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

Fiber components of cranial n.

General somatic afferent(sensory) fibers 一 : transmit exteroceptive and proprioceptive impulses from head and face to somatic sensory nuclei of the brain stem;

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

Fiber components of cranial n.

General visceral afferent (sensory) fibers transmit interoceptive impulses from the viscera to the visceral sensory nuclei-nucleus of solitery tract;

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

Fiber components of cranial n.

General somatic afferent (motor) fibers : arises from the General somatic motor nuclei and innervate skeletal muscles of eye and tongue.

Special visceral afferent (motor) fibers : arises from the Special visceral motor nuclei in the brain and to skeletal muscles derived from gill arches () of embryo ： such as the m. of mastication, facial expression and swallowing.

Fiber components of cranial n.

General visceral afferent (motor) fibers : arise from the general visceral motor nuclei and relayed in parasympathetic ganglions,e postganglionic fibers supply cardiac muscles ， smooth muscles and glands.

Classification of cranial nerves

Sensory cranial nerves : contain only sensory fibers

Ⅰ. Olfactory nerve

Ⅱ. Optic nerve

Ⅷ. Vestibulocochlear nerve

Classification of cranial nerves

Motor cranial nerves : contain only motor fibers

Ⅲ. Oculomotor nerve

Ⅳ. Trochlear nerve

Ⅵ. Abducent nerve

Ⅺ. Accessory nerve

Ⅻ. Hypoglossal nerve

Classification of cranial nerves

Mixed nerves : contain both sensory and motor fibers

Ⅴ. Trigeminal nerve

Ⅶ. Facial nerve

Ⅸ. Glossopharyngeal nerve

Ⅹ. Vagus nerve

Sensory cranial nerves

I ． Olfactory nerve II. Optic nerveVIII.Vestibulocochlear nerve

Olfactory nerve

Olfactory cell → Olfactory nerve → Cribriform foramina

→ Olfactory bulb

Olfactory nerve

Function: conduct the smell

Optic nerve

Ganglion cell of retina → Optic nerve → Optic canal →

optic chiasma→optic tract → lateral geniculate body.

Vestibulocochlear nerve

Cochlear ganglion

Vestibular ganglionInternal acoustic meatus

Vestibular nuclei

Cochlear nucleiVestibulocochlear nerve

Sensory cranial nerves

N. Location of cell body

Cranial exit

Terminal nuclei

Main action

Ⅰ Olfactory cellsCribrifomforamina

Olfactory bulb

Smell

Ⅱ Ganglion cells of retina

Optic canal

Lateral geniculate body

Vision

Ⅷ

Vestibular ganglion of internal ear

Internal acoustic meatus

Vestibular nuclei

Equilibrium

Cochlear ganglionof internal ear

Cochlear nuclei

Hearing

Motor cranial nerves

III.Oculomotor nerve

IV. trochlear nerve V. VI. Abducent nerve

XI. accessory nerve

XII. hypoglossal nerve

Oculomotor nerve

supplies : Superior, inferior and medial recti; inferior obliquus; levator palpebrae superioris

Sphincter pupillae and ciliary muscleNucleus of oculomotor n.

Accessory nucleus of oculomotor n.

ComponentsGeneral somatic motor （ efferent ） fiber arises from nucleus occulomotorGeneral visceral motor （ efferent ） fiber arises from accessory nucleus of Ⅲ

Oculomotor nerve

Oculomotor nerve

Course:

•Leave the brain at the interpeduncular fossa;

•Pass through the lateral wall of cavernous sinus

•Via superior orbital fissure enter the orbita

Oculamotor paralysis

The injury of the oculomotor n. may lead to:

Droping of the upper eyelid;

lateral strabismus ;

Dilation of the pupil;

The pupillary reflexes disappear

trochlear nerve

Trochlear n. arises from the nucleus of trochlear nerve,

and pass through the superior orbital fissure to supply the superior obliquus

Abducent nerve

abducent n. arises from the nucleus of abducent nerve, and pass through the superior orbital fissure to supply the lateral rectus

Accessory nerve

Accessory nerve

Cranial root ： arises from nucleus ambiguus;Spinal root arises from the accessory nucleus pass through jugular foramen,and supplies 2 muscles

sternocleidomastoid

trapezius

Hypoglossal nerve

Hypoglossal nerve

Nucleus of hypoglossal nerve

Hypoglossal canal

Function of Cranial Nerve 12

supplies the intrinsic and extrinsic muscles of the Tongue genioglossus

extend the tongue with Contraction

So what happens if the CN12 has been

damaged ?

