The cranial nerve
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
2. The cranial nerves consist of 4 kinds of fibers:
•
somatic sensory fibers
•
visceral sensory fibers
•
somatic motor fibers
•
visceral motor fibers
3. 3 types:
•
Sensory (afferent) nerves: I、Ⅱ、Ⅷ
•
Motor (efferent) nerves: III、Ⅳ、Ⅵ、Ⅺ、Ⅻ
•
Mixed nerves: Ⅴ、Ⅶ、Ⅸ、Ⅹ
Ⅱ. The sensory nerves:
1. Olfactory nerve:
•
Visceral sensory fibers
•
Cell bodies are in nasal
Mucosa olfactory region
(on the superior
nasal concha and opposed
part of nasal septum)
•
Pierces through cribriform
foramina and ends in
olfactory bulb.
•
Conducts sense of smell.
Ⅱ. The sensory nerves:
2. Optic nerve
• somatic sensory fibers.
• The central processes of ganglion cells
of retina converge on optic disc, then
pierce the sclera and form optic nerve.
• passes through optic canal into middle
cranial fossa, then joints optic chiasma.
• conveys the sense of sight.
III Oculomotor nerve (external squint)
Contains special and general visceral motor fibers
• Enter orbit through the superior orbital fissure.
• The special visceral motor fibers supply the
extraocular muscles
except for the superior obliquus and lateral rectus
• The general visceral motor fibers innervate the
ciliary muscle and sphincter pupillae muscles
superior obliquus
Oculomotor nerve
The general somatic
motor fibers
diplopia
Trochlear n.
Abducent n.
ciliary muscle
The general visceral
motor fibers
sphincter pupillae
muscles

•
Trochlear nerve(CN IV)
passes into orbit through the superior orbital fissure.
• Supplies the superior obliquus
Trochlear nerve:
• Emerges from anterior medullary velum
just behind the inferior colliculus—winds
forward around cerebral peduncle—
traverses lateral wall of cavernous sinus
—passes into orbit through the superior
orbital fissure
• Supplies the superior oblique muscle.(diplopia )
V. Trigeminal nerve:
 It has a motor and a sensory
roots.The motor root contains
the somatic motor fibers arising
from the motor nucleus of trigeminal
nerve; Sensory root contains the
somatic sensory fibers which are
central processes of the neurons
located in the trigeminal ganglion.
 It’s formed by the peripheral processes of neurons of trigeminal
ganglion and few somatic motor fibers.
 3 divisions:
—ophthalmic nerve
—maxillary nerve
—mandibular nerve
 Ophthalmic nerve:
• a sensory nerve
• passes forwards along the lateral
wall of cavernous sinus—separated
into 3 branches—enter the orbit
through the superior orbital fissure :
 lacrimal nerve: lacrimal gland
 frontal nerve: divided into
supratrochlear n.
supraorbital nn.
which distributed to the skin
of forehead and anterior part
of scalp.
 nasociliary nerve: eyelid, nasoal
sinuses,skin and mucosa of nose.
 Maxillary nerve
• a sensory nerve.
• traverses the lateral wall of cavernous
sinus below the ophthalmic n.—
the foramen rotundum—crosses the
pterygopalatine fossa—enter the orbit
through the inferior orbital fissure
(infraorbital n.)—passes forwards
the infraorbital groove and canal—
appears on the face through infraorbital
foramen(supplies the ala of nose,lower
eyelid and upper lip)
• 3 branches:
--- zygomatic n.: skin of cheek and temple
--- pterygopalatine n.:
mucosa of nasal cavity,
palatine and pharynx
--- superior alveolar n:
maxillary sinus, upper gum
and teeth.
 Mandibular nerve:
• a mixed nerve
• through the foramen ovale.
• 5 branches:
---muscular branches: mastication.
---buccal n.: skin and mucosa of cheek
---lingual n.: mucosa of anterior
2/3 of tongue
---inferior alveolar n.:
mandibular foramen—mendibular
canal—mental foramen(mental n.)
* lower teeth and gum, skin and mucosa of lower lip.
** muscular branch(mylohyoid and anterior belly of digastric
mm.)
---auriculotemporal n.:
skin of anterior surface of auricle, temporal region, parotid gland.
Abducens
nerve(CN VI)
• enters the orbit through the superior orbital fissure.
•
Innervates the lateral rectus
VII。Facial nerve:
• contains 3 types of fibers:
--- somatic motor fibers:
arise from the facial nucleus
--- visceral motor fibers:
arise from the superior salivatory
nucleus.
--- visceral sensory fibers:
arise from the geniculate ganglion
and terminate in the nucleus of solitary tract.
• Emerges from the pontomedullary groove just medially to the
vestibulocochlear n.
• Passes into the internal acoustic meatus through the internal
acoustic pore—enter the facial canal—turns sharply backwards
and downwards—emerges through the stylomastoid foramen—
runs forward into the parotid gland—gives off 5 brabches.
