The Cranial Nerves

山东大学医学院 解剖教研室李振华

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

Functional components General somatic afferent fibers (GSA): transmit exteroceptive an

d 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

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: contain only afferent (sensory) fibers

ⅠOlfactory nerve ⅡOptic nerve Ⅷ Vestibulocochlear nerve

Motor cranial nerves: contain only efferent (motor) fibers Ⅲ Oculomotor nerve Ⅳ Trochlear nerve ⅥAbducent nerve Ⅺ Accessory nerv Ⅻ Hypoglossal nerve

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

Sensory cranial nervesN. 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

Olfactory nerve

Olfactory mucosa (SVA)→ Cribriform foramina → Olfactory bulb

Optic nerveGanglion cell (SSA) → Optic canal → Lateral geniculate body

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

Motor cranial nervesN. Nucleus of origin and

axon categoriesCranial exit Main action

Ⅲ Nucleus of oculomotor (GSE)

Superior orbital fissure

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

Accessory nucleus of oculomotor (GVE)

Parasympathetic to sphincter pupillea and ciliary muscl

Ⅳ Nucleus of trochlear nerve (GSE)

Superior orbital fissure

Motor to superior obliquus

Ⅵ Nucleus of abducent nerve (GSE)

Superior orbital fissure

Motor to lateral rectus

Ⅺ Nucleus of accessory nerve (SVE)

Jugular foramen Motor to sternocleidomastoid and trapezius

Ⅻ Nucleus of hypoglossal nerve( GSE)

Hypoglossal canal Motot to muscles of tongue

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 superi

oris Sphincter pupillea and ciliary muscle

Ciliary ganglion: lies between optic nerve and lateral rectus

Oculomotor nerve

Abducent nerve

Accessory nerve

Hypoglossal nerve

Hypoglossal nerve

Oculamotor paralysis

Abducent nerve injury

Mixed cranial nerves

Trigeminal nerve

Components of fibers SVE fibers: originate from motor nucleus of trige

minal 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

Branches Ophthalmic nerve

眼神经 ( 1, sensory) Ⅴleave the skull through the superior orbital fissure, to enter orbital cavity

Branches Frontal nerve 额神经 :

Supratrochlear nerve 滑车上神经

Supraorbital nerve 眶上神经

Lacrimal nerve 泪腺神经

Nasociliary nerve 鼻睫神经

Distribution: Sensation from cerebra

l dura mater Visual organ Mucosa of nose Skin above the eye and

back of nose

Maxillary nerve 上颌神经 ( 2, sensory)Ⅴ

Leave skull through foramen rotundum

Branches Infraorbital nerve 眶

下神经 Zygomatic nerve

颧神经 Superior alveolar nerv

e 上牙槽神经 Pterygopalatine nerve

翼腭神经

Distribution: Sensation from cerebral

dura mater Maxillary teeth Mucosa of nose and mo

uth Skin between eye and m

outh

Mandibular nerve ( 3, mixeⅤd) 下颌神经

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

Branches Auriculotemporal nerve

耳颞神经 Buccal nerve 颊神经 Lingual nerve 舌神经 Inferior alveolar nerve 下牙槽神

经 Nerve of masticatory muscles

咀嚼肌神经

Distribution: Sensation from cerebral du

ra mater Teeth and gum of lower jaw Mucosa of floor of mouth Anterior 2/3 of tongue Skin of auricular and tempor

al regions and below the mouth

Motor to masticatory muscles, mylohyoid, and anterior belly of digastric

Facial nerve (Ⅶ)Components of fibers SVE fibers originate from nucleus of facial nerve, and supply faci

al muscles

GVE fibers derived from superior salivatory nucleus and relayed i

n pterygopalatine ganglion and submandibular ganglion. The pos

tganglionic fibers supply lacrimal, submandibular and sublingual

glands

SVA fiber from taste buds of anterior two-thirds of tongue which

cell bodies are in the geniculate ganglion of the facial nerve and

end by synapsing with cells of nucleus of solitary tract

GSA fibers from skin of external ear

Course: leaves skull throu

gh internal acoustic mea

tus, facial canal and styl

omastoid foramen, it the

n enters parotid gland w

here it divides into five br

anches which supply faci

al muscles

Branches within the facial canal Chorda tympani 鼓索 : joins lingual branch of mandibular nerve