Motor cranial nerves

N. Nucleus of origin Cranial exit supply

Ⅲ

Nucleus of oculomotorSuperior orbital fissure

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

Accessory nucleus of oculomotor (Parasympathetic )

sphincter pupillea and ciliary muscl

Ⅳ Nucleus of trochlear nerve

Superior orbital fissure

superior obliquus

Ⅵ Nucleus of abducent nerve

Superior orbital fissure

lateral rectus

ⅪNucleus of accessory nerve

Jugular foramen sternocleidomastoid and trapezius

ⅫNucleus of hypoglossal nerve

Hypoglossal canal muscles of tongue

Mixed cranial nerves

V. Trigeminal nerveVII.Facial nerveIX. Glossopharyngeal nerveX. Vagus nerve

Trigeminal nerve

Components of fibers

General somatic afferent fibers: transmit facial sensation to sensory nuclei of trigeminal nerve, the fibers have their cell bodies in trigeminal ganglion,

Special viceral efferent fibers: originate from motor nucleus of trigeminal nerve, and supply masticatory muscles

Branches

Frontal nerve : Supratrochlear nerve

Supraorbital nerve

Branches

Ophthalmic nerve (Ⅴ1, sensory)

leave the skull through the superior

orbital fissure, to enter orbital cavity

Lacrimal nerve :→lacrimal gland Nasociliary nerve ; → eyeball

Distribution:

Visual organ Part of mucosa of nose Skin above the palpebral fisure and back of nose cerebral dura mater

Infraorbital nerve Zygomatic nerve Superior alveolar ner

ve Pterygopalatine nerve

Maxillary nerve ( 2, sensory)Ⅴ

Leave skull through foramen rotundum

Branches

Distribution:

Maxillary teeth

Mucosa of nose and mouth

Skin between the palpebral fissure and oral fissure.

cerebral dura mater

Auriculotemporal nerve Buccal nerve Lingual nerve Inferior alveolar nerve

Nerve of masticatory muscles

Mandibular nerve (Ⅴ3, mixed)

Leave the skull through the foramen ovale 卵圆孔 to enter the infratemporal fossa

Branches

Distribution:

cerebral dura mater;

Mandibular teeth and gum;

Mucosa of floor of mouth

Anterior 2/3 of tongue;

Skin of auricular and temporal regions and below the oral fissure;

masticatory muscles, mylohyoid, and anterior belly of digastric m.

Facial nerve (Ⅶ)

Components of fibers

Special visceral efferent fiber: fibers originate from nucle

us of facial nerve, and supply facial muscles.

General visceral efferent fiber: fibers arise from superior

salivatory nucleus and relayed in pterygopalatine gangli

on and submandibular ganglion. The postganglionic fibe

rs supply lacrimal, submandibular and sublingual glands.

Facial nerve (Ⅶ)

Components of fibers.

Special visceral afferent fiber: fiber from taste buds of ant

erior 2/3 of tongue which cell bodies are in the geniculate g

anglion of the facial nerve and end the nucleus of solita

ry tract.

General somatic afferent fiber: fibers distribute the skin of

external ear.

Course: leaves skull through internal acoustic meatus, facial canal and stylomastoid foramen, it then enters parotid gland where it divides into five Branches which supply facial Muscles.

Chorda tympani : joins lingual branch of mandibular nerve

To taste buds on anterior two-thirds of tongue.

Relayed in submandibular ganglionthe postganglionic fibers sup

ply submandibular and sublingual glands

Branches within the facial canal

Greater petrosal nerve : fibers pass to pterygopalatine gangli

on and the postganglionic fibers through the zygomatic and lacrim

al nerves to lacrimal gland

Stapedial nerve to stapedius

Temporal branch

Zygomatic branch

Buccal branch

Marginal mandibular branch

Cervical branch

Branches outside of facial canal

Pterygopalatine ganglion : lies in pterygopalatine fossa under maxillary nerve

Submandibular ganglion : lies between lingual nerve and submandibular gland

Injury to the facial nerve

？2. How to distinguish the supranuclear paralysis and infranuclear paralysis

1. Is this paralysis belong to supranuclear paralysis and infranuclear paralysis

Glossopharyngeal nerve ( )Ⅸ

Special visceral efferent fiber: originate from nucleus ambiguus, and supply stylopharygeus.

general visceral efferent fiber: arise from inferior salivatory nucleus and ralyed in otic ganglion, the postganglionic fibers supply parotid gland.

