anatomy of head and neck nerve supply and lymphatic drainage

ANATOMY OF HEAD AND NECK NERVE SUPPLY AND LYMPHATIC SUPPLY

MADE BY-AMIT BHARGAVAMDS PROSTHODONTICS (1ST YR)

CONTENTS

NERVOUS SYSTEM• Functions of nervous tissue• Classification of nervous systems• Anatomical course of cranial nerveLYMPHATIC DRAINAGE• Structure• Anatomical distribution• Site specific drainage• Clinical correlations

INTRODUCTION TO NERVOUS SYSTEM

• The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions and transmit signals between different parts of its body

FUNCTIONS OF NERVOUS TISSUE::• Sense stimuli in both internal and external environment.

• Stimuli are analysed & integrated to provide co-ordinated responses

• Sensory neurons transmit impulses from sense organs to CNS

• Connector neurons supply connection between sensory and motor

neurons.

• Efferent(somatic) neurons transmit impulses from CNS to a muscle.

• Efferent(autonomic) neurons transmit impulses to a involuntary

muscle or gland.

ALL THE FUNCIONS ARE ACHIEVED BY THREE NERVOUS SYSTEMS OF THE BODY:

1. Central nervous system

2. Peripheral nervous system

3. Autonomic nervous system

CENTRAL NERVOUS SYSTEM• Central nervous system composed

of brain and spinal cord

Has 4 parts:• Spinal cord• Rhombencephalon ( medulla, pons, cerebellum)• Mesencephalon (midbrain)• Prosencephalon (forebrain)

12 PAIRS OF CRANIAL NERVES31 PAIRS OF SPINAL NERVES

PERIPHERAL NERVOUS SYSTEM• The peripheral nervous system consists of the nerves and outside of the

brain and spinal cord.

• function - connect the central nervous system to the limbs and organs.

AUTONOMIC NERVOUS SYSTEMConsists of sensory and motor neurons that run in between the

central nervous system and the internal organs.

2 divisions::1. Sympathetic2. parasympathetic

LIST OF CRANIAL NERVES

I Olfactory nerve SensoryII Optic nerve SensoryIII Occulomotor nerve MotorIV Trochlear nerve MotorV Trigeminal nerve Opth.-Sensory Max.-Sensory Mand.-MixedVI Abducent nerve MotorVII Facial nerve MixedVIII Auditory nerve SensoryIX Glossopharyngeal nerve MixedX Vagus nerve MixedXI Spinal accessory nerve Motor XII Hypoglossal Nerve Motor

OLFACTORY NERVE

OLFACTORY NERVE

• Sensory in nature.

• Originates in upper nasal concha and

superior part of nasal septum.

• Ends in medial surface of cerebral

hemisphere & temporal lobe.

OLFACTORY NERVE

COURSE

• Dissolution of inhaled

aromatic molecules in the

mucous lining olfactory

epithelial cells and

stimulation of its

chemoreceptors.

• Exaggeration of the action potential by olfactory receptor cells

• Pass through cribriform plate of ethmoid bone to synapse in secondary sensory neurons in olfactory bulb

• Amygdala

OLFACTORY NERVE

APPLIED ANATOMY

• Smell is responsible for finer appreciation of taste.LOSS OF SMELL OR ANOSMIA:CAUSES

1. HEAD INJURIES: Sudden shift of cerebral hemisphere results in avulsion

of olfactory bulb from brain.

2. FRACTURE OF CRIBRIFORM PLATE: May lead to damage to olfactory

nerve and CSF rhinorrhoea.

3. TUMOURS: Tumours of the frontal lobe or those arising near the

pitutary gland may cause pressure symptoms on olfactory tract.

4. CHRONIC TUBERCULOUS MENINGITIS

ROLE IN PROSTHODONTICS

1.Cobalt–chromium–nickel damages nasal cells

due to complex of carnosine with metal

2. methyl methacrylate-methacrylic acid.

N Torbica, S Krstev World at work: Dental laboratory technicians.Occup Environ

Med2006;63:145-148

OPTIC NERVE

OPTIC NERVE

• Sensory nerve

• Not a peripheral nerve.

• Extension of the white matter of

brain

• Responsible for vision• The optic nerve is a continuation of

the axons of the ganglion cells in the

retina.

COURSE

• Begins the back of

the eye

• Joins optic

chiasma in cranial

cavity.

• Extends to lateral

geniculate nucleus in thalamus forming optic tract.

