Contents
1.
2.
3.
4.
5.
6.
7.
8.

Introduction
Embryology
Nuclei of origin
Course & Relations
Branches of facial nerve
Fun...
10.Variations of nerve
11.Testing of facial nerve
12.Identification of facial nerve
13.Complications of facial dissection
...
Introduction
 The Facial nerve is the seventh of twelve paired cranial
nerves, it is a mixed nerve with motor and sensory...
Embryology
 The facial nerve is developmentally derived from the
hyoid arch, which is the second branchial arch
 The mot...
 Facial nerve course, branching pattern, and anatomical
relationships are established during the first 3 months
of prenat...
Facial nerve embryology: 4th week
 By the end of the 4th week,
the facial and acoustic
portions are more distinct
 The f...
Facial nerve embryology: 5th week
 Early 5th week, the
geniculate ganglion
forms from distal part
of primordium

 It sep...
Facial nerve embryology: 6th week
 Near the end of the 5th
week, the facial motor
nucleus is recognizable
 The motor nuc...
Facial nerve embryology: 7th week
 Early 7th week, geniculate ganglion is well-defined and
facial nerve roots are recogni...
 Proximal branches form in the 6th week, posterior
auricular branch, branch of digastric
 Early 8th week,
temporofacial ...
Nucleui of Origin
1. Motor nucleus of facial nerve (SVE):
It lies in the lower part of the pons
2. Superior salivatory nuc...
3. Nucleus solitarus (SVA):
It lies in the medulla, receives the taste sensation
from the anterior 2/3 of the tongue via t...
Facial nerve origin
COURSE OF FACIAL NERVE
Internal course: the motor fibres passes dorsally and
medially forming a loop around the abducent n...
The facial nerve is formed mainly of two parts:

1- Facial nerve proper (motor): arising from facial
motor nucleus in pons...
Course and relations:
I- Intracranial (intrapetrosal) course
II- Extracranial course
I- The intrapetrous course:
The nerve passes laterally with the vestibulocochlear
nerve (CN VIII) to the internal auditary...
II- Extracranial course:
 As it emerges from the stylomastoid foramen, it runs
forwards in the substance of the parotid g...
Branches
Intracranial
Greater petrosal nerve
Nerve to stapaedius
Chorda tympani

Intratemporal
Intrameatal
Labyrinthine
...
Extracranial
Posterior Auricular Nerve
Digastric nerve
Stylohyoid nerve

The five terminal branches
Temporal branch
Zygo...
 Within the facial canal:
1- Nerve to stapedius: supplies the stapedius muscle.


2- Greater superfacial petrosal nerve ...
3- Chorda tympani nerve:
 It arises from the facial nerve 6 mm above the
stylomastoid foramen and runs upwards to perfora...
 It comes out of the tympanic cavity through the
petrotympanic fissure to the infratemporal fossa
where it joins the ling...
II- At the exit from the stylomastoid foramen

1- Posterior auricular nerve:
to the auricularis posterior and the occipita...
TERMINAL BRANCHES
The temporal branches of the facial nerve (frontal
branch of the facial nerve) crosses the zygomatic
arc...
The more anterior branches supply the frontalis, the
orbicularis oculi, and corrugator supercilii, and
join the supraorbit...
The zygomatic branches of the facial nerve (malar
branches) run across the zygomatic bone to the
lateral angle of the orbi...
The Buccal Branches of the facial nerve
(infraorbital branches), of larger size than the rest
of the branches, pass horizo...
The buccal branch supplies these muscles
MUSCLE

ACTION

Risorius

Smile

Buccinator

Aids chewing by holding cheeks flat
...
 The marginal mandibular branch of the facial
nerve passes forward beneath the platysma and
depressor anguli oris.
 It s...
 The cervical branch of the facial nerve runs
forward
 It forms a series of arches across the side of the
neck over the ...
Branches

Branches of
communication

Branches of distribution
Branches of Communication
Internal acoustic meatus
Geniculate ganglion

Vestibulocochlear nerve
A. Greater petrosal nerve
...
Branches of Distribution

Facial canal
A. Nerve to stapedius
B. Chorda tympani

Stylomastoid
foramen
A. Posterior auricula...
Facial Nerve: Functional Components
 Special Visceral Efferent/Branchial Motor
 General Visceral Efferent/Parasympatheti...
Special Visceral Efferent/Branchial Motor
 Premotor cortex  motor cortex 
corticobulbar tract  bilateral facial motor
...
General Visceral Efferent/Parasympathetic
Superior salivatory nucleus (pons)

nervus intermedius
greater/superficial petro...
Superior salivatory nucleus
nervus intermedius

chorda tympani
joins lingual nerve
submandibular ganglion
postganglionic p...
General Sensory Afferent/Sensory
Sensation to auricular concha, EAC wall, part
of TMJ, postauricular skin
Through Cell bod...
Special Visceral Afferent/Taste
Postcentral gyrus
nucleus tractus solitarius
nervus intermedius

geniculate ganglion
chord...
GANGLIA ASSOCIATED
WITH THE FACIAL NERVE
Geniculate ganglion
Submandibular ganglion
Pterygopalatine ganglion
Geniculate Ganglion
The geniculate ganglion (from Latin genu, for "knee") is
an L-shaped collection of fibers and sensory ...
Submandibular Ganglion
 The submandibular ganglion is small and fusiform
in shape. It is situated above the deep portion ...
Pterygopalatine Ganglion
The pterygopalatine ganglion (meckel's ganglion,
nasal ganglion or sphenopalatine ganglion) is a
...
Facial Nerve blood supply
The facial nerve gets it’s blood supply from 4 vessels:
 Anterior inferior cerebellar artery – ...
 Stylomastoid artery
(branch of posterior auricular artery) – mastoid
segment
 Posterior auricular artery supplies the f...
Variations of Facial Nerve
1. Buccal branch usually single, two branches in 15%
cases
2. Marginal mandibular branch – pass...
Patterns of branching of Facial Nerve
Classified by Davis et al (1956)
1. Type I facial nerve (straight branching) with variations.
Type IA

