Osteology of Maxilla and Mandible , Facial nerve
CHAITANYA.PI MDSDept of Public Health Dentistry
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Previous questions
1. Osteology of maxilla and mandible(2times)2. Facial nerve (3times)20Mark
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abbrevations
• Sensory – carry impulse from receptor site to brain• Motor- carry impulse form brain to receptor site• Ponto cerebellar angle – junction between pons
and cerebellum• Osteomyelitis- dead bone.• Ganglion – collection of nerve fibers• Tympanic membrane which separates outer and
middle ear cavity
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Maxilla• It is the second largest bone of the face• It forms the upper jaw with the fellow of the
opposite side• It also contributes to the formation of1. Floor of the nose and the orbit2. Roof of the mouth3. Lateral wall of the nose4. Pterigopalatine and infratemporal fossae5. Pterigomaxillary and infraorbital fissures
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Alveolar process
Orbital process
Zygomatic process
Palatine process
Nasal process
Anatomy of the maxilla
• The anatomy of the maxilla has two main parts:1. Body(pyramidal shape)
– Anterior surface– Posterior surface– Orbital surface– Nasal surface
2. Processes– Zygomatic– Frontal– Alveolar– Palatine
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Processes
• Zygomatic: it is rough and pyramidal
– Front: It is continuous with the anterior surface of body
– Behind(concave):in continuity of the posterior surface
– Above: articulates with zygomatic bone
– Below(arched border) which anterior and posterior surface
of the body
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• Frontal Process:– Lateral Surface: • Vertical ridge (Lacrimal crest)• Groove for the lacrimal sac
– Medial surface: It is rough and uneven and articulates with the ethmoid and also closes the anterior ethmoidal sinus below ethmoidal crest• Upper end: Articulates with the frontal bone• Anterior border with the nasal bone• Posterior border with the lacrimal bone
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• Alveolar processes: It has thick arched border behind
and contains sockets to receive roots of teeth which vary in
size and depth
– Canine deepest
– Molar widest and subdivided into 3 minor sockets by septae
– Incisors and premolars single
– Occasionally incisors are divided into 2 sockets
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• Palatine Process: Thick strong horizontal
– Inferior surface is concave and presents numerous foramina for
passage of nutrient vessels and contains depressions for
lodgement of glands
– Groove for greater palatine Vessels and nerves
– Incisive fossa leads into the incisive canal
– Upper surface: forms the floor of the nasal cavity
– Lateral Border fuses with rest of the bone
– Posterior border fuses with the horizontal plate of the palatine
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Arterial supply
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Gray’s Anatomy,40th edition, pg.no:477-484, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:77-80, 2010,Lippincott Williams & Wilkins publishers. Netter’s Head and Neck Anatomy for Dentistry, 2nd Edition, pg.no:43-46, 2012 Elsevier publisher.
Maxillary Artery
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Nerve Supply
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Age changes in Maxilla
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Gray’s Anatomy,40th edition, pg.no:477-484, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:77-80, 2010,Lippincott Williams & Wilkins publishers. Netter’s Head and Neck Anatomy for Dentistry, 2nd Edition, pg.no:43-46, 2012 Elsevier publisher.
Mandible• Largest and strongest bone of the face• Curved horizontal body; convex forwards• It has two rami which project upward from
posterior end of the body• The body is horse shoe shaped
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Borders• Upper boder:– Sockets for the mandibular teeth are present
• Lower border(Base) presents a digastric fossa• Ramus– Lateral Surface– Medial Surface
• Mandibular foramen canal• Lingula- mylohyoid groove
• Inferior border is continuous with the angle of mandible
• Upper Border: Mandibular Notch20
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Internal Surface
• Mylohyoid line• Sub mandibular fossa• Sub lingual fossa• Genial tubercle• Mylohyoid groove
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Gray’s Anatomy,40th edition, pg.no:477-484, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:77-80, 2010,Lippincott Williams & Wilkins publishers. Netter’s Head and Neck Anatomy for Dentistry, 2nd Edition, pg.no:43-46, 2012 Elsevier publisher.
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Gray’s Anatomy,40th edition, pg.no:477-484, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:77-80, 2010,Lippincott Williams & Wilkins publishers. Netter’s Head and Neck Anatomy for Dentistry, 2nd Edition, pg.no:43-46, 2012 Elsevier publisher.