To taste buds on anterior two-thirds of tongue

Relayed in submandibular ganglion, the postganglionic fibers supply subman

dibular and sublingual glands

Greater petrosal nerve 岩大神经 : GVE fibers pass to pterygopalatine g

anglion 翼腭神经节 and there relayed through the zygomatic and lacrimal

nerves to lacrimal gland

Stapedial nerve 镫骨肌神经 : to stapedius

Branches outside of facial canal Temporal Zygomatic Buccal Marginal mandibular Cervical

Pterygopalatine ganglion 翼腭神经节 : lies in pterygopalatine fossa under maxillary nerve

Submandibular ganglion 下颌下神经节 : lies between lingual nerve and submandibular gland

Injury to the facial nerve

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

opharygeus GVE fibers: arise from inferior salivatory nucleus and ralyed i

n otic ganglion, the postganglionic fibers supply parotid gland SVA fibers: arise from the cells of inferior ganglion, the centr

al processes of these cells terminate in nucleus of solitary tract, the peripheral processes supply the taste buds on posterior third of tongue

GVA fibers: visceral sensation from mucosa of posterior third of tongue, pharynx, auditory tube and tympanic cavity, carotid sinus and glomus, and end by synapsing with cells of nucleus of solitary tract

GSA fibers: sensation from skin of posterior surface of auricle and

Course: leaves the skull via jugular foramen

Branches Lingual branches 舌支 : to taste buds and mucosa of posterior thir

d of tongue Pharyngeal branches 咽支 : take part in forming the pharyngeal plex

us Tympanic nerve 鼓室神经 : GVE fibers via tympanic and lesser petro

sal nerves to otic ganglion, with postganglionic fibers via auriculotemporal ( 3) to parotid glandⅤ

Carotid sinus branch 颈动脉窦支 : innervations to both carotid sinus and glomus

Others: tonsillar and stylophayngeal branches

Otic ganglion 耳神经节 : situated just below foramen ovale

Vagus nerve (Ⅹ)components of fibers GVE fibers: originate from dorsal nucleus of vagu

s 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: carry impulse from viscera in neck, thoracic and abdominal cavity to nucleus of solitary tract

GSA fiber: sensation from auricle, external acoustic meatus and cerebral dura mater

Course Exits the skull from jugular foramen Descends in the neck in carotid sheath between int

ernal (or common) carotid artery and internal jugular vein

Right vagus nerve Enter thoracic inlet on right side of trachea Travels downward posterior to right brachiocephali

c vein and superior vena cava Passes posterior to right lung root Forms posterior esophageal plexus Forms posterior vagal trunk at esophageal hiatus w

here it leaves thorax and passes into abdominal cavity, then divides into posterior gastric and celiac branches

Left vagus nerve Enter thoracic inlet between left common caroti

d and left subclavian arteries, posterior to left brachiocephalic vein

Crosses aortic arch where left recurrent laryngeal nerve branches off

Passes posterior to left lung root 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

Branches in neck Superior laryngeal nerve: passes down s

ide of pharynx and given rise to Internal branch, which pierces thyrohyoid mem

brane 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 mening

eal branches

Superior laryngeal nerve

External branch

Internal branch

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 joint, the nerve is now called inferior laryngeal nerve

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

Bronchial and esophageal branches

Branches in abdomen Anterior and posterior gastric

branches Run close to lesser curvature an

d innervate anterior and posterior surfaces of stomach

As far as pyloric antrum to fan out into branches in a way like the digits of a crow’s foot to supply pyloric part

Hepatic branches: join hepatic plexus and then supply liver and gallbladder

Celiac branches: send branches to celiac plexus to be distributed with sympathetic fibers to liver, pancreas, spleen, kidneys, intestine as far as left colic flexure