Auriculotemporal nerve Buccal nerve Lingual nerve Inferior alveolar nerve Nerve of masticatory muscles


Mandibular nerve Distribution

Sensation from cerebral dura mater Teeth and gum of lower jaw Mucosa of anterior 2/3 of tongue and

floor of mouth Skin of auricular and temporal region

s and below the mouth Motor to masticatory muscles, myloh

yoid, and anterior belly of digastric

Facial Nerve ( )Ⅶ

Components of fibers SVE fibers originate from nucleus of facial nerve, and supply facial

muscles

GVE fibers derived from superior salivatory nucleus and relayed in p

terygopalatine ganglion and submandibular ganglion. The postgangl

ionic fibers supply lacrimal, submandibular and sublingual glands

SVA fibers from taste buds of anterior two-thirds of tongue which cel

l bodies are in the geniculate ganglion and end by synapsing with ce

lls of nucleus of solitary tract

GSA fibers from skin of external ear

Facial Nerve ( )Ⅶ

Course: Exits the brain stem through th

e bulbopontine sulcus

Leaves the skull through intern

al acoustic meatus, facial cana

l and stylomastoid foramen, it t

hen enters parotid gland where

it divides into five branches whi

ch supply facial muscles

Facial Nerve ( )Ⅶ

Branches within the facial canal Chorda tympani: joins lingual branch

of mandibular nerve

SVA fiber to taste buds on anterior

two-thirds of tongue

GVE fibers relayed in submandibu

lar ganglion, the postganglionic fib

ers supply submandibular and subl

ingual glands

Facial Nerve ( )Ⅶ Greater petrosal nerve : GVE fibers pass to pterygopalatine ganglion a

nd there relayed through the zygomatic and lacrimal nerves to lacrimal gland

Stapedial nerve : to stapedius

Pterygopalatine ganglion

Facial Nerve ( )Ⅶ

Pterygopalatine ganglion: lies in pterygopalatine fossa under maxillary nerve

Submandibular ganglion: lies between lingual nerve and submandibular gland

Facial Nerve ( )Ⅶ

Branches outside of facial canal Temporal Zygomatic Buccal Marginal mandibular Cervical

Glossopharyngeal Nerve ( )ⅨComponents of fibers SVE fibers: originate from nucleus ambiguus, and supply stylopharyge

us which elevates the pharynx during swallowing and talking GVE fibers: arise from inferior salivatory nucleus and relayed in otic g

anglion, the postganglionic fibers supply parotid gland GVA fibers: visceral sensation from mucosa of posterior third of tongu

e, pharynx, auditory tube and tympanic cavity, carotid sinus and glomus, and end by synapsing with caudal part of nucleus of solitary tract

SVA fibers: arise from the cells of inferior ganglion, the central processes of these cells terminate in rostral part of nucleus of solitary tract, the peripheral processes supply the taste buds on posterior third of tongue

GSA fibers: The cell bodies are located in the superior ganglion. The central process carry impulse from skin of posterior surface of auricle to spinal nucleus of trigeminal n.

Glossopharyngeal Nerve ( )Ⅸ Course: Exits the brain stem through the retroolivary sulcus leaves the skull via jugular foramen Branches

Lingual branches : to taste buds and mucosa of posterior third of tongue Pharyngeal branches : take part in forming the pharyngeal plexus， distrib

ute to the walls of pharynx Tympanic nerve: GVE fibers via tympanic and lesser petrosal nerves to otic

ganglion, with postganglionic fibers via auriculotemporal ( 3) to parotid glaⅤnd

Carotid sinus branch: innervations to both carotid sinus and carotid glomus

Others: tonsillar and stylophayngeal branches Otic ganglion: situated just below foramen ovale

Glossopharyngeal Nerve ( )Ⅸ

Vagus Nerve ( )ⅩComponents of fibers GVE fibers: originate from dorsal nucleus of vagus nerve, synapse in

parasympathetic ganglion, short postganglionic fibers innervate cardiac muscles, smooth muscles and glands of viscera

SVE fibers: originate from ambiguus, to muscles of pharynx and larynx

GVA fibers: The cell bodies are located in the inferior vagal ganglion. The central process carry impulse from viscera in neck, thoracic and ab

dominal cavity to nucleus of solitary tract GSA fibers: The cell bodies are located in the superior vagal ganglion.

The central process carry impulse from auricle, external acoustic meatus and cerebral dura mater to spinal nucleus of trigeminal n.

Left Vagus Nerve

Course Enter thoracic inlet between left common caroti

d and left subclavian arteries Crosses the left side of the aortic arch where le

ft recurrent laryngeal nerve branches off Passes posterior to left lung root contributing to

the pulmonary plexus Descends on the anterior surface of the esoph

agus and forms anterior esophageal plexus Forms anterior vagal trunk at esophageal hiatu

s where it leaves thorax and passes into abdominal cavity , then divides into anterior gastric and hepatic branches

Right Vagus Nerve

Course Travels downward anterior to the right subcla

vian artery and enter thoracic inlet on right side of trachea

Passes posterior to right lung root contributing to the pulmonary plexus

Then passes on to the posterior surface of esophagus and forms posterior esophageal plexus

Forms posterior vagal trunk at esophageal hiatus where it leaves thorax and passes into abdominal cavity, then divides into posterior gastric and celiac branches

Vagus Nerve ( )ⅩBranches in neck Superior laryngeal nerve : passes

down side of pharynx and given rise to Internal branch, which pierces t

hyrohyoid membrane to innervates mucous membrane of larynx above fissure of glottis

External branch, which innervates cricothyroid

Cervical cardiac branches : descending to terminate in cardiac plexus

Others: auricular, pharyngeal and meningeal branches

Vagus Nerve ( )Ⅹ

Superior laryngeal nerve

External branch

Internal branch

Vagus Nerve ( )Ⅹ

Branches in thorax Recurrent laryngeal nerves

Right one hooks around right subclavian artery, left one hooks aortic arch

Both ascend in tracheo-esophageal groove Nerves enter larynx posterior to cricothyroid joi

nt, the nerve is now called inferior laryngeal nerve

Innervations: laryngeal mucosa below fissure of glottis, all laryngeal muscles except cricothyroid

Bronchial and esophageal branches

Documents

The Cranial Nerves