• Ends in visual cortex area in occiptal lobe

OPTIC NERVE

APPLIED ANATOMY OF OPTIC TRACT

• LESION OF OPTIC NERVE:

A) Total blindness of the corresponding eye.

B) Loss of pupillary light reflex on the affected side and consensual reflex on the

sound side.

• WHEN A TUMUOR AFFECTS THE BASE OF FRONTAL LOBE , IT MAY PRESS

UPON OPTIC NERVE:

Optic atrophy on the affected side, due to pressure.

• ARGYLL-ROBERTSON PUPIL– specific sign of neurosyphilis.

- Loss of light reflex but the near reflex is retained.

ROLE IN PROSTHODONTICS • eye prosthesis - to treat anopthalmous detailed anatomyshould be kept in mind.• Enucleation ,Evisceration

Dr. Kalavathi S.D Restoring Ocular Esthetics Using Ocular Prosthesis Journal of Dental Sciences & Research 1:2: Pages 39-44

OCULOMOTOR NERVE

OCCULOMOTOR NERVE

• Motor in nature

• Supplies all the extra ocular muscles,

except superior oblique and lateral rectus.

• Supplies sphincter pupillae and cilliaris

muscle

OCCULOMOTOR NERVE

DEEP ORIGIN (NUCLEAR ORIGIN)

Ventro medial part of the

periaqueductal central grey

matter of the midbrain

OCCULOMOTOR NERVE

COURSE AND RELATIONSFrom the superficial origin, piamater (passes in between,Post. & sup. Cerebellar arteries Pierces arachnoid

Mater) duramater cavernous sinus

superior orbital fissure within tendinous ring.

OCCULOMOTOR NERVE

APPLIED ANATOMY:

COMPLETE DIVISION OF OCCULOMOTOR NERVE ON ONE SIDE

a) Ptosis or drooping of the upper eyelid- paralysis of leavator palpebrae superioris

b) External strabismus(squint)- unopposed action of lateral rectusc) Dilated or fixed pupild) Loss of accommodatione) Apparent protrusion of eyeball- flaccid paralysis of ocular muscles.f) Diplopia- where false image is higher than true image.

TROCHLEAR NERVE

TROCHLEAR NERVE

• Motor in nature

• Nerve with the longest

intracranial course.

• Supplies -superior

oblique muscle.

TROCHLEAR NERVE

DEEP ORIGIN:

• Periaqueductal grey

mater of the midbrain

at level of

inf. colliculus• Lies at level of

ventro medial nucleus

of 3rd nerve.

.

TROCHLEAR NERVE

COURSE

trochlear nucleus,

duramater,

lateral wall of cavernous sinus.

Superior orbital fissure

outside tendinous ring.

TROCHLEAR NERVE

APPLIED ANATOMY

IF TROCHLEAR NERVE IS INJURED

• Patient is unable to turn his eye downward and laterally.• NO difficulty in looking above horizontal plane.• On attempting to look down, double vision is seen.• To avoid, patient tilts his head forwards towards the sound

side.

TRIGEMINAL NERVE

TRIGEMINAL NERVE

• fifth cranial nerve• mixed in nature• It is the largest of the cranial nerves• Nuclei – 4 nuclei – 1 motor and 3 sensory

TRIGEMINAL NERVE

GASSERION GANGLION

• Also known as semilunar ganglion• Developed from neural crest.• Crescent shaped.• Located in meckel’s cavity.• Forms: Central processes Peripheral processes

TRIGEMINAL CAVE

TRIGEMINAL NERVE

SENSORY ROOT OF TRIGEMINAL NERVE Fibres arise from the semilunar ganglion. Enter brainstem through side of pons.

TRIGEMINAL NERVE

SENSORY ROOT OF TRIGEMINAL NERVE Fibres arise from the semilunar ganglion. Enter brainstem through side of pons.

CENTRAL BRANCHES (SENSORY ROOTS OF NERVE)

ASCENDING FIBRES DESCENDING FIBRES

TRIGEMINAL NERVE

SENSORY ROOT OF TRIGEMINAL NERVE Fibres arise from the semilunar ganglion. Enter brainstem through side of pons.

