FACIAL NERVE PPT

1. FACIAL NERVE
GUIDED BY:-
DR P VIJAY SUNIL REDDY (PROFESSOR & HOD)
DR SHAILENDRA SINGH CHATURVEDI (READER)
DR PRAMOD V (READER)
DR HIROJ BAGDE (READER)
DR ABHILASHA SINGH (SENIOR LECTURER)
PRESENTED BY:-
DR SANGHAMITRA
GHOSH
(PG STUDENT)

2. CONTENTS:- Introduction
 Key facts
 Facial Nerve Embryonic Development
 Surface Marking
 Facial nerve functional component
 Origin
 Nuclei
 Course
 Branches and distribution
 Branches and communication
 Ganglia associated with the facial nerve
 Function

3.  Facial nerve blood supply
 Applied anatomy
 Clinical manifestation associated with facial nerve damage
 Conclusion
 References

4.  Seventh cranial nerve
 Known as queen of face
 Nerve of the second branchial
arch
Introduction

7. Type – Mixed nerve
(motor and sensory)
Origin – Pons of brain stem
Intracranial branches- Greater petrosal nerve,
Communicating branch
with otic ganglion,
Nerve to stapedius,
Chorda tympani
KEY FACTS

8. Extracranial branches- Post auricular nerve,
Branch to posterior
diagastric belly
Branch to stylomastoid
muscles
Temporal branch,
Zygomatic branch,
Buccal branch,
Marginal mandibilar branch
Cervical branch.

9. Field of innervation-
Motor : Facial expression muscles,
posterior belly of digastric muscle,
stylohyoid muscle,
stapedius muscle.
Special sensory : Taste from anterior 2/3 of the
tongue
Parasympathetic: Submandibular gland ,
Sublingual gland,
lacrimal glands
Clinical relations – Palsy
Inferior medial pontine syndrome

10. Embryology
Pons develops from metencephalon
Facial nerve embryonic development

11.  During first 3 months of prenatal life course,
branching pattern and anatomical relationships
are established
 Untill about 4 years of age nerve is not fully
developed.
At 3rd week of gestation first identifiable nerve
tissue is seen (FACIO-ACOUSTIC ) primordium or
crest.
FACIO-ACOUSTIC primordium gives rise to CN 7th
and 8th

12. During fourth week:-
The facial portion extents to placode
The acoustic portion terminates
to otocyst.
By the end of the 4th week
the facial and acoustic portion
are more distinct.

13. During fifth week:-
At early 5th week the geniculate ganglion forms the
distal part of primordium.
It separates into 2 branches main
trunk of facial nerve and
chorda tympani.

14. During 6th week :-
At the end of 5th week the facial
motor nucleus is recognizable.
The motor nuclei VI and VII
cranial nerve initially lie in close
proximaty.
The internal genu forms as
metencephalon, it elongates
and CN VI nucleus ascends

15. During 7th week:-
The geniculate ganglion is well defined and facial nerve root
are recognizable
Nervus intermedius arises from the geniculate ganglion and
passes to brain stem
Motor root fibres pass mainly caudal to ganglion
Proximal branches form in the 6th week, posterior auricular
branch, branch of digastric

17. During 8thweek:-
Early:-
Temporofacial and
cervicofacial divisions
present .
late :-
5 major peripheral
Subdivisions present.

18. Surface marking
Short horizontal line joining :-
 Middle of the anterior border of the
mastoid process.
Behind the neck of the mandible

20. Functional component Nuclei Distribution Function
GVE
( general visceral
efferent )
Superior salivatory
nucleus (lies in the
pons lateral to main
motor nucleus of VII)
Submandibular and
sublingual salivary
glands.
Preganglionic
secretomotor
SVE
( special visceral
efferent )
Motor nucleus of
facial nerve(lies in
lower part of pons)
Muscles of facial
expression,stylohyoid
,posterior belly of
digastrics,platysma
and stapedius.
Facial expression
SVA
( special viseral
afferent)
Nucleus of tractus
solitaries (lies in
medulla)
Taste buds in the ant
2/3rd of the tongue
except vallate
papillae
Taste sensations
GSA
(general somatic
afferent
Spinal nucleus of Vth
nerve
Part of skin of
external ear
Extroceptive
sensation.
(pain, temp, touch)
Facial nerve
functional components :-

23. Origin
It originates from cerebellopontine angle
– lateral part of pontomedullary junction.

24. The facial nerve originates from the following nuclei:-
1) Motor nucleus of the facial nerve :-
The nerve belongs to the SVE coloum, It lies in the lower
part of the pons

25. 2) Superior salivatory and lacrimal nuclei (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.

