5.osteology of maxilla and mandible, facial nerve

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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Venous drainage

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http://www.google.co.in/url?sa=i&rct=j&q=veinous+drainage+of+maxilla&source=images&cd=&cad=rja&docid=UIT9XjcyHmqFgM&tbnid=EjuETL7ts-iacM:&ved=0CAUQjRw&url=http://www.studyblue.com/notes/note/n/neuro-final-anatomy/deck/5296102&ei=X6RwUYveOofprAfRi4HADw&bvm=bv.45373924,d.bmk&psig=AFQjCNGozP1hlxG-3qMqOTqLA99w0W5iUA&ust=1366423003389787

Nerve Supply

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Age changes in Maxilla

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http://www.google.co.in/url?sa=i&rct=j&q=ossification+centers+in+maxilla&source=images&cd=&cad=rja&docid=McxXncGe05t1VM&tbnid=eweTf071iiMtrM:&ved=0CAUQjRw&url=http://en.wikipedia.org/wiki/Ossification_of_maxilla&ei=z6dwUa29MYfVrQe8w4CADA&psig=AFQjCNGIv-btgC1zUXZzz7xx8aBoFsCGgA&ust=1366423885399035

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

Internal Surface

• Mylohyoid line• Sub mandibular fossa• Sub lingual fossa• Genial tubercle• Mylohyoid groove

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Arterial Supply of Mandible

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http://www.google.co.in/url?sa=i&rct=j&q=arterial+supply+of+mandible&source=images&cd=&cad=rja&docid=e-aUVOJcxKLITM&tbnid=Qx83B1f2bxxN8M:&ved=0CAUQjRw&url=http://en.m.wikipedia.org/wiki/Inferior_alveolar_artery&ei=FKZwUd2-E9HOrQfbqICIDA&psig=AFQjCNGXy7r4XlXhrxzyUf5eaptiz1XA4A&ust=1366423405847362

Nerve supply of Mandible

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http://www.google.co.in/url?sa=i&rct=j&q=nerve+supply+of+mandible&source=images&cd=&cad=rja&docid=Hl1sdSRycYAm2M&tbnid=exO5KurceFNRtM:&ved=0CAUQjRw&url=http://www.pitt.edu/~regional/Dental%20Blocks/dental%20blocks.htm&ei=ZaZwUfj4AorIrQexvYCoDw&psig=AFQjCNH1zYbATQ27I6FS3HW_wycKK7kAzg&ust=1366423515300591

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http://www.google.co.in/url?sa=i&rct=j&q=nerve+supply+of+mandible&source=images&cd=&cad=rja&docid=vfdHs6eSPqNidM&tbnid=FRyyb9ZUDLN8lM:&ved=0CAUQjRw&url=http://www.sciencedirect.com/science/article/pii/S000399691100286X&ei=iaZwUZvQC4TtrAeZq4GQAQ&psig=AFQjCNH1zYbATQ27I6FS3HW_wycKK7kAzg&ust=1366423515300591

http://www.google.co.in/url?sa=i&rct=j&q=nerve+supply+of+mandible&source=images&cd=&cad=rja&docid=vfdHs6eSPqNidM&tbnid=9jWsuB1psLD2VM:&ved=0CAUQjRw&url=http://www.sciencedirect.com/science/article/pii/S000399691100286X&ei=kqZwUaDeA8KKrQeS1ICwCQ&psig=AFQjCNH1zYbATQ27I6FS3HW_wycKK7kAzg&ust=1366423515300591

Venous drainage of Mandible

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http://www.google.co.in/url?sa=i&rct=j&q=veins++of+mandible&source=images&cd=&cad=rja&docid=BcxTe5mOkY9ftM&tbnid=cS3jDvEV0bmzjM:&ved=0CAUQjRw&url=http://www.studyblue.com/notes/note/n/head-semi-random/deck/4635344&ei=LadwUeHOIcmOrge8jYCgCg&psig=AFQjCNGTSpEio0lhzSUPeLbz4D8vMtBTYw&ust=1366423713915808

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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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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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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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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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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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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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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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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• 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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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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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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• 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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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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• 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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5.osteology of maxilla and mandible, facial nerve

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