Age changes in mandible
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Applied anatomy Maxillary
1. Maxillary clefts 2. Traumatic extractions
leads to # of the bone. 3. dental caries leading
to osteomyelitis
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A. P. Armstrong and N. Waterhouse, Tessier 30 median mandibular cleft: case report and literature review, British Journal of Plastic Surgery (1996), 49, pg.no:536-538Maria Costanza Meazzini et al, Long-term follow-up of large maxillary advancements with distraction osteogenesis in growing and non-growing cleft lip and palate patients, Journal of Plastic, Reconstructive & Aesthetic Surgery (2015) 68, 79-86
Mandibular1. Mandibular clefts2. Traumatic
extractions leads to angular # and dislocation of the TMJ
3. TMJ ankylosis
FACIAL NERVE
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1. Introduction
2. Embryology
3. Nuclei of origin
4. Course & Relations
5. Branches of facial nerve
6. Functional components
Contents
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7. Ganglia associated with facial nerve
8. Blood supply
9. Facial nerve lesions
10.Acquired & Congenital anomalies
11.Conclusion
12.References
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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 fibers to
several head and neck ganglia36
Embryology
The facial nerve is developmentally derived from the hyoid
arch, which is the second brachial 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
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
Nuclei 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.
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
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 :
These fibers communicates to acoustic meatus & back of auricle
and aslo communicates to auricular branch of vagus. These
fibers terminate in main sensory nucleus & spinal nucleus of 5th
nerve 39
Facial nerve origin40
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.
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
1- Facial nerve proper (motor): arising from facial motor
nucleus in pons.
2- Nervus intermedius: it is the sensory root of facial, lies
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).
The facial nerve is formed mainly of two parts:
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Course and relations: I- Intracranial (intrapetrosal) course
II- Extracranial course
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
I- The Intrapetrous course:
• The nerve passes laterally with the vestibulocochlear nerve
(CN VIII) to the internal auditory 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 geniculate ganglion is found.
• It then arches downwards in the medial wall of the middle
ear to reach the stylomastoid foramen.
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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.
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
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Intracranial
Greater petrosal nerveNerve to stapaediusChorda tympani
Intratemporal
IntrameatalLabyrinthineTympanicMastoid nerve
Branches
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Extracranial
Posterior Auricular NerveDigastric nerveStylohyoid nerve
The five terminal branches
Temporal branchZygomatic branchBuccal branchMarginal mandibular branchCervical branch
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
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Netter’s Head and Neck Anatomy for Dentistry,
2nd Edition, pg.no: 94, 2012 Elsevier publisher
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
The Buccal branch supplies these muscles
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
Branches
Branches of communication Branches of distribution
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Internal acoustic meatus Vestibulocochlear nerveGeniculate ganglion A. Greater petrosal nerve
B. Lesser petrosal nerve C. External petrosal nerve
Facial canal Vagus nerve Stylomastoid foramen IX & X cranial nerve
Greater auricular nerveAuriculotemporal nerve
Behind ear Lesser occipital Face V nerve Neck Transverse cutaneous nerve
Branches of Communication
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Branches of Distribution
Facial canal A. Nerve to stapediusB. Chorda tympaniC. Greater petrosal nerve
In face A. TemporalB. Zygomatic C. Buccal D. Marginal mandibularE. Cervical
Stylomastoid foramenA. Posterior auricularB. Nerve to stylohyoidC. Nerve to digastric
(posterior belly)
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GANGLIA ASSOCIATED WITH THE FACIAL NERVE
Geniculate ganglion
Submandibular ganglion
Pterygopalatine ganglion
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Geniculate Ganglion
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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.
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
Submandibular Ganglion
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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.