26. (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

27. (4) GSA fibers:-
Through these fibers to acoustic meatus &
back of auricle through communication from
auricular branch of vagus. These fibers
terminate in main sensory nucleus & spinal
nucleus of 5 th nerve

28. Course
Intracranial course and branches-
Cerebellopontine angle,
Internal acoustic meatus (Nervus intermedius joins)
Geniculate ganglion (sensory fibres) is deep in internal acoustic meatus
Greater petrosal nerve
Travels along medial wall of tympanic (middle ear) cavity
a) Branch to stapedius (attached to stapes)
b) Chorda tympani (This passes anteriorly across tympanic
membrane into Infratemporal fossa where it joins lingual nerve)
Emerges at stylomastoid foramen.

30. Extracranial course and branches:-
Outside stylomastoid foramen ,
1) Occipital belly of occipitofrontalis, stylohyoid and
posterior belly of diagastrics.
2) Cutaneous sensation from skin of external auditory
meatus.
3) Nerve enters parotid gland where it forms intricate plexus.

32. Occipital belly
of
occipitofrontalis

34. Branches of distribution
• Intracranial :-
a. Greater petrosal nerve.
b. Nerve to stapedius
c. Chorda tympani
• Extracranial :-
a. Posterior auricular nerve
b. Digastrics nerve
c. Stylohyoid nerve
• Terminal branches:-
a. Temporal branch
b. Zygomatic branch
c. Buccal branch
d. Marginal mandibular branch
e. Cervical branch

37. Geniculate ganglion:-
Ganglia associated with the facial nerve
 Located on the 1st bend of facial nerve, in relation
to the medial wall of the middle ear.
 It is a sensory ganglion.
 The taste fibers present in the nerve are peripheral
processes of pseudounipolar neurons present in
the geniculate ganglion.

38. Submandibular ganglion:-
 Parasympathetic ganglion.
 For relay of secretomotor fibres to the submandibular and
sublingual glands.

39. Pterygopalatine ganglion:-
 Parasympathetic ganglion.
 Secretomotor fibers meant for the lacrimal gland
relay in this ganglion.

40. Pterygopalatine
ganglion:-

41. Facial nerve blood supply (vasa nervorum)
The facial nerve gets its blood from:-
1 Anterior inferior cerebellar artery- At the cerebellopontin
angle
2 Labyrinthine artery- Within the internal acoustic meatus.
3 Superficial petrosal-geniculate ganglion and nearby parts.
4.Stylomastoid artery- mastoid segment
5. Posterior auricular artery- Distal to stylomastoid foramen.

42. 1 Taste sensation from ant 2/3rd of the tongue and
soft palate
2 ( pain ,touch and temperature ) from the auricle
,posterior part of external acoustic meatus and
tympanic membrane.
3 Helps in facial expression
4 Controls the secretion of tears ,saliva and mucus in
nasal and oral cavities)
FUNCTIONS

43. Testing of Facial Nerve Branches
Testing the Temporal branches of the facial nerve:-
To test the function of the temporal branches
of the facial nerve, a patient is asked to frown and wrinkle
his or her forehead.
Testing the Zygomatic branches of the facial nerve:-
The patient is asked to close their eyes tightly.

44. Testing the buccal branches of the facial nerve :-
 Puff up cheeks (buccinator)
 Smile and show teeth (orbicularis oris)
 Tap with finger over each cheek to detect ease of air
expulsion on the affected side

45. The marginal mandibular nerve may be injured during
surgery in the neck region, especially during excision of the
submandibular salivary gland or during neck dissections.

46. Applied anatomy
Facial nerve paralysis:-
Involves paralysis of any structure innervated by the facial
nerve.
The facial nerve is long and relatively convoluted, so a
number of causes may result in facial nerve paralysis .
The most common is bell’s palsy

47. Motor neuron diseases:-
The motor neuron diseases are a hetrogenous group of
progressive neurological disorders characterized by
degeneration of lower motor neurons, the cells that controls
essential voluntary muscle activity such as speaking, walking,
breathing and swallowing.
The neurons have cell bodies in the cranial nerve nuclei or in
the ant horn of the spinal cord and synapse directly on muscle
and /or upper motor neurons(which have cell bodies in the
brain as synapse on lower motor neuron)

48. Upper motor neuron:-
Upper motor neuron lesions occur in
conditions affecting motor neurons in the
brain or the spinal cord such as stroke,
multiple sclerosis,traumatic brain injury and
cerebral plasy.

49. Lower motor neuron:-
A lower motor neuron lesion affects nerve
fibres travelling from the anterior horn of the
spinal cord or the cranial motor nuclei to the
relevant muscles.

52. Bell’s Palsy:-
Most common cause of facial nerve paralysis.
There is no known cause of Bell’s Palsy, although it has been associated
with herpes simplex infection.
Bell’s palsy may develop over several days and may last several months.
It is typically diagnosed clinically, in patients with no risk factors for other
causes, without vesicles in the ear and with no other neurological signs.
Recovery may be delayed in the elderly or in those with a complete
paralysis.
Bell’s palsy is often treated with corticosteroids.

