facial nerve is the seventh cranial nerve supplies the submandibular, sublingual, lacrimal glands, the mucosal glands of the nose, palate, pharynx and taste fibres, and on being injured it leads to loss of lacrimation, loss of salivation, loss of taste sensation and paralysis of the muscles of facial expression.

1. P R E S E N T E D B Y : R A K A S H R E E C H A K R A B O R T Y
SEMINAR ON
FACIAL NERVE

2. PURPOSE STATEMENT
At the end of the presentation, the learner should be able to
describe the development, surface marking, functional
component, course and relation, branches,
distribution, conditions involving facial nerve
weakness, symptoms according to facial nerve injury
and diagnosis of facial nerve disorder.

3. S/n
o
Learning objectives Domain Level Criteria Condition
1 Explain the development of facial nerve Cognitive Must
know
All -
2 Explain surface marking, functional components,
nuclei of facial nerve
Cognitive Must
know
All -
3 Explain the course and relation, branches,
distribution and ganglions associated with facial
nerve.
Cognitive Must
know
All -
4 Explain the blood supply of facial nerve Cognitive Must
know
All -
5 Explain the conditions involving facial nerve
weakness, symptoms according to facial nerve
injury and diagnosis of facial nerve disorder
Cognitive and
psychomotor
Must
know
All -

4. CONTENTS
 INTRODUCTION
 DEVELOPMENT
 SURFACE MARKING
 FUNCTIONAL COMPONENT
 NUCLEI
 COURSE AND RELATION
 BRANCHES
 DISTRIBUTION
 GANGLION
 BLOOD SUPPY
 CONDITIONS INVOLVING FACIAL NERVE WEAKNESS
 SYMPTOMS ACCORDING TO FACIAL NERVE INJURY
 DIAGNOSIS OF FACIAL NERVE DISORDER
 CONCLUSION
 REFERENCES

5. INTRODUCTION
 The Facial nerve is the seventh of twelve paired cranial
nerves, it is a mixed nerve with motor and sensory roots.
 It emerges from the brain stem between the pons and the
medulla, controls the muscles of facial expression
 It functions in the conveyance of taste sensations from
the anterior two thirds of the tongue and oral cavity
 It also supplies preganglionic parasympathetic fibres
to several head and neck ganglia

6. DEVELOPMENT
 The facial nerve is developmentally derived from the
hyoid arch, which is the second branchial arch
 The motor division of facial nerve is derived from
the basal plate of the embryonic pons
 The sensory division originates from the cranial
neural crest

7. Facial nerve course, branching pattern, and
anatomical relationships are established during the
first 3 months of prenatal life.
The nerve is not fully developed until about 4 years
of age.
The first identifiable Facial Nerve tissue is
seen at the third week of gestation-
facioacoustic primordium or crest

8. Facial nerve embryology: 4th week
 By the end of the 4th week,
the facial and acoustic
portions are more distinct
 The facial portion extends
to placode.
 The acoustic portion
terminates on otocyst

9. Facial nerve embryology: 5th week
 Early 5th week, the
geniculate ganglion
forms from distal part of
primordium.
 It separates into 2
branches: main trunk
of facial nerve and
chorda tympani

10. Facial nerve embryology: 6th week
 Near the end of the 5th
week, the facial motor
nucleus is recognizable
 The motor nuclei of VI
and VII cranial nerves
initially lie in close
proximity.
 The internal genu
forms as
metencephalon, it
elongates and CN VI
nucleus ascends

11. Facial nerve embryology: 7th week
Early 7th week, geniculate ganglion is well-
defined and facial nerve roots are
recognizable.
The nervus intermedius arises from the ganglion
and passes to brainstem. Motor root fibers pass
mainly caudal to ganglion

12. Proximal branches form in the 6th week,
posterior auricular branch, branch of digastric.
Early 8th week, temporofacial and cervicofacial
divisions present.
Late 8th week, 5 major peripheral subdivisions
present

13. FACIAL NERVE ORIGIN

15. SURFACE MARKING
It is marked by a short horizontal line which joins the
following two points:-
 A point at the middle of the anterior border of the mastoid
process. The stylomastoid foramen lies 2cm deep to this
point
 Behind the neck of the mandible. Here the nerve divides
into 5 branches for the facial muscles.