I). Zygomatic sending a loop to itself
ii). Absent z...
Type II facial nerve major connection between
buccal & zygomatic nerves
Type III facial nerve with major connection between
buccal & any other nerve.
Type IIIA
i). Anastomosis between zygomatic ...
Type IV Complex branching pattern.
Type IVA

i). Buccal nerve arising from upper division
ii). No anastomosis between bucc...
Type V Two main trunks.
i). Type VA
upper & lower division arising from major trunk,
buccal nerve arises from both divisio...
Variation of Marginal Mandibular branch
I)

The MMB showed one (28%), two (52%), three
(18%), or four branches (2%) where ...
Age Changes
Child

Adult

Chorda tympani may exit
through Stylomastoid Foramen

Chorda tympani exit proximal to
Stylomasto...
Testing of Facial Nerve Branches
 Testing the temporal branches of the facial nerve
To test the function of the temporal ...
 Testing the buccal branches of the facial nerve



Puff up cheeks (buccinator)



Smile and show teeth (orbicularis or...
 The marginal mandibular nerve may be
injured during surgery in the neck region,
especially during excision of the
subman...
Applied Surgical anatomy of
Facial Nerve in
Oral & Maxillofacial Surgery
 Damage to facial nerve is possible in severe
ma...
 After exiting the stylomastoid foramen, which is
situated posterolateral to stylomastoid process, the
nerve enters the s...
 The terminal branches of facial nerve then spread
in a fan like fashion as five separate nerves

 Temporal branch :
It ...
 Zygomatic Branch :
Its course is antero superior crossing the zygomatic
bone
Inadvertent damage may occur to this nerve ...
 Marginal mandibular branch:
It extends anteriorly and inferiorly within the substance
of parotid gland, there may be two...
The marginal mandibular branch is an important
structure encountered at the inferior border of the
mandible just beneath t...
 Cervical Branch:

The cervical branch exits the parotid gland
above its inferior pole and runs downwards
underneath the ...
 The surgeon must be mindful of the facial nerves
intimate involvement with the TMJ, specially when
performing surgical a...
Complications of parotid surgery
 Intra-operative or post-operative

 Post-operative complications can be classified as
...
Intra-operative complications of parotid gland surgery
 Intra-operative complications of parotid gland surgery
comprise t...
 The nerves are gently grasped with a Bishop forceps.
With an 8-0 nylon suture and a GS-8 needle, the
epineurium is grasp...
Post-operative complications of
parotid gland surgery
Post-operative facial nerve dysfunction involving some
or all of the...
The incidence of facial nerve paralysis is higher with
total, than with superficial parotidectomy, which may be
related to...
 However, eye protection must be ensured. If facial
paresis causes incomplete closure of the eye, the patient
must be adv...
Identification of Facial Nerve
3 surgical maneuvers used to identify nerve trunk
A. Blood free plane in front of external ...
Disorders of Facial Nerve
Facial Nerve Lesions
1. Supra nuclear type:
Features:
a)
b)
c)
d)

Paralysis of lower part of fa...
2. Nuclear type:
Features:
a) Paralysis of facial muscle (same side)
b) Paralysis of lateral rectus
c) Internal strabismus
3. Peripheral lesion
a) At internal acoustic meatus
Features:
i.
ii.
iii.
iv.
v.

Paralysis of secretomotor fibers
Hyper a...
Lesion at int
acoustic meatus
b) Injury distal to geniculate ganglion
Features:
i.
ii.
iii.
iv.
v.
vi.

Complete motor paralysis (same side)
No hyper ac...
Lesion
distal to
geniculate
ganglion
c) Injury at stylomastoid foramen
•

Condition known as Bell’s Palsy
Background of BELL’S PALSY
First described more than a
century ago by Sir Charles Bell

Yet much controversy still
surroun...
Demographics of Bells palsy
Race: slightly higher in persons of Japanese descent.
Sex: No difference exists
Age: highest i...
Pathophysiology of Bells palsy
Main cause of Bell's palsy is latent herpes viruses
(herpes simplex virus type 1 and herpes...
Inflammation of the nerve initially results in a
reversible neurapraxia

Herpes zoster virus shows more aggressive
biologi...
Features of Bell’s Palsy
I.

Unilateral involvement

II.

Inability to smile, close eye or raise eyebrow

III. Whistling i...
Fore head
Diagnosis of Bells palsy
By exclusion
Criteria
Paralysis or paresis of all muscle groups of one side of
the face
Sudden on...
Management of Bells palsy
Eye care
It focuses on protecting the cornea from drying and
abrasion due to problems with lid c...
Treatment consists of Infra-red radiation on affected
side of the face at 2 ft (60cm) ,followed by interrupted
galvanism ...
Medical treatment
Corticosteroids :
Prednisolone 1 mg/kg/day 7-10 days

Corticosteroids combine with antiviral drug is bet...
Surgical treatment
Facial nerve decompression
Indication:
Completely paralysis
ENoG less than 10% in 2 weeks
Appropriate t...
Causes of Facial Nerve Paralysis


Peripheral nerve causes (Facial muscle paralysis with
forehead affected)

 Lyme Disea...
 Central/Supranuclear causes
(Facial muscle paralysis with forehead spared)
 Cerebral mass lesion (e.g. tumor)

 Cerebr...
Traumatic causes
 Cortical injury
 Temporal BoneFracture
 Brain Stem injury
 Penetrating middle ear injury
 Barotraum...
Endocrine causes
 Diabetes Mellitus
 Hyperthyroidism
 Pregnancy
 Hypertension
 Alcohol Abuse (Alcoholic Neuropathy)
Infectious Causes