61Netter’s Head and Neck Anatomy for Dentistry, 2nd Edition, pg.no: 93-94, 2012 Elsevier publisher
Pterygopalatine Ganglion
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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
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
• 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
Facial Nerve blood supply
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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
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
Disorders of Facial Nerve
1. Supra nuclear type:
Features:
a) Paralysis of lower part of face (opposite side)
b) Partial paralysis of upper part of facec) Normal taste and saliva secretiond) Stapedius not paralysed
Facial Nerve Lesions
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2. Nuclear type:
– Features:
a) Paralysis of facial muscle (same side)
b) Paralysis of lateral rectus
c) Internal strabismus
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
3. Peripheral lesion
a) At internal acoustic meatus
Features:
i. Paralysis of secretomotor fibersii. Hyperacusis iii. Loss of corneal reflexiv. Taste fibers unaffected v. Facial expression and movements paralyzed
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b) Injury distal to geniculate ganglion
Features:
i. Complete motor paralysis (same side)ii. No hyperacusis iii. Loss of corneal reflexiv. Taste fibers affected v. Facial expression and movements paralyzedvi. Pronounced reaction of degeneration
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• Condition known as Bell’s Palsy
c) Injury at Stylomastoid foramen
• First described more than a century ago by Sir Charles Bell
• Bell palsy is certainly the most common cause of facial paralysis worldwide
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
• 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.
Pathophysiology of Bells palsy
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010,Lippincott Williams & Wilkins publishers.James A. McCau et al, Evidence based management of Bell’s palsy, British Journal of Oral and Maxillofacial Surgery 52 (2014) 387–39.W.M. Morris, SURGICAL TREATMENT OF BELL'S PALSY, The Lancet, vol 231, Issue5973, 19 feb 1938, pg: 429-431
• 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. 73
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
Features of Bell’s Palsy
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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
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• 0.5mg gold plating in eye lid • Sural nerve grafting
Surgical treatment
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010,Lippincott Williams & Wilkins publishers.James A. McCau et al, Evidence based management of Bell’s palsy, British Journal of Oral and Maxillofacial Surgery 52 (2014) 387–39.W.M. Morris, SURGICAL TREATMENT OF BELL'S PALSY, The Lancet, vol 231, Issue5973, 19 feb 1938, pg: 429-431
Birth Causes
Facial Nerve Injury from Birth Trauma
Trauma (forceps delivery)
Congenital Facial Palsy
Mobius syndrome
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
INFECTIOUS CAUSES
Malignant Otitis Externa (skull base
Osteomyelitis)
Mastoiditis
Varicella Zoster Virus (Chicken Pox)
Herpes Zoster Oticus (Ramsey-Hunt
Syndrome)
Parotitis
Meningitis or Encephalitis
Mumps
Mononucleosis
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Gray’s Anatomy,40th edition, pg.no:1142-1143, 2008, Churchill living stone Elsevier publisher.James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:146-151, 2010, Lippincott Williams & Wilkins publishers
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• Maxilla and mandible forms a major part of face.
• Defects in osteogenesis may lead to clefts and facial
abnormalities
• Facial nerve plays major in role in facial expressions and also
for taste sensation any damage to maxilla, mandible and
parotid gland may lead to facial nerve paralysis.
• To diagnose and treat the defects one should have thorough
idea on development of these stuctures.
Conclusion
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1. Gray’s Anatomy,40th edition, pg.no:477-484 & 1142-1143, 2008, Churchill living stone Elsevier publisher.
2. James L. Hiatt & Leslie P. Gartner, Text book of head and neck anatomy, 4th edition, pg no:77-80 & 146-151, 2010,Lippincott Williams & Wilkins publishers.
3. James A. McCau et al, Evidence based management of Bell’s palsy, British Journal of Oral and Maxillofacial Surgery 52 (2014) 387–39.
4. W.M. Morris, SURGICAL TREATMENT OF BELL'S PALSY, The Lancet, vol 231, Issue5973, 19 feb 1938, pg: 429-431
Reference
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5. Netter’s Head and Neck Anatomy for Dentistry, 2nd Edition, pg.no:43-46 & 93-94, 2012 Elsevier publisher.
6. Nelson Álvares Cruz Filho et al Facial nerve grafting and end-to-end anastomosis in the middle ear - tympanic cavity and mastoid Brazilian Journal of Otorhinolaryngology 79 (4) pg.no: 441-445, July/August 2013 .
7. Maria Costanza Meazzini et al, Long-term follow-up of large maxillary advancements with distraction osteogenesis in growing and non-growing cleft lip and palate patients, Journal of Plastic, Reconstructive & Aesthetic Surgery (2015) 68, 79-86
8. A. P. Armstrong and N. Waterhouse, Tessier 30 median mandibular cleft: case report and literature review, British Journal of Plastic Surgery (1996), 49, pg.no:536-538
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