16. FUNCTIONAL COMPONENTS
5 FUNCTIONAL COMPONENTS – Facial N. is the
nerve of the 2nd pharyngeal arch.
 SPECIAL VISCERAL OR BRANCHIAL EFFERENT: -
muscles responsible for facial expression.
 -elevation of hyoid bone
 SPECIAL VISCERAL AFFERENT FIBRES: -carry taste
sensations from the anterior two third of the tongue
except from the vallate papillae and from palate

17.  GENERAL VISCERAL EFFERENT OR
PARASYMPATHETIC: - these fibres are secretomotor to
the submandibular and sublingual salivary glands,
lacrimal glands and glands to the nose , palate and
pharynx.
 GENERAL VISCERAL AFFERENT COMPONENT: -
caries afferent impulses from the submandibular and
sublingual salivary glands, lacrimal glands and glands to
the nose , palate and pharynx.
 GENERAL SOMATIC AFFERENT FIBRES:- innervate a
part of the skin of the ear.

19. NUCLEI
 The fibres of the nerve arises from the four nuclei
situated in the lower pons
 1. Motor nucleus of facial nerve (SVE):
It lies in the lower part of the pons
 2. Superior salivatory nucleus (GVE):
It lies in the pons lateral to the main motor nucleus
of VII and gives rise to secretomotor
parasympathetic fibers that pass in greater
superficial petrosal nerve and chorda tympani

20.  3. Nucleus of tractus solitarus (SVA):
It lies in the medulla, receives the taste sensation from
the anterior 2/3 of the tongue via the central processes of
the cells of the geniculate ganglion of the facial nerve.
 4. Lacrimal nucleus
It lies in the pons lateral to the main motor nucleus of
VII and gives rise to secretomotor
parasympathetic fibers.

21. COURSE AND RELATION
INTRACRANIAL COURSE:
 The facial nerve is attached to the brainstem by 2 roots,
motor and sensory. The sensory root is also known as
Nervus intermedius.
 The 2 roots of the facial nerve are attached to the lateral
part of the lower border of the pons just medial to the 8th
cranial nerve.
 The 2 roots run laterally and forwards with the 8th nerve to
reach the internal acoustic meatus.

22.  In the meatus the motor root lies in a groove on the 8th
cranial nerve, with the sensory root intervening.
 Here the 7th and 8th nerves are accompanied by the
labyrinthine vessels. At the bottom or the fundus of the
meatus, the two roots, sensory and motor fuse to form a
single trunk, which lies in the petrous temporal bone.

23. Within the canal, the course of the canal can be divided into 3 parts
by 2 bends:-
The 1st part is directed laterally above the vestibule
The 2nd part runs backwards in relation to the medial wall of the
middle ear,above the promontory.
The 3rd part is directed vertically downward behind the promontory.
The 1st bend at the junction of the first and second parts are sharp. It
lies over the anterosuperior part of the promontory and is also known
as genu.
The 2nd bend is gradual and lies between the the promontory and the
aditus to the mastoid antrum.
The facial nerve leaves the skull by passing through the stylomastoid
foramen.

25.  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 five terminal branches
which emerge along the anterior border of the
parotid gland.

27. Branches of Distribution
In face
A. Temporal
B. Zygomatic
C. Buccal
D. Marginal
mandibular
E. Cervical
Stylomastoid
foramen
A. Posterior auricular
B. Nerve to
stylohyoid
C. Nerve to digastric
(posterior belly)
Facial canal
A. Nerve to stapedius
B. Chorda tympani
C. Greater petrosal
nerve

28. TERMINAL BRANCES OF THE FACIAL NERVE AND THE
MUSCLES THEY INNERVATE
a. Temporal
a) Frontalis
b) Orbicularis Oculi
c) Corrugator supercilli
b. Zygomatic
a. Orbicularis oculi
c. Buccal
a. Procerus
b. Zygomaticus
c. Levator labii superioris
d. Buccinator
e. Orbicularis oris
d. Marginal mandibular
a. Depressor anguli oris
b. Depressor labii inferioris
c. Mentalis
e. Cervical