Malignant Otitis Externa (skull base Osteomyelitis)



Acute or Chronic Otitis Media
Gradenigo's Syn...
 HIV Infection
 Influenza Vaccine and Influenza
 Parotitis
 Meningitis or Encephalitis
 Mumps
 Mononucleosis
 Leprosy
 Coxsackie virus infection
 Syphilis
 Tuberculosis
 Botulism
 Mucormycosis
Causes due toTumors
 Facial Nerve neuroma
 Cholesteatoma
 Glomus jugular tumor
 Primary Temporal Bone tumors
 Meningi...
A tumor compressing the facial nerve result
in Facial paralysis
Birth Causes


Facial Nerve Injury from Birth Trauma



Trauma (forceps delivery)



Congenital Facial Palsy
Mobius syn...
Toxic Causes:


Thalidomide



Tetanus



Diphtheria



Carbon Monoxide



Lead Intoxication
Idiopathic Causes:


Myasthenia Gravis



Guillain-Barre Syndrome



Sarcoidosis



Familial Bell's Palsy
Iatrogenic Causes:


Antitetanus serum



Vaccine treatment for Rabies



Mandibular block anesthesia



Head and neck...
Evaluation of Facial paralysis
Clinical feature

Central VS Peripheral facial paralysis
Complete head and neck examination...
Central facial paralysis

Upper motor neuron lesion
Movements of the frontal and upper orbicularis oculi tend to be
spared...
Peripheral paralysis
Lower motor neuron lesion
At rest :
less prominent wrinkles on forehead of affected side, eyebrow
dro...
House-Brackmann grading system
Grade I - Normal
Grade II - Mild dysfunction, slight weakness on close
inspection, normal s...
Testing of Facial Nerve
TOPOGNOSTIC TESTING
1.
2.
3.
4.

Schirmer test for lacrimation (GSPN)
Stapedial reflex test (Stape...
Topographic Diagnosis
To determine the anatomical level of a peripheral lesion

Lacrimation

Stapedius reflex

Taste

Geni...
Schirmer's Test
Geniculate ganglion & petrosal nerve function test

Schirmer’s test +ve when
Affected side shows less than...
Schirmer's Test
Stapedius reflex
Nerve to stapedius muscle test

Impedence audiometry can record the presence or
absence of stapedius musc...
Taste (Electrogustometry)
Chorda tympani nerve test
Solution of salt, sugar, citrate, quinine or Electrical
stimulation
Co...
Maximum stimulation Test: MST:
Indication: complete paralysis<3wks

Interpretation:
Marked weakness or no muscle contracti...
Electroneurography: ENoG