Special visceral afferent fiber: transmit the taste of posterior third of tongue to the nucleus of solitary tract.

Components of fibers

Glossopharyngeal nerve ( )Ⅸ

general visceral afferent fiber: transmit the visceral sensation from mucosa of posterior third of tongue, pharynx, auditory tube and tympanic cavity, carotid sinus and glomus, to the nucleus of solitary tract.

general somatic afferent fiber: conduct the sensation from skin of posterior surface of auricle.

Components of fibers

Branches

Lingual branches : to taste buds and mucosa of posterior third of tongue

Pharyngeal branches : take part in forming the pharyngeal plexus

Tympanic nerve : → tympanic cavity and auditory tube, and its general visceral motor fibers via lesser petrosal nerves to end the otic ganglion, the postganglionic fibers via auriculotemporal n.( 3) to Ⅴ parotid gland

Course: leaves the skull via jugular foramen

Carotid sinus branch : →carotid sinus and glomus

Others: tonsillar and stylophayngeal branches

Otic ganglion : situated just below foramen ovale

Branches

Lingual branches

Carotid sinus branch

Pharyngeal branches

Vagus nerve (Ⅹ)

general visceral efferent fiber: originate from dorsal nucleus of vagus nerve, synapse in parasympathetic ganglion, short postganglionic fibers innervate cardiac muscles, smooth muscles and glands of viscera

Special visceral efferent fiber: originate from the nucleus ambiguus, to muscles of pharynx and larynx

components of fibers

Vagus nerve (Ⅹ)

general visceral afferent fiber: carry impulse from viscera in neck, thoracic and abdominal cavity to nucleus of solitary tract

general somatic afferent fiber: conduct the sensation from auricle, external acoustic meatus and cerebral dura mater to the spinal nucleus of trigeminal n.

components of fibers

Right vagus nerve Enter thoracic cavity on right side of trachea and infront of right subclavian a. and passes posterior to right lung root

Forms posterior esophageal plexus

and posterior vagal trunk

Passes though the esophageal hiatus into abdominal cavity, then divides into posterior gastric 胃后支 and celiac branches 腹腔支

Course•Exits the skull from jugular foramen

•Descends in the neck in carotid sheath between internal (or common) carotid artery and internal jugular vein

Left vagus nerveEnter thoracic cavity between left common carotid and left subclavian arteries, Descends infront of the aortic arch

Passes posterior to the root of left lung Forms anterior esophageal plexus and anterior vagal trunk

Passes though the esophageal hiatus

into abdominal cavity, and divides into anterior gastric and hepatic branches.

External branch

Internal branch which pierces thyrohyoid

membrane to innervates mucous membrane of larynx above fissure of glottis

External branch, which innervates cricothyroid

Branches in neck

Superior laryngeal nerve

Internal branch

Cervical cardiac branches descending to terminate in cardiac plexus

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 cric

othyroid joint, the nerve is now called inferior laryngeal nerve

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

Branches in thorax

Bronchial and esophageal branches

Anterior and posterior gastric branches Run close to lesser curvature and

innervate anterior and posterior surfaces of stomach

Branches in abdomen

Celiac branches:

send branches to celiac plexus whose fibers distribute with sympathetic fibers to liver, pancreas, spleen, kidneys, intestine as far as left colic flexure

Hepatic branches : supply liver and gallbladder

Nucleus of oculomotor n.

Accessory nucleus of oculomotor n.

Inferior alveolar nerve

Auriculotemporal nerve

The nerve distribution of tongue 舌的神经分布

• Hypoglossal n. → the musels of tongue;

• Mandibular n. → anterior 2/3 mucosa of tongue;

• Facial n. → anterior 2/3 teste buds of tongue;

• Glossopharygeal n. →the mucosa and teste

buds of the root of tongue

The nerve distribution of the eyeball?III →sup. Inferior and medial rectus,inferior obliquus IV→ superior obliquus VI→lateral rectusOptic n. → visual sense;Ophthalmic n. →general sense of eyeball;sympathetic n. →dilator pupillae;parasympathetic n. →sphincter pupillae and ciliary m.