30. DISTRIBUTION

31. The greater petrosal nerve:
• Carries gustatory and parasympathetic fibres
• Arises from the geniculate ganglion of the facial
nerve and enters the middle cranial fossa
through the hiatus for the greater petrosal
nerve on the anterior surface of the petrous
temporal bone.
• It proceeds towards the foramen lacerum where
it joins the deep petrosal nerve which carries
the sympathetic fibres to form the nerve of the
pterygoid canal.
Nerve to stapedius:
• Arises opposite the pyramid of the middle ear
• Supplies the stapidius muscle

32. The chorda tympani:-
 Arises in the vertical part of the facial canal about
6mm above the stylomastoid foramen
 Runs upwards and forwards in the bony canal.
Enters the middle ear and runs forwards in close
relation to the tympanic membrane.
 It leaves the middle ear by passing through the
petrotympanic fissure.It passes medial to the spine
of the sphenoid and enters the infratemporal fossa.
Here it joins the lingual nerve through which it is
distributed.

33. The posterior auricular nerve:-
 Arises just below the stylomastoid foramen
 Ascends between the mastoid process and the external
acoustic meatus
 Supplies –
 The auricularis posterior
 The occipitalis
 The intrinsic muscles on the back of the auricle
The digastric branch:
 Arises close to the posterior auricular nerve .
 It is short and supplies the posterior belly of the
digastic.

34.  The temporal branch:-
 It crosses the zygomatic arch
 It supplies the:
 The auricularis anterior
 The auricularis superior
 The intrinsic muscles on the lateral surface of the ear
 The frontalis
 The orbicularis oculi
 The corrugator supercilli
 The zygomatic branch:-
 Crosses the zygomatic bone and supply the orbicularis oculi.
 The buccal branch:-
 The upper buccal branch runs above the parotid duct
 The lower buccal branch runs below the duct
 The Buccal Branches of the facial nerve (infraorbital branches),
of larger size than the rest of the branches, pass horizontally
forward to be distributed below the orbit and around the
mouth

35.  The marginal mandibular branch of the facial
nerve passes forward beneath the platysma and
depressor anguli oris.
 It supplies the muscles of the lower lip and chin,
and communicating with the mental branch of
the inferior alveolar nerve.
 The cervical branch of the facial nerve runs forward
 It forms a series of arches across the side of the neck
over the suprahyoid region.
 One branch descends to join the cervical cutaneous
nerve from the cervical plexus; others supply the
Platysma. Also supplies the depressor anguli oris.

37. GANGLIONS
THE GANGLIA ASSOCIATED WITH THE FACIAL
NERVE ARE:-
1. THE GENICULATE GANGLIA :-
a. Sensory ganglion
b. Located on the first bend of the facial nerve in
relation to the medial wall of the middle ear.
c. The taste fibres present in the nerve are peripheral
processes in the geniculate ganglion.

38. 2.THE SUBMANDIBULAR GANGLION:-
a) Parasympathetic ganglion
b) Relay of secretomotor fibres to the
submandibular and sublingual glands
c) Topographically related to lingual nerve
d) Functionally connected to chorda tympani
branch of facial nerve

39. 3.THE PTERYGOPALATINE GANGLION:-
a) Largest Parasympathetic peripheral ganglion
b) Relay of secretomotor fibres to the lacrimal
gland,mucous glands of the nose,paranasal
airsinus,palate and pharynx.
c) Topographically related to maxillary nerve
d) Functionally related to facial nerve though its
greater petrosal branch

40. Facial Nerve blood supply
 The facial nerve gets it’s blood supply from 4 vessels:
 Anterior inferior cerebellar artery – at the cerebellopontine angle
 Labyrinthine artery (branch of anterior inferior cerebellar artery) –
within internal acoustic meatus
 Superficial petrosal artery (branch of middle meningeal artery) –
geniculate ganglion and nearby parts
 Stylomastoid artery
(branch of posterior auricular artery) – mastoid segment
 Posterior auricular artery supplies the facial nerve at & distal to
stylomastoid foramen
 Venous drainage parallels the arterial blood supply

41. CONDITIONS RESULTING IN FACIAL NERVE
WEAKNESS
1.Bell’s Palsy
2.Ramsay Hunt Syndrome
3. Melkersson – Rosenthal syndrome

42. BELL’S PALSY
 The most common condition resulting in facial nerve
weakness or paralysis is Bell’s palsy, named after Sir
Charles Bell who Ist described the condition. The
underlying cause of this condition is not known but it
may be due to a virus infection of the nerve. This
swelling results in presence on the nerve fibres and
their blood vessels, causing facial paralysis.
 0.2% population is affected
 Middle aged people are more affected and a higher
tendency in women.