Indication: complete paralysis<3wks

Interpretation: < 90% degeneration: prognosis is
good; > or...
Electromyography: EMG
Indication: Acute paralysis less than 1 week or chronic
paralysis longer than 2 weeks
Interpretation...
Herpes zoster oticus
Ramsay Hunt syndrome type II
Symptoms:
 Facial paralysis
 Ear pain
 Vesicles
 Sensorineural
heari...
Acute and chronic otitis media
Otitis media is an infection in the middle ear, which can
spread to the facial nerve and in...
Neurosarcoidosis
Facial nerve paralysis, sometimes bilateral, is a
common manifestation of neurosarcoidosis
(sarcoidosis o...
Congenital Facial nerve palsy
Moebius syndrome (congenital facial diplegia)
 Abnormal VI ,VII,XII Nerve nuclei
 Facial N...
Cardiofacial Syndrome
Unilateral facial paralysis involving only the lower lip
and congenital heart disease
 The facial p...
All are supplied by the mandibular marginal branch of
the facial nerve.
Lesions of this nerve have been recognized in adul...
Treacher collins syndrome
(mandibulo facial dysostosis)
There is a set of typical symptoms within Treacher Collins
Syndrom...
Facial Nerve involvement in
Treacher collins syndrome
N0: No facial nerve involvement
N1: Upper facial nerve involvement (...
Goldenhars syndrome
(oculoauriculo vertebral dysplasia)
It is a wide spectrum of congenital anomalies that
involves struct...
Conclusion
Surgeons have to pay attention to minimize the risk of
complication during parotidectomy.
The best means of red...
References
Fonseca & Walker : Maxillo FacialTrauma 2nd Edition
Vol 1 & 2
Grays Anatomy : 39th Edition
Netters : Colour Atl...
Guided by:
Dr.S.M.Nooruddin MDS.,
Professor & HOD
Dept of Oral & Maxillofacial Surgery
Dr.K.Surekha MDS.,
Associate Profes...
THANK YOU
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
Facial nerve ppt  roger original
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  1. 1. Contents 1. 2. 3. 4. 5. 6. 7. 8. Introduction Embryology Nuclei of origin Course & Relations Branches of facial nerve Functional components Ganglia associated with facial nerve Blood supply
  2. 2. 10.Variations of nerve 11.Testing of facial nerve 12.Identification of facial nerve 13.Complications of facial dissection 14.Facial nerve lesions 15.Acquired & Congenital anomalies
  3. 3. 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
  4. 4. Embryology  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
  5. 5.  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
  6. 6. 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
  7. 7. 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
  8. 8. 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
  9. 9. 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
  10. 10.  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
  11. 11. Nucleui of Origin 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.
  12. 12. 3. Nucleus 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. 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
  13. 13. Facial nerve origin
  14. 14. COURSE OF FACIAL NERVE Internal course: the motor fibres passes dorsally and medially forming a loop around the abducent nucleus in the floor of the 4th ventricle forming facial colliculus Superficial origin: at the pontomedullary angle above the inferior cerebellar peduncle.
  15. 15. The facial nerve is formed mainly of two parts: 1- Facial nerve proper (motor): arising from facial motor nucleus in pons. 2- Nervus intermedius: it is the sensory root of facial lies position between the facial proper and vestibulcochlear nerve in the pontocerebellar angle. Carrying para-sympathetic fibers (from superior salivary nucleus) and taste fibers ( to the solitary nucleus).
  16. 16. Course and relations: I- Intracranial (intrapetrosal) course II- Extracranial course
  17. 17. I- The intrapetrous course: The nerve passes laterally with the vestibulocochlear nerve (CN VIII) to the internal auditary meatus. At the bottom of the meatus the nerve enters the facial bony canal where it runs laterally above the vestibule of inner ear. Reaching the medial wall of the middle ear, it bends sharply backwards above the promontory (forming its genu) where the genicular ganglion is found It then arches downwards in the medial wall of the middle ear to reach the stylomastoid foramen.
  18. 18. II- Extracranial course:  As it emerges from the stylomastoid foramen, it runs forwards in the substance of the parotid gland crosses the styloid process, the retromandibular vein and the external carotid artery.  It divides behind the neck of the mandible into its terminal branches which come out of the anteromedial surface of the gland.
  19. 19. Branches Intracranial Greater petrosal nerve Nerve to stapaedius Chorda tympani Intratemporal Intrameatal Labyrinthine Tympanic Mastoid nerve
  20. 20. Extracranial Posterior Auricular Nerve Digastric nerve Stylohyoid nerve The five terminal branches Temporal branch Zygomatic branch Buccal branch Marginal mandibular branch Cervical branch
  21. 21.  Within the facial canal: 1- Nerve to stapedius: supplies the stapedius muscle.  2- Greater superfacial petrosal nerve (GSPN) : arises from the genicular ganglion The greater superficial petrosal nerve joins the deep petrosal nerve from the sympathetic plexus on the internal carotid artery in carotid canal to form the nerve of the pterygoid canal (vidian nerve) which passes through the pterygoid canal to the pterygopalatine fossa and ends in the pterygopalatine ganglion
  22. 22. 3- Chorda tympani nerve:  It arises from the facial nerve 6 mm above the stylomastoid foramen and runs upwards to perforate the posterior bony wall of the tympanic cavity.  It then passes forwards on the medial surface of the tympanic membrane between its fibrous and mucous layers crossing the handle of the malleus.
  23. 23.  It comes out of the tympanic cavity through the petrotympanic fissure to the infratemporal fossa where it joins the lingual nerve.  Through the lingual nerve, it supplies both the submandibular and sublingual salivary glands by secretomotor fibres and taste fibers from the anterior 2/3 of the tongue
  24. 24. II- At the exit from the stylomastoid foramen 1- Posterior auricular nerve: to the auricularis posterior and the occipital belly of the occipitofrontalis muscle. 2- Digastric branch: to the posterior belly of digastric muscle 3- Stylohyoid branch: to the stylohyoid muscle
  25. 25. TERMINAL BRANCHES The temporal branches of the facial nerve (frontal branch of the facial nerve) crosses the zygomatic arch to the temporal region, supplying the auricularis anterior and superior, and joining with the zygomaticotemporal branch of the maxillary nerve, and with the auriculotemporal branch of the mandibular nerve.