CENTRAL BRANCHES (SENSORY ROOTS OF NERVE)

ASCENDING FIBRES DESCENDING FIBRES

Terminate in UPPER sensory nucleusIn pons lateral to motor nucleus. DORSAL TRIGEMINO-THALAMIC TRACT

CONVEY::Light touch Tactile discrimination Sense of positionPassive movement

TRIGEMINAL NERVE

SENSORY ROOT OF TRIGEMINAL NERVE Fibres arise from the semilunar ganglion. Enter brainstem through side of pons.

CENTRAL BRANCHES (SENSORY ROOTS OF NERVE)

ASCENDING FIBRES DESCENDING FIBRES

Terminate in UPPER sensory nucleus Terminate in SPINAL nucleus extending In pons lateral to motor nucleus. Caudally from upper sensory nucleus to . 2nd cervical segment.

CONVEY:: CONVEY::Light touch PainTactile discrimination TemperatureSense of positionPassive movement

TRIGEMINAL NERVE

PERIPHERAL BRANCHES

OPTHALMIC nerve

MAXILLARY nerve

MANDIBULAR nerve

TRIGEMINAL NERVEOPTHALMIC DIVISION:Sensory in nature.

Route: Leaves the anterior medial part of the ganglion and passes forward in the lateralpart of cavernous sinus.

Fibres are afferent to:• Scalp• Skin of forehead• Upper eyelid lining the frontal sinus• Conjunctiva of eyeball• Lacrimal gland• Skin of lateral angle of the eye• sclera of eyeball• Lining of ethmoid cells

TRIGEMINAL NERVE

SUBDIVISIONS

• LACRIMAL NERVE• FRONTAL NERVE• NASOCILLIARY NERVE

TRIGEMINAL NERVE

LACRIMAL NERVE::

• Smallest of the three branches.

Passes into orbit at lateral angle of

superior orbital fissure.

• Courses anterolaterally to reach

lacrimal gland.

• SUPPLIES

Lacrimal Gland &Adjacent Conjunctiva.

TRIGEMINAL NERVE

FRONTAL NERVE: (LARGEST OF THREE)

• In middle of orbit, nerve divides into:

SUPRA ORBITAL NERVE: SUPRA TROCHLEAR NERVE:Largest branch Smallest BranchLeaves orbit through Supra orbital foramen. Pierces fascia of upper eyelid.

SUPPLIES: SUPPLIES:• Skin of upper eyelid • Ant. Scalp region to vertex of skull

• Skin Of The Upper Eyelid• Lower medial portion of forehead

TRIGEMINAL NERVE

NASOCILIARY NERVE::• Enters the orbit through superior orbital fissure.• Supply- mucous membrane of the nose - the tip of the nose - the conjunctiva.

TRIGEMINAL NERVE

MAXILLARY DIVISION• SENSORY IN NATURE

• 2nd division of the trigeminal

nerve.

Tansmits afferent impulses from:• Upper lip

• Lower eyelid

• Tonsillar region

• Side of the nose

• Hard and soft palate

• Lining of maxillary sinus

• Opening of eustachian tubes

• All maxillary teeth and gingiva

• Mucous membrane of the nasal cavity

TRIGEMINAL NERVE

COURSE:Intracranial part::• Originates in the middle part of semilunar ganglion• Passes forward in lower part of cavernous sinus• Exits through foramen rotundum.

TRIGEMINAL NERVE

Extracranial part::• Enters pterygopalatine fossa.• Enters inferior orbital fissure to enter orbital cavity.• Runs laterally along infra orbital groove.• Emerges through infra orbital foramen.

BRANCHES OF MAXILLARY NERVEBRANCHES IN

MIDDLE CRANIAL FOSSA

BRANCHES IN PTERYGOPALATINE

FOSSA

BRANCHES IN INFRAORBITAL GROOVE

AND CANAL

TERMINAL BRANCHES ON FACE

MIDDLE MENINGEALNERVE

• ZYGOMATIC• SPHENOPALATINE

• POSTERIOR SUPERIOR ALVEOLAR

• MIDDLE SUPERIOR ALVEOLAR

• ANTERIOR SUPERIOR ALVEOLAR

• INFERIOR PALPEBRAL• LATERAL NASAL

• SUPERIOR LABIAL

BRANCHES IN MIDDLE CRANIAL FOSSA

• MIDDLE MENINGEAL NERVE• Travels with middle meningeal artery.• Sensory to the dura matter of anterior half of middle cranial fossa.

TRIGEMINAL NERVE

BRANCHES IN PTERYGOPALATINE FOSSA

A. ZYGOMATIC NERVE: Emerges in the pterygopalatine fossa.

Passes anteriorly and laterally through

inferior orbital fissure into orbit.