44.  Bell’s Palsy begins with slight pain around one ear
followed by abrupt paralysis of the muscles of that side
of the face:
 Marked facial asymmetry
 Eyebrow droop
 Smoothing out of forehead and nasolabial folds
 Dropping of the corner of the mouth
 Uncontrolled tearing
 Unable to close eye
 Difficulty in keeping food in mouth while chewing on
affected side
 Lips can’t be tightly held together or pursed.
 The degree of paralysis should peak within several days
of onset- never longer than 2 weeks.
 Viral and bacterial infections and autoimmune disorders
are the common causes of Bell’s Palsy.
SIGNS AND SYMPTOMS OF BELL’S PALSY

45. RAMSAY HUNT SYNDROME
 Causative virus is varicella zoster virus (VZV) which
is the virus that causes chicken pox. The virus resides
on the nerve tissue in dormant state on the nerve
ganglia after the initial infectious stage.When the
virus is reactivated the resulting blisters are called
“Shingles”.

46. • Symptoms:
 Facial paralysis
 Ear pain
 Vesicles
 Sensorineural
hearing loss
 Vertigo

47. MELKERSSON – ROSENTHAL SYNDROME
 It is a rare neurological disorder characterized by
 Recurring facial paralysis,
 Swelling of the face and lips (usually the upper lip),
 The development of folds and furrows in the tongue.

48. MELKERSSON – ROSENTHAL SYNDROME
 Onset is in childhood or early adolescence.
 The lip may become hard, cracked, and fissured with
a reddish-brown discoloration.
 Eteology unknown.

49. OTHER FACIAL NERVE DISORDERS
 Facial spasm: surgery to correct this problem may
involve (a) Intentional weakening of nerve through
an incision on the face or (b) relieving pressure on
the nerve adjacent to the brain.
 Mastoid infection:
It is due to acute or chronic middle ear infections.
In acute infections the weakness usually subsides
as the infection is controlled and the swelling
around the nerve subsides.

50.  Post operative facial nerve weakness
Delayed weakness or paralysis following
reconstructive middle ear surgery is uncommon,
but occurs at times due to swelling of the nerve
during healing period.
 Hemifacial spasm – uncommon disease of
unknown cause which results in spasmodic
contractions of one side of the face.
 Brain disease- Tumors and circulatory
disturbances of the nervous system may cause
facial N paralysis eg. Stroke.

51. SYMPTOMS ACCORDING TO THE LEVEL OF
INJURY TO THE FACIAL NERVE

52. DIAGNOSIS OF FACIAL NERVE DISORDERS
An extensive evaluation is often necessary to determine the cause
of the disorder and localize the area of nerve involvement.
1. Stapedius nerve test – (Hearing test)
2. Petrosal nerve test – (Tear test)
3. Electrical tests
a.Nerve excitability tests
b.Electroneurography

53. CONCLUSION
 Concluding that facial nerve, the seventh cranial
nerve supplies the submandibular, sublingual,
lacrimal glands, the mucosal glands of the nose,
palate, pharynx and taste fibres, and on being
injured it leads to loss of lacrimation, loss of
salivation, loss of taste sensation and paralysis of the
muscles of facial expression.

54. • G R A Y ’ S A N A T O M Y . 2 N D E D I T I O N . E L S E V I E R
P U B L I C A T I O N 2 0 1 0
• A T L A S O F A N A T O M Y . 2 N D E D I T I O N . T H I E M E
M D I C A L P U B L I S H E R S , N E W Y O R K 2 0 0 9 .
• H U M A N A N A T O M Y – B . D . C H A U R A S I A . 2 N D
E D I T I O N C B S P U B L I C A T I O N S 2 0 1 0 .
• O R A L M E D I C I N E , D I A G N O S I S A N D
T R E A T M E N T – B U R K E T ’ S 1 1 T H E D I T I O N .
• T E X T B O O K O N O R A L P A T H O L O G Y – 6 T H
E D I T I O N . 2 0 1 0 . S H A F E R , H I N E , L E V Y .
• W I K I P E D I A . N E T
REFERENCES

55. THANK YOU