  26. 26. The more anterior branches supply the frontalis, the orbicularis oculi, and corrugator supercilii, and join the supraorbital and lacrimal branches of the ophthalmic. The temporal branch acts as the efferent limb of the corneal reflex.
  27. 27. The zygomatic branches of the facial nerve (malar branches) run across the zygomatic bone to the lateral angle of the orbit. Here they supply the Orbicularis oculi, and join with filaments from the lacrimal nerve and the zygomaticofacial branch of the maxillary nerve.
  28. 28. 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.
  29. 29. The buccal branch supplies these muscles MUSCLE ACTION Risorius Smile Buccinator Aids chewing by holding cheeks flat Levator Labii Superioris Elevates upper lip Levator labii superioris alaeque nasi Snarl Levator Anguli Oris Soft smile Nasalis Flare Nostrils Orbicularis oris muscle Purse Lips Depressor Septi Nasi Depresses Nasal Septum Procerus Moves Skin of Forehead
  30. 30.  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.
  31. 31.  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.
  32. 32. Branches Branches of communication Branches of distribution
  33. 33. Branches of Communication Internal acoustic meatus Geniculate ganglion Vestibulocochlear nerve A. Greater petrosal nerve B. Lesser petrosal nerve C. External petrosal nerve Facial canal Stylomastoid foramen Vagus nerve IX & X cranial nerve Greater auricular nerve Auriculotemporal nerve Behind ear Lesser occipital Face Neck V nerve Transverse cutaneous nerve
  34. 34. Branches of Distribution Facial canal A. Nerve to stapedius B. Chorda tympani Stylomastoid foramen A. Posterior auricular B. Nerve to stylohyoid C. Nerve to digastric (posterior belly) In face A. B. C. Temporal Zygomatic Buccal D. Marginal mandibular E. Cervical
  35. 35. Facial Nerve: Functional Components  Special Visceral Efferent/Branchial Motor  General Visceral Efferent/Parasympathetic  General Sensory Afferent/Sensory  Special Visceral Afferent/Taste
  36. 36. Special Visceral Efferent/Branchial Motor  Premotor cortex  motor cortex  corticobulbar tract  bilateral facial motor nuclei (pons)  facial muscles  Stapedius, stylohyoid, posterior digastric, buccinator
  37. 37. General Visceral Efferent/Parasympathetic Superior salivatory nucleus (pons) nervus intermedius greater/superficial petrosal nerve facial hiatus/middle cranial fossa joins deep petrosal nerve (symp fibers from cervical plexus) through pterygoid canal (as vidian nerve) pterygopalatine fossa spheno/pterygopalatine ganglion postganglionic parasympathetic fibers joins zygomaticotemporal nerve(V2) lacrimal gland & seromucinous glands of nasal and oral cavity
  38. 38. Superior salivatory nucleus nervus intermedius chorda tympani joins lingual nerve submandibular ganglion postganglionic parasympathteic fibers submandibular and sublingual glands
  39. 39. General Sensory Afferent/Sensory Sensation to auricular concha, EAC wall, part of TMJ, postauricular skin Through Cell bodies in geniculate ganglion
  40. 40. Special Visceral Afferent/Taste Postcentral gyrus nucleus tractus solitarius nervus intermedius geniculate ganglion chorda tympani joins lingual nerve anterior 2/3 tongue, soft and hard palate
  41. 41. GANGLIA ASSOCIATED WITH THE FACIAL NERVE Geniculate ganglion Submandibular ganglion Pterygopalatine ganglion
  42. 42. Geniculate Ganglion The geniculate ganglion (from Latin genu, for "knee") is an L-shaped collection of fibers and sensory neurons of the facial nerve located in the facial canal of the head. It receives fibers from the motor, sensory, and parasympathetic components of the facial nerve and sends fibers that will innervate the lacrimal glands, submandibular glands, sublingual glands, tongue, palate, pharynx, external auditory meatus, stapedius, posterior belly of the digastric muscle, stylohyoid muscle, and muscles of facial expression.
  43. 43. Submandibular Ganglion  The submandibular ganglion is small and fusiform in shape. It is situated above the deep portion of the submandibular gland, on the hyoglossus muscle, near the posterior border of the mylohyoid muscle.  The ganglion 'hangs' by two nerve filaments from the lower border of the lingual nerve (itself a branch of the mandibular nerve, CN V3). It is suspended from the lingual nerve by two filaments, one anterior and one posterior. Through the posterior of these it receives a branch from the chorda tympani nerve which runs in the sheath of the lingual nerve.
  44. 44. Pterygopalatine Ganglion The pterygopalatine ganglion (meckel's ganglion, nasal ganglion or sphenopalatine ganglion) is a parasympathetic ganglion found in the pterygopalatine fossa. It's largely innervated by the greater petrosal nerve (a branch of the facial nerve); and its axons project to the lacrimal glands and nasal mucosa
  45. 45. 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
  46. 46.  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
  47. 47. Variations of Facial Nerve 1. Buccal branch usually single, two branches in 15% cases 2. Marginal mandibular branch – pass bellow the lower border of mandible, incidence varying between 20-50% 3. Cervical branch – 20% cases, two branches  4. Katz and Catalano reported cases (3%) presenting two main trunks, known as the major and minor trunks of facial nerve.  5. Baker and Conley reported trifurcation, quadrifurcation, or even a plexiform branching pattern of the trunk of the facial nerve
  48. 48. Patterns of branching of Facial Nerve Classified by Davis et al (1956)
  49. 49. 1. Type I facial nerve (straight branching) with variations. Type IA I). Zygomatic sending a loop to itself ii). Absent zygomatic loop Type IB iii). Buccal nerve arising from upper division & mandibular sending a loop to itself iv). Mandibular loop is absent.
  50. 50. Type II facial nerve major connection between buccal & zygomatic nerves
  51. 51. Type III facial nerve with major connection between buccal & any other nerve. Type IIIA i). Anastomosis between zygomatic & buccal nerve ii). between buccal & upper division iii). between buccal and lower division Type IIIB iv). between buccal nerve (arising from mandibular) & zygomatic nerve Type IIIC v) Connection between buccal & marginal mandibular vi). Connection between buccal nerve arising from upper division & lower division . vii). Type III C with additional anastomosis between upper & lower divisions .
  52. 52. Type IV Complex branching pattern. Type IVA i). Buccal nerve arising from upper division ii). No anastomosis between buccal nerve & upper division (V). TYPE IVB iii). Buccal nerve arising from both division. iv). Buccal nerve arising from upper division only (V).