DIVIDES INTO 2 PARTS::

1. ZYGOMATICOFACIAL NERVE:

2. ZYGOMATICOTEMPORAL NERVE:

TRIGEMINAL NERVE

B. PTERYGOPALATINE {SPHENOPALATINE} NERVES:

• 2 short nerve trunks that unite at pterygopalatine ganglion.

Most of the fibres pass through the ganglion without synapse.

• BRANCHES: ORBITALNASAL -POSTERIOR SUPERIOR LATERAL NASAL -MEDIAL OR SEPTAL BANCH

PALATINE - GREATER OR ANTERIOR PALATINE

- MIDDLE PALATINE BRANCH

-POSTERIOR PALATINE BRANCH

TRIGEMINAL NERVE

C. POSTERIOR SUPERIOR ALVEOLAR NERVES

• Leave main branch before it enters inferior orbital fissure.• Pass downward over posterior surface of maxilla.• Enter post. superior alveolar canal along with internal maxillary artery.• Supplies-mucous membrane of sinus ,maxillary teeth and its gingivae.

P.S.A

TRIGEMINAL NERVE

BRANCHES IN INFRAORBITAL GROOVE AND CANAL::

1. MIDDLE SUPERIOR ALVEOLAR NERVE

• Leaves in posterior part of floor of

Infraorbital canal.

• Passes downward and anterior over the

anterolateral wall of maxillary sinus.

• Supplies maxillary bicuspids.

2. ANTERIOR SUPERIOR ALVEOLAR NERVE

• Descends from main trunk to emerge in

infraorbital foramen.

• Passes through fine canals in maxilla

• Supplies:

Incisors and cuspids

Anterior Part of maxillary sinus

Labial gingiva of incisors and cuspids

M.S.A

A.S.A

TRIGEMINAL NERVEAs the infraorbital nerve is about to emerge from the foramen in front of maxilla

it divides into:

3 TERMINAL BRANCHES ON FACE

INFERIOR PALPEBRAL BRANCHSupply sensory fibres to skin of

Lower eyelid and its conjunctiva.

LATERAL NASAL BRANCHPass to skin of the side of the nose.

SUPERIOR LABIAL BRANCH

Distributed to the skin & mucous membrane of the upper lip.

INF.

PALP

.

LAT. NAS.

SUP. LAB.

TRIGEMINAL NERVE

MANDIBULAR DIVISION• Largest division of trigeminal nerve.Formed by • SMALL MOTOR ROOT• LARGE SENSORY ROOT

SENSORY ROOT SUPPLIES:• Dura• External ear• Parotid gland• TMJ articulation• Lower teeth and gingiva• Scalp over temporal region• Ant. 2/3rd of the tongue. • skin and mucous membrane of chin, • cheek & lower lip.MOTOR ROOT SUPPLIES:• Muscles of mastication.• Mylohyoid• Anterior belly of digastric

TRIGEMINAL NERVE

COURSE Motor root is located in middle cranial fossa Sensory root emerges from semilunar ganglion 2 roots pass alongside in cranium. Emerging from foramen ovale,they unite.

1. UNDIVIDED NERVE: Nervous spinosus Nerve to internal pterygoid

2. DIVIDED NERVE: Anterior division –Branches to ext. pterygoid, masseter,Temporal, buccal posterior division –Auriculotemporal ,lingual, inferior alveolar

TRIGEMINAL NERVE

BRANCHES FROM UNDIVIDED NERVE:A.) NERVOUS SPINOSUS

Arises outside the skull and then passes in the middle cranial fossa to

supply dura and mastoid cells.

b.) NERVE TO INTERNAL PTERYGOID

A branch passes to innervate internal pterygoid muscle. A sub branch

passes for tensor veli palatini and tensor tympani muscles.

TRIGEMINAL NERVE

BRANCHES FROM DIVIDED NERVE:ANTERIOR DIVISION:A.) PTERYGOID NERVE: Enters the medial side of external pterygoid muscle for its motor supply.

B.) MASSETER NERVE: Passes above the external pterygoid to traverse the mandibular notch and enter the deep side of masseter muscle.

TRIGEMINAL NERVE

C.) TEMPORAL NERVES:Passes upwards crosses the infratemporal crest of sphenoid

bone, enters the anterior deep part of the temporalis muscle.