• Branches outside the
facial canal:
--- temporal branch
--- zygomatic branches
--- buccal branches
--- mandibular branch
--- cervical branch
(contain the somatic
motor fibers –
mimetic muscles and
platysma)
• branches within the facial canal:
--- greater petrosal n.:
* formed by visceral motor fibers
(parasympathetic preganglionic
fibers)
* make relay in pterygopalatine
ganglion, postganglionic fibers
supply the lacrimal gland and
glands of nose and palate
• branches within the facial canal:
--- chorda tympanic:
•Arises from facial n. about 6mm
above the stylomastoid foramen
—enter the tympanic cavity—
pierces anteroinferior wall to
join the lingual n.
* The visceral sensory fibers
(mucous memberane of ant. 2/3
of tongue and responsible for taste)
* The visceral motor fibers pass into the submandibular ganglion
and make relay, the postganglionic fibers supply the
submandibular and sublingual glands.
VIII. Vestibulocochlear nerve:
• somatic sensory fibers
• consists of cochlear and vestibular
nerves.
• Cochlear nerve is formed by
central processes of bipolar cells of
cochlear ganglion in the central
modiolus of cochlea
• Vestibular nerve is formed by
central processes of cells of
vestibular ganglion.
•
• passes into brain stem through internal acoustic meatus.
• Conducts sense of hearing and balance.
IX. Glossopharyngeal nerve:
• contains 4 types of fibers
--- somatic motor fibers: arise from the nucleus ambiguus.
--- visceral motor fibers:arise from the inferior salivatory nucleus.
--- somatic sensory fibers: arise from the superior ganglion and
terminate in the spinal nucleus of trigeminal nerve.
--- visceral sensory fibers: arise from the inferior ganglion and
terminate in the nucleus of solitary tract.
• leaves the skull through the jugular foramen—passes forwards
between the internal carotid artery and internal jugular vein—
passes along the stylopharyngeus — enters the pharynx.
• main branches:
--- carotid sinus branch
(to the carotid glomus
and carotid sinus)
--- lingual branch
(to the vallate papillae
& mucous membrane
of the posterior 1/3 of
the tongue)
--- pharyngeal branches
(to the mucousmembrane of
pharynx and
--- tympanic nerve:
* arises from the inferior
ganglion of the nerve---ascends
to the tympanic cavity to forms
the typanic plexus---lesser
petrosal n.
* The lesser petrosal n. joints
the otic ganglion to make rely,
postganglionic fibers joint
the auriculotemporal n. and to
the parotid gland.
X. Vagus n.
• contains 4 kinds of fibers
---somatic motor fibers arising from the nucleus ambiguus.
---visceral motor fibers arising from the dorsal nucleus of vagus n.
---somatic sensory fibers arising from the superior ganglion of
vagus n. and stop to the spinal nucleus of trigeminal n.
---visceral sensory fibers arising from the inferior ganglion of the n.
and stop to the nucleus of solitary tract.
• It is attached to medulla oblongata.
• It leaves the skull through the
jugular foramen—passes down
in the carotid sheath behind the
internal jugular v. and internal
carotid a.—enters the thorax
between subclavian a. and v.
(crosses the aortic arch on the
left)—through the superior
mediastinum behind the root of
long—to esophagus and forms
the esophagus plexus —ant. and
post. trunks—enter abdominal
cavity through the esophageal
opening of diaphragm—divided into terminal branches.
• Main branches:
— superior laryngeal n.
* internal laryngeal n.(mucous
membrane of larynx above
the level of vocal folds)
* external laryngeal n.(supplies
the cricothyroid m.)
— cervical cardiac branches
— pharyngeal branch
• Main branches:
— recurrent laryngeal nerve(winds the subclavian a. or the aortic
arch—ascends in groove between the trachea and esophagus—
enters larynx): mucous membrane of the larynx below the level
of vocal folds and rest m. of larynx.
• Main branches:
— bronchial branches
— esophageal branches
— anterior and posterior
gastric branches(stomach)
— hepatic branches
— celiac branches
• Main branches:
— bronchial branches
— esophageal branches
— anterior and posterior
gastric branches(stomach)
— hepatic branches
— celiac branches
XI. Accessory nerve
• Contains somatic motor fibers arising
from the accessory nucleus(spinal root)
and lower part of nucleus ambiguus
(cranial root).
• Emerges from the posterolateral sulcus
of medulla oblongata—through the
jugular foramen—descends between
the internal carotid artery and internal
jugular vein—passes back and
downwards to strnocleidomustoid
muscle
XII. Hypoglossal nerve:
• Emerges from the anterolateral sulcus (between the olive and
pyramid) of medulla oblongat
—through the hypoglossal canal
—descends between theinternal
carotid artery and internal
jugular vein—passes forwards
over the internal and external
arteries at the level of the angle
of mandible— enters the tongue.
• Supplies the intrinsic and
extrinsic muscles of tongue