  53. 53. Type V Two main trunks. i). Type VA upper & lower division arising from major trunk, buccal nerve arises from both divisions, minor trunk joins lower division. ii). Type VB upper division from major & lower from minor trunk, buccal nerve arises from both division. iii). Type VC upper & lower division both arise from the major trunk & minor trunk enters the upper division as a separate branch.
  54. 54. Variation of Marginal Mandibular branch I) The MMB showed one (28%), two (52%), three (18%), or four branches (2%) where it exited the parotid gland. II) Type I (60%) did not communicate with other branches. Type II (40%) communicated with the buccal or cervical branches, or with another branch of the MMB III) The MMB pass the facial artery superficially (42%), deeply in 4%, and on both sides of it in 54% of the facial halves
  55. 55. Age Changes Child Adult Chorda tympani may exit through Stylomastoid Foramen Chorda tympani exit proximal to Stylomastoid Foramen 2nd genu is more acute and lateral 2nd genu is less acute and medial Nerve trunk is more anterior and lateral on exit through Stylomastoid Foramen Nerve trunk is less anterior and deeper Nerve very superficial over angle of mandible Nerve less superficial over angle of mandible
  56. 56. 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.
  57. 57.  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
  58. 58.  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.
  59. 59. Applied Surgical anatomy of Facial Nerve in Oral & Maxillofacial Surgery  Damage to facial nerve is possible in severe maxillofacial surgeries with basilar skull fractures anywhere in the area of course of the nerve and would result in ipsilateral paralysis of the muscles of facial expression  Of concern to the surgeon is the close proximity of the main trunk of facial nerve where it exits the stylomastoid foramen and mandibular condyle
  60. 60.  After exiting the stylomastoid foramen, which is situated posterolateral to stylomastoid process, the nerve enters the substance of parotid gland where it divides into its upper and lower divisions just posterior to the mandible  The approximate distance from the lowest pointof the external bony auditory meatus to the bifurcation of the facial nerve is 2.3 cm  Posterior to the parotid gland,the nerve is atleast 2cm deep into the skin surface,from this point the two branches curve around the posterior mandible,where they form plexus between the parotid gland and the masseter muscle
  61. 61.  The terminal branches of facial nerve then spread in a fan like fashion as five separate nerves  Temporal branch : It exits the parotid gland anterior to superficial temporal artery During an open approach to the TMJ, violation of this branch is possible
  62. 62.  Zygomatic Branch : Its course is antero superior crossing the zygomatic bone Inadvertent damage may occur to this nerve during open reduction of zygomatic arch or with the use of a byrd screw or zygomatic hook during closed approaches  Buccal Branch: It runs almost horizontally and will often divide into separate branch above and below parotid duct as it runs anteriorly Injury is possible in association with soft tissue trauma to the cheek region
  63. 63.  Marginal mandibular branch: It extends anteriorly and inferiorly within the substance of parotid gland, there may be two or three branches of this nerve. These branches run anteriorly parallel to inferior border of mandible and in some cases the course of the nerve is above the inferior border. In essentially all cases the nerve is located above the inferior border of mandible beyond the facial artery.
  64. 64. The marginal mandibular branch is an important structure encountered at the inferior border of the mandible just beneath the platysma muscle fibres during an open approach to the mandibular angle and body area. For this reason, an initial incision made approximately 1 to 1.5cm below the inferior border which prevents direct exposure or trauma to the nerve
  65. 65.  Cervical Branch: The cervical branch exits the parotid gland above its inferior pole and runs downwards underneath the platysma muscle
  66. 66.  The surgeon must be mindful of the facial nerves intimate involvement with the TMJ, specially when performing surgical approaches to the joint.  The temporal and zygomatic branches are at increased risk during pre auricular approach and the marginal mandibular branch during submandibular approach  The intra oral approach to the TMJ has minimal risk to the branches of facial nerve which is its major advantage
  67. 67. Complications of parotid surgery  Intra-operative or post-operative  Post-operative complications can be classified as early and late (or long-term) complications.
  68. 68. Intra-operative complications of parotid gland surgery  Intra-operative complications of parotid gland surgery comprise transection of the facial nerve or one of its branches, rupture of the capsule of a parotid tumour or incomplete surgical resection thereof.  The surgeon has to immediately recognize an intraoperative complication and management thereof must be performed without delay.  In the event of nerve injury, immediate nerve repair is mandatory. Once the segments have been fully mobilized and brought together without tension, the two ends should be sutured together.
  69. 69.  The nerves are gently grasped with a Bishop forceps. With an 8-0 nylon suture and a GS-8 needle, the epineurium is grasped at one end and then sutured to the other, avoiding deep cuts in the perineurium  Three sutures are usually adequate to maintain the anastomosis  As an alternative to sutures, the surgeon may use fibrin tissue adhesive.  If the nerve length is inadequate, a nerve graft of the greater auricular nerve, can be applied
  70. 70. Post-operative complications of parotid gland surgery Post-operative facial nerve dysfunction involving some or all of the branches of the nerve is the most frequent early complication of parotid gland surgery. Temporary facial nerve paresis, involving all or just one or two branches of the facial nerve, and permanent total paralysis have occurred. The cases of transient facial nerve paresis generally resolved within 6 months
  71. 71. The incidence of facial nerve paralysis is higher with total, than with superficial parotidectomy, which may be related to stretch injury or as result of surgical interference with the vasa nervorum The branch of the facial nerve most at risk for injury during parotidectomy is the marginal mandibular branch. Older patients appear to be more susceptible to facial nerve injury