TRIGEMINAL NERVE

D.) BUCCAL NERVE: Passes downwards, anteriorly and laterally between the two heads

of external pterygoid muscle. At the level of occlusal plane It ramifies-

Motor innervation to cheek

Sensory innervation to cheek

Sensory fibres to retromolar pad

Sensory fibres to buccal gingivae

TRIGEMINAL NERVE

POSTERIOR DIVISIONA. AURICULOTEMPORAL NERVE:

Arises by a medial and a lateral root.

COURSE:

Passes posteriorly,Deep to external

pterygoid muscle.

Between sphenomandibular ligament &

neck of condyle.

Traverses upper deep part of parotid

Crosses posterior root of zygomatic arch

TRIGEMINAL NERVE

• BRANCHES OF AURICULOTEMPORAL NERVE

• PAROTID BRANCHES

• ARTICULAR BRANCHES

• AURICULAR BRANCHES

• MEATAL BRANCHES

• TERMINAL BRANCHES:: Supply scalp over the temporal region.

TRIGEMINAL NERVE

B. LINGUAL NERVE• Passes medially to external pterygoid muscle and descends,

• Lies between internal pterygoid muscle & ramus of mandible in

pterygomandibular space.

• In pterygomandibular space,Lingual

nerve lies parallel to inferior Alveolar

Nerve but lingual & anterior to it.

C. INFERIOR ALVEOLAR NERVE:

Largest branch of the posterior division.

Passes downwards,give branch to

mylohyoid

Enters mandibular foramen,

Distributed throughout mandible.

Reaches mental foramen,

2 terminal branches

• Mental nerve

• Incisive nerve

MYLOHYOID NERVE:

• Branch of inferior alveolar nerve

• Both sensory & motor fibres.

• Continues downward & forward in

mylohyoid groove.

Motor fibres Supply:

• Mylohyoid muscle

• Anterior Belly of digastric

APPLIED ANATOMYTRIGEMINAL NEURALGIA• It is a neuropathic disorder characterized by episodes

of intense pain in the face, originating from the trigeminal nerve

• Tic DoloureauxCLINICAL FEATURES• Pain is unilateral (rarely bilateral).• Duration of pain - few seconds to 1-2 minutes.• Pain may occur several times a day;.• patients typically experience no pain between

episodes.• Trigger zone

• CAUSE1. vascular compression –superior cerebral artery2. multiple sclerosis3. Aneurysm4. tumor 5. arachnoid cyst in the cerebellopontine angle6. by a traumatic event such as a car accident or

even a tongue piercing

Treatment

• Medical

• Surgical

Medical Treatment

• Carbamazepine Should be the initial Rx of choice for classical Trigeminal Neuralgia

If get no or only partial response to carbamazepine, add or substitute another pharmacologic agent: Baclofen : 10 m- 80 mg daily Dilantin Lamictal

Surgical Treatment

• Both percutaneous & open techniques– Glycerol injection Ballon Compression– Radio Rhizotomy Gamma knife– Partial Rhizotomy Microvascular

decompression

ROLE IN PROSTHODONTICS

• Trigger zone • Development of a chronic pain state caused by

injury to peripheral branches of the trigeminal nerve after surgical and nonsurgical procedures.

Delcanho RE Neuropathic implications of prosthodontic treatment.J Prosthet Dent. 1995 Feb;73(2):146-52

ABDUCENT NERVE

ABDUCENT NERVE

• Motor in nature

• Supplies lateral rectus muscle

• Lateral rectus muscle is responsible for visual tracking & fixing of object.

Origin:• Nucleus situated beneath floor of fourth ventricle in dorsal part of pons.

ABDUCENT NERVE

Course • From pons,

• Pierces dura mater

• Inferior petrosal sinus

• cavernous sinus

• Sup.Orbital fissure

• with in tendinous ring supply lateral rectus

ABDUCENT NERVE

APPLIED ANATOMY:

• Involvement produces paralysis of lateral rectus,resulting in medial or

convergent squint or diplopia.

