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By
Dr. Fekry ShataAssistant prof. of anatomy & embryology
Faculty of Dentistry Majmaa university
FACIAL NERVE7TH CRANIAL NERVE
Mixed*Has two roots:-1)-Motor :- facial nerve proper (large medial)
2)-Mixed:- nervus intermedius (small lateral) a. Parasympathetic. b. Sensory.
Small lateral sensory root(nervus intermedius)
Large medial motor root
MSSN
N.S. S.
T.N.
Has 4 nuclei
1- Motor nucleus in pons
4-Spinal trigeminal nucleus
2- Superior salivary nucleus in pons
3-Nucleus soliterius in M.O.
Facial nerve proper: purely motor .
*all muscles of face, scalp except levator palpapri superiosis
*All muscles derived from 2nd pharyngeal arch
Nervus intermedius:-parasympathetic:
-through submandibular ganglion: to sublingual & submandibular salivary gland-through Sphenopalatine ganglion: to lacrimal gland
Nervus intermedius:-Special sensation:
Taste sensation from anterior 2/3 of tongue
Nervus intermedius:-General sensation:
external auditory meatus
Small lateral sensory root(nervus intermedius)
Large medial motor root
Stylomastoidforamen
Stylomastoidforamen
1-Geniculate ganglion: gives rise to:- greater superficial
petrosal
n.
2- pterygopalatine g.
3- Submandibular g.
Geniculate ganglion
Greater superficial petrosal nerve
Vestibulocochlear nerve
G.S.P.N.
D.P.N.
Geniculate
ganglion
facial n.(7th n.)
Nerve to pterygoid canal(vidian nerve)
Mandibular nerve
lingual nerve.
facial n.(7th n.)
Chordatympani
1.Intracranial course2.Intracanalicular course3.Extracranial course
1.Intracranial course(inside cranial cavity)
Enter internal auditory meatus
Motor n. of facial
PONS
Motor n. of ABDUCENT
Internal genu
Facialcolliculus
PONS
Internal auditorymeatus
8th cranial n.
2.Intracanalicular course(inside facial canal)
(in middle ear)
PONS
Internal auditorymeatus
8th cranial n.
Geniculate ganglion
Greater superficial petrosal nerve
Facial canal
3.Extracranial course(in the face)
enter the face by passing through stylomastoid foramen
Geniculate ganglionFacial canal
Stylomastoidforamen
Stylomastoidforamen
Upper (temporofacial) division
Lower (cervicofacial) division
Retromandibularvein
E.C.A.
Medial pterygoid
Masseter
Parotid gland
Facial nerve
Upper (temporofacial)division
Lower (cervicofacial)division
PosteriorAuricular
nerve
Descending(n. to posterior
Belly ofDigastric)
nerve
Temporal branch
Zygomatic branch
Upper root of buccal
Lower root of buccal
Marginal (mandibular)branch
Cervical branch
1st part : no branches2nd part : (within middle ear or facial canal) 1- Greater superficial petrosal n. 2- Tympanic 3- Chorda tympani 4- Nerve to stapedius3- 3rd PART : Gives 7 branches A. before entering parotid gland: 1*post. Auricular n. 2*n.to post. belly of digastric B. Terminal (after entering parotid gland): 1*Temporal 2*Zygomatic 3*Buccal 4*Marginal(mandibular) 5*Cervical
Greater superficial petrosal nerve Origin: From geniculate ganglion.
Its fibers arise from: superior salivarv nucleus. contains secretomotor parasympathetic fibers.
Course: • Runs towards the foramen lacerum.
Termination: *At foramen lacerum joins deep petrosal nerve to form nerve of the
pterygoid canal (Vidian nerve). *In pterygopalatine fossa it joins the back of pterygopalatine ganglion.
Branches & distribution: • Taste fibers: to palate.• Preganglionic Parasympathetic fibers: to pterygopalatine ganglion.
G.S.P.N.
D.P.N.
Geniculate
ganglion
facial n.(7th n.)
Nerve to pterygoid canal(vidian nerve)
Tympanic branch
Small branches to tympanic plexus to with the 9th nerve.
Chorda tympani Origin: from facial nerve in temporal bone, a short distance
above stylomastoid foramen.
Course: -ascends in a bony canaliculus to the posterior wall of the
middle ear. -passes forwards across the upper part of tympanic
membrane. Termination:-joins lingual nerve (branch of mandibular nerve).
Distribution: 1.Taste fibers: anterior 2/3 of tongue.2. Preganglionic parasympathetic fibers to:- (1)-submandibular salivary glands. (2)-subligual salivary glands. (3)-glands in the anterior two thirds of tongue.
Choda tympani
Squamotympanicfissure
Lingual nerve
Mandibular nerve
lingual nerve.
facial n.(7th n.)
Chordatympani
Nerve to stapedius
motor fiber tothe stapediusmuscle of themiddle ear
Extracranial branches(in the face)
PosteriorAuricular
nerve
occipitalis
Auricularis
Descending(n. to posterior
Belly ofDigastric)
nerve
Temporal branchfrontalis
SAP Zygomatic
branch
Upper root of buccal
Lower root of buccal
Marginal (mandibular)branch
Cervical branch
Orbecularisoculi
platysma
1.LMNL*lesion in the facial
nerve or in the facial n.
*causes flaccid paralysis of all muscles of facial expression on the same side of the face.
(Bell's palsy).
Signs of the Lesion(same side of the face)
A Paralysis of the frontalis muscle: inability to raise the eyebrow.B. Paralysis of the orbicularis oculi muscle:
a. Inability to close the eye b. Loss of the corneal reflex.C. Paralysis of the orbicularis oris: inability to
whistle.D. Paralysis of the levators of the angle of the mouth:
drooping of the angle of the mouth.E. Paralysis of the buccinator muscle:
accumulation of food in vestibule of the mouth.F. Paralysis of the stapedius muscle:
hyperacusis (hypersensitivity to sounds).G. Affection of the chorda tympani:
a. loss of taste sensation from the anterior 2/3 of the tongue . b. decreased salivation.
H. Affection of the greater superficial petrosal nerve:
loss of lacrimation
2 .UMNL
• Due to: lesion in the corticobulbar fibers (above the level of nuclei).
• Leads to: =paralysis of the lower half of the contralateral
facial nucleus. =paralysis of the muscles of the lower half of the
opposite side of the face 1.inability to whistle, 2.drooping of the angle of the mouth. 3.accumulation of food in the vestibule of the
mouth.
Summary of para-sympathetic supply of
H&N
E.W.N.
MIDBRAIN
I.S.N.
M.O.
C.G.
S.P.G.
S.C.S.G.
Mandibularnerve S.M.G.
TympanicPlexus
InMiddle
earMandibular
nerve O.G.
S.S.N.
PONS
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