  72. 72.  However, eye protection must be ensured. If facial paresis causes incomplete closure of the eye, the patient must be advised to use ophthalmic moisture drops frequently during the day and an ophthalmic ointment and eye protection at night.  Regular follow-up with an ophthalmologist is mandatory  Moreover, use of botulinum toxin to induce temporary ptosis avoids the need of surgical tarsorrhaphy.
  73. 73. Identification of Facial Nerve 3 surgical maneuvers used to identify nerve trunk A. Blood free plane in front of external acoustic meatus B. Exposure of anterior border of SCM below insertion into mastoid process C. Peripheral identification of terminal branch of facial nerve (marginal mandibular branch)
  74. 74. Disorders of Facial Nerve Facial Nerve Lesions 1. Supra nuclear type: Features: a) b) c) d) Paralysis of lower part of face (opposite side) Partial paralysis of upper part of face Normal taste and saliva secretion Stapedius not paralysed
  75. 75. 2. Nuclear type: Features: a) Paralysis of facial muscle (same side) b) Paralysis of lateral rectus c) Internal strabismus
  76. 76. 3. Peripheral lesion a) At internal acoustic meatus Features: i. ii. iii. iv. v. Paralysis of secretomotor fibers Hyper acusis Loss of corneal reflex Taste fibers unaffected Facial expression and movements paralysed
  77. 77. Lesion at int acoustic meatus
  78. 78. b) Injury distal to geniculate ganglion Features: i. ii. iii. iv. v. vi. Complete motor paralysis (same side) No hyper acusis Loss of corneal reflex Taste fibers affected Facial expression and movements paralysed Pronounced reaction of degeneration
  79. 79. Lesion distal to geniculate ganglion
  80. 80. c) Injury at stylomastoid foramen • Condition known as Bell’s Palsy
  81. 81. Background of BELL’S PALSY First described more than a century ago by Sir Charles Bell Yet much controversy still surrounds its etiology and management . Bell palsy is certainly the most common cause of facial paralysis worldwide
  82. 82. Demographics of Bells palsy Race: slightly higher in persons of Japanese descent. Sex: No difference exists Age: highest in persons aged 15-45 years. Bell palsy is less common in those younger than 15 years and in those older than 60 years.
  83. 83. Pathophysiology of Bells palsy Main cause of Bell's palsy is latent herpes viruses (herpes simplex virus type 1 and herpes zoster virus), which are reactivated from cranial nerve ganglia Polymerase chain reaction techniques have isolated herpes virus DNA from the facial nerve during acute palsy
  84. 84. Inflammation of the nerve initially results in a reversible neurapraxia Herpes zoster virus shows more aggressive biological behaviour than herpes simplex virus type1 Bell's phenomenon is the upward diversion of the eye ball on attempted closure of the lid is seen when eye closure is incomplete.
  85. 85. Features of Bell’s Palsy I. Unilateral involvement II. Inability to smile, close eye or raise eyebrow III. Whistling impossible IV. Drooping of corner of the mouth V. Inability to close eyelid (Bell’s sign) VI. Inability to wrinkle forehead VII. Loss of blinking reflex VIII.Slurred speech IX. Mask like appearance of face X. Loss/ alteration of taste
  86. 86. Fore head
  87. 87. Diagnosis of Bells palsy By exclusion Criteria Paralysis or paresis of all muscle groups of one side of the face Sudden onset Absence of signs of CNS disease Absence of signs of Ear disease
  88. 88. Management of Bells palsy Eye care It focuses on protecting the cornea from drying and abrasion due to problems with lid closure and the tearing mechanism. Lubricating drops should be applied hourly during the day and a simple eye ointment should be used at night.
  89. 89. Treatment consists of Infra-red radiation on affected side of the face at 2 ft (60cm) ,followed by interrupted galvanism on affected side Treatment was given daily at first few weeks & later thrice weekly. All patients are instructed to massage the face daily There is general agreement that 70-80% of these patients recover completely,while the reminder develop various sequelae within one to three months
  90. 90. Medical treatment Corticosteroids : Prednisolone 1 mg/kg/day 7-10 days Corticosteroids combine with antiviral drug is better Acyclovir 400 mg 5 times/day Famciclovir and valacyclovir 500 mg bid
  91. 91. Surgical treatment Facial nerve decompression Indication: Completely paralysis ENoG less than 10% in 2 weeks Appropriate time for surgery is 2-3 weeks after paralysis
  92. 92. Causes of Facial Nerve Paralysis  Peripheral nerve causes (Facial muscle paralysis with forehead affected)  Lyme Disease  Otits Media or Mastoiditis  Ramsay Hunt Syndrome  Autoimmune Polyneuropathy (e.g. Guillain-Barre Syndrome, typically bilateral)  Head or Neck Mass Lesion (e.g. Cholesteatoma)
  93. 93.  Central/Supranuclear causes (Facial muscle paralysis with forehead spared)  Cerebral mass lesion (e.g. tumor)  Cerebrovascular Accident (typically with ipsilateral Hemiparesis or Hemiplegia)  Multiple Sclerosis
  94. 94. Traumatic causes  Cortical injury  Temporal BoneFracture  Brain Stem injury  Penetrating middle ear injury  Barotrauma Altitude paralysis Scuba Diving
  95. 95. Endocrine causes  Diabetes Mellitus  Hyperthyroidism  Pregnancy  Hypertension  Alcohol Abuse (Alcoholic Neuropathy)
  96. 96. Infectious Causes  Malignant Otitis Externa (skull base Osteomyelitis)  Acute or Chronic Otitis Media Gradenigo's Syndrome (CN V or CN VI)  Mastoiditis  Varicella Zoster Virus (Chicken Pox)  Herpes Zoster Oticus (Ramsey-Hunt Syndrome) Herpetic Vesicles at auricle and external canal
  97. 97.  HIV Infection  Influenza Vaccine and Influenza  Parotitis  Meningitis or Encephalitis  Mumps  Mononucleosis
  98. 98.  Leprosy  Coxsackie virus infection  Syphilis  Tuberculosis  Botulism  Mucormycosis
  99. 99. Causes due toTumors  Facial Nerve neuroma  Cholesteatoma  Glomus jugular tumor  Primary Temporal Bone tumors  Meningiomas  Hemangioblastoma  Hemangioma  Pontine glioma  Parotid tumor
  100. 100. A tumor compressing the facial nerve result in Facial paralysis
  101. 101. Birth Causes  Facial Nerve Injury from Birth Trauma  Trauma (forceps delivery)  Congenital Facial Palsy Mobius syndrome Cardiofacial syndrome
  102. 102. Toxic Causes:  Thalidomide  Tetanus  Diphtheria  Carbon Monoxide  Lead Intoxication
  103. 103. Idiopathic Causes:  Myasthenia Gravis  Guillain-Barre Syndrome  Sarcoidosis  Familial Bell's Palsy
  104. 104. Iatrogenic Causes:  Antitetanus serum  Vaccine treatment for Rabies  Mandibular block anesthesia  Head and neck surgery
  105. 105. Evaluation of Facial paralysis Clinical feature Central VS Peripheral facial paralysis Complete head and neck examination Cranial nerve evaluation Electrodiagnostic testing Topographic diagnosis