• unable to look laterally

FACIAL NERVE

FACIAL NERVE

• Mixed nerve • Three nuclei -1 motor and 2 sensory• Motor nucleus: it is present in the pons.• sensory –a) the superior salivatory nucleus: b)The nucleus of the tractus solitarius:

COURSE

COURSE Pons

Stylomastoid canal andforamen

Posteromedial surface of Parotid gland

Behind the neck of mandible It divides into its Five terminal branches

BRANCHESA.WITHIN THE FACIAL CANAL-1.Greater petrosal nerve2.Nerve to stapedius 3. Chorda tympaniB.AT ITS EXIT FROM STYLOMASTOID FORAMEN1.Posterior auricular2.Digastric 3.Stylohyoid C.Terminal branches within parotid gland1.Temporal 2.Zygomatic3. Buccal 4.Mandibular5.Cervical

A.WITHIN THE FACIAL CANAL

1.GREATER PETROSAL NERVEsupply mucous glands of nose, palate & lacrimal glands

A.WITHIN THE FACIAL CANAL

2.NERVE TO STAPEDIUS small motor nerve for stapedius muscle whichis attached to the stapesthe innermost of thethree auditory ossciles.

A.WITHIN THE FACIAL CANAL

3. CHORDA TYMPANIThe taste fibers follow thelingual nerve into theSubstance of the tongue & are distributed to the taste buds.

B.AT ITS EXIT FROM STYLOMASTOID FORAMEN

POSTERIOR AURICULAR NERVE Turns backwards & upwards between the mastoid process & the auricle and supplies the posterior auricular & the occipital muscles

C.TERMINAL BRANCHES WITHIN PAROTID GLAND

1.TEMPORAL -the auricular muscles,Frontalis,Orbicularis oculi,Corrugator 2.ZYGOMATIC-Orbicularis oculi3. BUCCAL-Procerus,zygomaticus,Quadratus labii superioris,muscles of the nose,buccinator and orbicularis oris4.MANDIBULAR-muscles of the lower lip and chin5.CERVICAL-Platysma.

APPLIED ANATOMY GENICULATE GANGLION• Ramsay hunt syndrome- Herpes zoster infection of ganglion Signs-• Vesicles on ear, oral mucosa, tonsil, posterior one third of

tongue• Loss of taste• Pain• Decrease salivation• Palatal paralysis

• Definition :- idopathic paralysis of facial nerve of sudden onset.

• Incidence :- 15 – 40 cases per one lac cases.

• Sex predilection :- F > M . It is 3.3 times more common in pregnant women ( especially in third trimester )

• Age :- can occur at any age. More common in middle aged people.

• Side involvement :- equally involved left & right sides. Usually unilateral but in 1% cases bilateral involvement can be seen.

BELL’S PALSY

• Causes:

• Congenital • Trauma • Iatrogenic • Idiopathic • Infection • Toxic • Neurologic • Neoplastic

CLINICAL FEATURES• Facial asymmetry• Drooping of corner of mouth• Inability to close eye• Uncontrolled tearing• Facial muscle atrophy• Eyebrow droop• Loss of forehead and nasolabial folds• Pain near mastoid process• Sensory loss• Others- Hyperacusis,Dysgeusia

• Congenital:- i) Moebius Syndrome :- Due to congenital nuclearaplasia. ii) Melkersson–Rosenthal Syndrome :- Cheilitis Granulomatosa + Facial Palsy + Scrotal Tongue

Neoplastic :-

i) Facial Nerve Tumours – Schwannoma, Neurofibroma

ii) Parotid Tumors

iii) Temporal bone or External Auditory Canal Tumours

Infectious :- i) Mastoiditis

ii) Viral causes :- Herpes zoster (Ramsay Hunt Syndrome ), mumps, infectious mononucleosis

iii) Bacterial causes :- Diphtheria, Tuberculosis

• Eighty percent of patients with Bell's palsy have normal or near-normal recovery without any treatment.

• DRUG THERAPY--CORTICOSTEROIDS-Prednisone 80 mg *5days

-ACYCLOVIR -2000 mg/day*7 days • SURGICAL NERVE GRAFTING ( Hypoglossal nerve has been a very effective

autogenous graft)

TREATMENT

ROLE IN PROSTHODONTICS Complete denture fabrication in patient with bells palsy

• primary and final impressions – excessive material is incorporated on the affected side

• The polished surface of denture base was contoured by functions of the tongue and action and tonus of affected and unaffected lips and cheek

• Occlusal wax Rims - Midline placed in the middle of the oral cavity rather than the facial midline

• Non anatomic posterior teeth are used to establish the centric occlusionSome improvement of the appearance can be achieved by:1. Placing the mesio-incisal point in the middle of the mouth rather than

the middle of the face2. keep the cant of the occlusal plane on the affected side a little low for

incisal show3. Buccal sulcus support - Placing buccal support on the affected side to

reduce the facial droop.This will also help reduce the accumulation of food in the affected buccal vestibule

Suresh S Prosthodontic management of complete edentulous patients with neuromuscular disorders - Case reports. Journal of Advanced Dental Research Vol II : Issue I: January, 2011

VESTIBULOCOCHLEAR NERVE

VESTIBULOCOCHLEAR NERVE

• This nerve is responsible for transmitting sound and equilibrium (balance) information from the inner ear to the brain.