53. Bell's phenomenon:-
Is the upward diversion of the eye ball on attempted
closure of the lid is seen when eye closure is incomplete.

54. Features of Bell’s Palsy:-
 Unilateral involvement
 Inability to smile, close eye or raise eyebrow
 Whistling impossible
 Drooping of corner of the mouth
 Inability to close eyelid (Bell’s sign)
 Inability to wrinkle forehead
 Loss of blinking reflex
 Slurred speech
 Mask like appearance of face
 Loss/ alteration of taste

56. Infection:-
1) Ramsy-Hunt syndrome:-
• Reactivation of herpes zoster virus, as well as being
associated with bell’s palsy,
• Dorsal root ganglion of the facial nerve is associated with
vesicles affecting the ear canal and is termed Ramsy Hunt
syndrome.

58. 2)Otitis media :-
• Is an infection in the middle ear which can spread to the
facial nerve and inflame it.
• Compress the nerve in its canal.
• It usually presents in an ear with chronic discharge
(otorrhoea) or hearing loss with or without ear
pain(otalgia)

60. Inflammation
The middle ear inflamation can spread to canalis
facialis of the temporal bone.
The facial nerve travels through this canal together
with the statoacousticus nerve.
In the case of inflammation, the nerve is exposed to
oedema and subsequent high pressure, resulting in a
peripheral – type palsy.

61. Facial nerve paralysis most commonly during
inferior alveolar nerve block:-
• It causes due to injection of local anesthesia into the capsule
of parotid gland.
• It can be prevented by using proper technique and by
avoiding insertion of needle into the parotid gland.
• Transient treatment ,self correcting within 3 hrs or less.

62. Clinical condition /syndrome Symptoms Site of lesion /possible cause(s)
Crocodile tears syndrome
Also called
 Bogorad syndrome
 Gustatolacrimal reflex
 Paraoxymal lacrimation
Spontaneous tearing in parallel
with the normal salivation of
eating
Facial paralysis (due to injury to facial
nerve proximal to the geniculate
ganglion ), when nerve fibres destined
for a salivary gland are damaged and
by accident regrow to tear gland.
Bilateral facial palsy Flat,expressionless,drooling
face
Bulbar lesion
Marcus gunn phenomenon Nursing infants will have rhythmic
upward jerking of their upper eyelid
(first described by marcus gunn in
1883)
An autosomal dominance condition
with incomplete penetrance
Congenital ptosis
Millard –gubler syndrome
 Also known as ventral
pontine syndrome.
Paralysis of the nerve- leads to
diplopia, loss of power to rotate the
affected eye outwards
Disruption of the Facial nerve (VII
cranial nerve )leads to the symptoms
including flaccid paralysis of the
muscles of facial expression and loss of
the corneal reflex
Damage of the VII nerve in pons a
unilateral lesion of the ventrocaudal
pons may involve the fibres of VI and
VI cranial nerve.
Clinical manifestation associated with facial nerve damage:-

63. The symptoms according to the level of injury of facial nerve:-
At internal auditory meatus; loss of lacrimation, stapedial reflex, taste
from most of anterior two-third of tongue, lack of salivation and paralysis
of muscles of facial expression.
Below geniculate ganglion; loss of stapedial reflex, taste from anterior
two- third of tongue, lack of salivation and paralayis of facial expression
muscles.
Region b/w nerve to stapedius and chorda tympani : loss of taste from
anterior two-third of tongue, lack of salivation and paralysis of facial
expression muscles.
Region below stylomastoid foramen : paralysis of facial expression
muscles.

65. 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.
Hence a complete understanding of its anatomy is
essential and care should be taken during surgical
procedures.
Conclusion

66. Refrences
1. Chaurasia’s BD Human Anatomy- Vol 3. 5th edition. CBS Publishers and Distributors Pvt. Ltd. 337-370
2. Monkhouse Stanley cranial nerves 1st edition Cambridge University Press,2006 functional anatomy.
3. DM Kadasne Kadasne’s textbook of anatomy volume 31st edition 1st Jaypee brothers medical
publishers (p) ltd. New Delhi. . 996-1001
4. Sembulingam k, Sembulingam p. Essentials of medical physiology, 3rd edition. Jaypee brothers medical
publishers (p) ltd. New Delhi. P619-627
5. Singh DR essentials of anatomy for dentistry students.1st edition. Wolters Kluwer India Pvt. Ltd. New
Delhi. 291-297.
6. G.J.Romanes Cunningham’s manual of practical anatomy 15th edition volume 3 head, neck and brain
oxford medical publications
7. Pal GP Illustrated textbook of Neuroanatomy
8. Sinnatamby chummy s. Last’s anatomy regional and applied 10th edition.