The Cranial Nerves
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Transcript of 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)
Superior orbital fissure
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)
Superior orbital fissure
Motor to superior obliquus
Ⅵ Nucleus of abducent nerve (GSE)
Superior orbital fissure
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
Trigeminal Nerve ( )Ⅴ
Maxillary nerve ( 2, sensory)Ⅴ Leave skull through foramen rotundum Branches
Infraorbital nerve Superior alveolar nerve Zygomatic nerve Pterygopalatine nerve
Trigeminal Nerve ( )Ⅴ
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
Trigeminal Nerve ( )Ⅴ
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
Trigeminal Nerve ( )Ⅴ
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