  106. 106. Central facial paralysis Upper motor neuron lesion Movements of the frontal and upper orbicularis oculi tend to be spared Because of uncrossed contributions from ipsilateral supranuclear areas Involvement of tongue Involvement of lacrimation and salivation
  107. 107. Peripheral paralysis Lower motor neuron lesion At rest : less prominent wrinkles on forehead of affected side, eyebrow drop, flattened nasolabial fold, corner of mouth turned down Unable to : wrinkle forehead, raise eyebrow, wrinkle nasolabial fold, purse lips, show teeth, or completely close eye
  108. 108. House-Brackmann grading system Grade I - Normal Grade II - Mild dysfunction, slight weakness on close inspection, normal symmetry at rest Grade III - Moderate dysfunction, obvious but not disfiguring difference between sides, eye can be completely closed with effort Grade IV - Moderately severe, normal tone at rest, obvious weakness or asymmetry with movement, incomplete closure of eye Grade V - Severe dysfunction, only barely perceptible motion, asymmetry at rest Grade VI - No movement
  109. 109. Testing of Facial Nerve TOPOGNOSTIC TESTING 1. 2. 3. 4. Schirmer test for lacrimation (GSPN) Stapedial reflex test (Stapedial branch) Taste testing (Chorda tympani nerve) Salivary flow rates & pH (Chorda tympani) ELECTROPHYSIOLOGIC TESTS Nerve excitability test (NET) Electromyography(EMG) Maximal stimulation test (MST) Electroneuronography (ENoG) DYES
  110. 110. Topographic Diagnosis To determine the anatomical level of a peripheral lesion Lacrimation Stapedius reflex Taste Geniculate ganglion motor nerve of stapedius muscle chorda tympani
  111. 111. Schirmer's Test Geniculate ganglion & petrosal nerve function test Schirmer’s test +ve when Affected side shows less than half the amount of lacrimation seen on the normal side Sum of the lengths of wetted filter paper for both eyes less than 25 mm Lesion at or proximal to the geniculate ganglion
  112. 112. Schirmer's Test
  113. 113. Stapedius reflex Nerve to stapedius muscle test Impedence audiometry can record the presence or absence of stapedius muscle contraction to sound stimuli 70 to 100 db above hearing threshold An absence reflex or a reflex less than half the amplitude is due to a lesion proximal to stapedius nerve
  114. 114. Taste (Electrogustometry) Chorda tympani nerve test Solution of salt, sugar, citrate, quinine or Electrical stimulation Compares amount of current require for a response each side of tongue Normal : difference < 20 uAmp (thresholds differening by more than 25%= abnormal) Total lack of Chorda tympani : No response at 300 uAmp Disadvantage : False +ve in acute phase of Bell’s palsy
  115. 115. Maximum stimulation Test: MST: Indication: complete paralysis<3wks Interpretation: Marked weakness or no muscle contraction: advanced degeneration with guarded prognosis
  116. 116. Electroneurography: ENoG Indication: complete paralysis<3wks Interpretation: < 90% degeneration: prognosis is good; > or = 90%: prognosis is a question Limitation: False-positive results in deblocking phase.
  117. 117. Electromyography: EMG Indication: Acute paralysis less than 1 week or chronic paralysis longer than 2 weeks Interpretation: Active mu: intact motor axons Mu + fibrillation potentials: partial degeneration Polyphasic mu: regenerating nerve Limitation: cannot assess degree of degeneration or prognosis for recovery
  118. 118. Herpes zoster oticus Ramsay Hunt syndrome type II Symptoms:  Facial paralysis  Ear pain  Vesicles  Sensorineural hearing loss  Vertigo
  119. 119. Acute and chronic otitis media Otitis media is an infection in the middle ear, which can spread to the facial nerve and inflame it, causing compression of the nerve in its canal.
  120. 120. Neurosarcoidosis Facial nerve paralysis, sometimes bilateral, is a common manifestation of neurosarcoidosis (sarcoidosis of the nervous system).. Itself a rare condition.
  121. 121. Congenital Facial nerve palsy Moebius syndrome (congenital facial diplegia)  Abnormal VI ,VII,XII Nerve nuclei  Facial Nerve absent / smaller  Congenital Extra ocular muscle & facial palsy
  122. 122. Cardiofacial Syndrome Unilateral facial paralysis involving only the lower lip and congenital heart disease  The facial paralysis in these patients involves only those muscles concerned with pulling the lower lip downwards and outwards  These are the mentalis, depressor labii inferioris and depressor anguli oris muscles
  123. 123. All are supplied by the mandibular marginal branch of the facial nerve. Lesions of this nerve have been recognized in adults and children for many years The paralysis is only recognizable when the patient talks, smiles or cries
  124. 124. Treacher collins syndrome (mandibulo facial dysostosis) There is a set of typical symptoms within Treacher Collins Syndrome The OMENS classification was developed as a comprehensive and stage-based approach to differentiate the diseases. O; orbital asymmetry M; mandibular hypoplasia E; auricular deformity N; nerve development and S; soft-tissue disease
  125. 125. Facial Nerve involvement in Treacher collins syndrome N0: No facial nerve involvement N1: Upper facial nerve involvement (temporal or zygomatic branches) N2: Lower facial nerve involvement (buccal, mandibular or cervical) N3: All branches affected
  126. 126. Goldenhars syndrome (oculoauriculo vertebral dysplasia) It is a wide spectrum of congenital anomalies that involves structures arising from the first and second branchial arches. Features of hemi facial microsomia, anotia, vertebral anomalies, congenital facial nerve palsy.
  127. 127. Conclusion Surgeons have to pay attention to minimize the risk of complication during parotidectomy. The best means of reducing iatrogenic facial nerve injury, in parotid surgery, still remains a clear understanding of the anatomy, good surgical technique with the use of multiple anatomic landmarks. Pre-operative discussion and consent for surgery, tailored according to the age and health of the patient as well as the behavior of the tumor, are mandatory Furthermore, the patient has to be informed about the cosmetic sequelae of the incision and all patients have to be told that facial nerve paralysis or paresis is possible and can be partial or total, temporary or permanent.
  128. 128. References Fonseca & Walker : Maxillo FacialTrauma 2nd Edition Vol 1 & 2 Grays Anatomy : 39th Edition Netters : Colour Atlas of Anatomy International journal of Oral & maxillofacial Surgery
  129. 129. Guided by: Dr.S.M.Nooruddin MDS., Professor & HOD Dept of Oral & Maxillofacial Surgery Dr.K.Surekha MDS., Associate Professor Dr.G.Sudhakar MDS., Assistant Professor Presented by: Dr.T.Roger paul 1st yr PG GDC&H, VIJAYAWADA.
  130. 130. THANK YOU

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