2. Table of contents
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• Introduction
• Surface marking
• Functional components
• Nuclei
• Course and relations
• Branches and distribution
• Ganglia
• Clinical anatomy
3. Introduction
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• Seventh cranial nerve
• Nerve of the second branchial arch
• The facial nerve consists of the facial nerve
proper and the intermedius nerve.
• Both the facial nerve proper and the
intermedius nerve emerge from the CNS in the
cerebellopontine angle at the caudal border of
the pons, between the abducens nerve and the
vestibulocochlear nerve .
4. Surface markings
4
• Marked by a short
horizontal line which
joins following two
points:
1) A point at the middle of
the anterior border of
the mastoid process.
2) Behind the neck of the
mandible.
5. Functional components
5
1. Special visceral orbranchial efferent:
muscles responsible for facial expression,
auricular muscles , posterior belly of digastric
muscle , stylohyoid and stapedius
2. General visceral efferent orparasympathetic:
Supplies secretomotor fibrers to
submandibular and sublingual salivary glands,
the lacrimal gland, and glands in nasal
mucosa and palate.
6. 6
3. Special visceral afferent fibres carry taste
sensations from the anterior two thirds of the
tongue via chorda tympani and soft and hard
palate via greater superficial prtrosal nerve.
4. General somatic afferent fibres bring general
sensation from the concha , posterosuperior
part of external canal and the tympanic
membrane.
8. Nucleus of facial nerve
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The fibres of the nerve arise from fournuclei
situated in the lower pons.
1. Motornucleus orbrachiomotor: lies deep in
the reticular formation of the lower pons.
2. Superiorsalivatory nucleus – parasympathetic.
3. Lacrimatory nucleus – parasympathetic.
4. Nucleus of tractus solitarius – gustatory and
also receives afferent fibres from the glands.
9. Supranuclearanatomy
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Voluntary responses of the facial
muscles arises from efferent
discharge from motor face area
of the cerebral cortex.
The motor face area is situated
on the pre central and post central
gyrus.
10. Discharges from the facial
motor area are carried through
fascicles of the corticobulbar tract
to the internal capsule, then
through the upper midbrain to the
lower brainstem, where they
synapse in the facial nerve
nucleus located in pons.
Corticobulbar tracts
arising from the cortical
representation of the upper face
area cross and recross in
reaching the pontine facial motor
nucleus
The tracts to lower face are
crossed only once.
Posterior view of the
brainstem
11. Intracranial course and relations
• Facial nerve is attached to the brainstem by two
roots : motor and sensory ( nervus intermedius)
which are attached to the lateral part of the lower
border of pons just medial to 8th
cranial nerve.
• The motor and sensory root runs laterally and
forwards, with the 8th
nerve to reach the internal
acoustic meatus. In the meatus the motor root
lies in a groove on the 8th
nerve with the sensory
root intervening.
• At the bottom of the meatus , the two roots fuse
to form a single trunk which lies in the petrous
temporal bone.
11
12. 12
Within the canal, the
course of the nerve can be
divided into three parts by
two bends:
1. First part is directed
laterally above the
vestibule.
2. Second part runs
backwards in relation to
the medial wall of the
middle ear, above the
promontory.
3. Third part is directed
vertically downwards
13. 13
• The first bend at the
junction of first and
second part is sharp and it
is called as genu.
• The second bend is
gradual and lies between
the promontory and the
aditus to the mastoid
antrum.
• Facial nerve leaves the
skull by passing through
the stylomastoid foramen.
14. 14
Intra cranial part 15-17mm
Intra temporal part
Meatal segment 8-10mm
Labyrinthine segment4mm
Tympanic segment 11mm
Mastoid segment 13mm
15. Extracranial course
• The facial nerve crosses the
lateral side of the base of the
styloid process.
• It enters the posteromedial
surface of the parotid gland,
runs forwards through the
gland crossing the
retromandibular vein and the
external carotid artery.
• Behind the neck of the
mandible it divides into its five
terminal branches which
emerge along the anterior
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16. Branches of facial nerve
Greatersuperficial prtrosal nerve:
Arises from geniculate ganglion
Carries secretomotor fibres to lacrimal gland and glands
of nasal mucosa and palate
Nerve to stepedius:
Arises at the level of second genu
Supplies stepedius muscle
Chorda tympani:
Arises from the middle of vertical segment Leaves the
middle ear by passing though petrotympanic fissure
Carries secretomotor fibres & gustatory fibres
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17. 17
Communicating branch:
It joins auricular branch of vagus
Supplies concha , retroauricular groove , posterior
meatus & outer surface of tympanic membrane
Posteriorauricularnerve:
It supplies pinna , occipital belly of frontalis &
communicates with auricular branch of vagus
Mascularbranches:
To stylohyoid & posterior belly of digastric
18. 18
Peripheral branches:
Arise after crossing styloid
process
It divides as upper temporofacial
& lower cervicofacial
Further divide in to smaller
branches
Temporal , Zygomatic, Buccal,
Mandibular & Cervical
Together forms pes anserinus
Supplies all muscles of facial
expression
20. Ganglia
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1. The geniculate ganglion is located on the first
bend of the facial nerve in relation to the medial
wall of the middle ear. It is a sensory ganglion.
The taste fibres present in the nerve are
peripheral processes of pseudounipolar neurons
present in the geniculate ganglion.
2. The submandibularganglion is a
parasympathetic ganglion for relay of
secretomotor fibre to the submandibular and
sublingual glands.
3. The pterygopalatine ganglion is also a
parasympathetic ganglion. Secretomotor fibres
present for the lacrimal gland relay in this
ganglion.
21. Vascularsupply
Ce re be llo po ntine ang le :Anterior-inferior
cerebellar artery
Inte rnalaudito ry canal:Labyrinthine artery
Ge niculate g ang lio n and adjace nt facial
ne rve : suprficial petrosal artery
Masto id se g m e nt :Stylomastoid artery
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22. Surgical landmarks of facial
nerve
1. Processus
cochleariformis
2. Oval window & Horizontal
canal
3. Short process of incus
4. Pyramid
5. Tympanomastoid suture
6. Digastric ridge
1. Cartilaginous pointer
2. Tympanomastoid
suture
3. Styloid process
4. Posterior belly of
digastric
Formiddle ear&
mastoid surgery
Forparotid surgery
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23. Variation and anomalies of
facial nerve
1. Bony dehiscence
2. Prolapse of nerve
3. Hump
4. Bifurcation &
trifurcation
5. Bifurcation &
enclosing the
stapes
6. Between oval and
round windows
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