• NUCLEUS -2 cochlear nucleii in inferior cereberal peduncle

-4 vestibular nucleii in pons and medulla

COURSE –• The cochlear nerve travels away from the

cochlea of the inner ear where it starts as the spiral ganglia.Connects organ of corti to cochlear nuclei

• The vestibular nerve travelsfrom the vestibular systemof the inner ear. The vestibular ganglion houses the cell bodies of the bipolar neurons

APPLIED ANATOMY Damage vestibulocochlear nerve may cause the following

symptoms – • hearing loss,• vertigo ,• false sense of motion ,• loss of equilibrium (in dark places) ,• nystagmus ,• motion sickness ,• tinnitus.

GLOSSOPHARYNGEAL

• Mixed nerveMotor fibres – stylopharyngeusSensory fibres – pharynx, tonsils, posterior part of tongue,parotid glandNuclei - medulla

COURSE

COURSE Medulla

Jugular foramen

superior nucleus Inferior nucleus

Parotid gland via lesser petrosal nerve

pharynx,tonsils,tongue

BRANCHES

1.TYMPANIC NERVE2.CAROTID3.PHARYNGEAL4.MUSCULAR5.TONSILLAR6.LINGUAL

APPLIED ANATOMY

1.Tested clinically- • Tickling posterior wall of pharynx• Taste sensibility on posterior one third of tongue2.Isolated lesions- Unknown3.Neuralgia4. Involved in swallowing and gag reflex, considered to be as the taste nerve, mainly for the sweet and bitter tastes.

GLOSSOPHARYNGEAL NEURALGIADEF.-It consists of recurring attacks of severe pain

in back of throat near the tonsils and back of tongue due to malfunction of cranial nerve IX.

Cause-unknown, -artery that compresses the

glossopharyngeal nerve , -tumor in the brain or neck

CLINICAL FEATURES• Attacks are brief• Triggered by chewing,swallowing,coughing or sneezing• Pain begins at back of tongue or back of throat• Pain- unilateral,severe and paroxysmal• Older age group is affected

ROLE IN PROSTHODONTICS GAG REFLEX - Nausea manifests itself through an unpleasant feeling that precedes the sensation of vomiting

Lavinia Ardelean, et al .Gag reflex in dental practice – etiological aspects. TMJ 2003, vol. 53, no. 3-4

PHYSIOLOGICAL MECHANISMS

• Inborn reflex • Regresses in first four years of life. • It becomes more posterior after the appearance

of the first dentition(tonsil pillars)• The persistence - orofacial immaturity in forms

of dysphagia.• The sensor stimuli are detected by three types

of receptors - orofacial, digestive, blood flow level.

OROFACIAL RECEPTORS

• REAL REFLEX FIELD• palatine veil, posterior pharynx ,tonsillar

pillars , receptors,tongue papillae that carry the taste buds are rich in nociceptive

DIGESTIVE RECEPTORS

• The afferences coming from the digestive tract, conveyed mainly through the vagus nerve, reach the solitary nucleus

BLOOD-FLOW RECEPTORS

• Pathological humoral alterations, such as uremia or drug poisoning can act on the bulbar centre of vomiting.

• The hormonal changes inherent to pregnancy act through the blood flow and may induce nausea.

THE IMPORTANCE OF GAG REFLEX ETIOLOGY IN DENTAL PRACTICE

• Clinically, there are several therapeutic actssusceptible to stimulate, directly or indirectly, the areas and reflex paths, a stimulation that is manifested by triggering INBORN OR ACQUIRED, LOCAL OR GENERAL REFLEXES.

INBORN REFLEXES

Any risk of blocking the airways triggers the gag reflex. This depends mainly on two factors:• oral breathing • hypersalivation

ACQUIRED REFLEXES

GENERAL LOCAL ORIGIN

• Alcoholism• Digestive or hepato-biliary disorders• Emetic medication.

• Olfactory/taste stimuli• Mechanical stimuli• Acoustic stimuli• Visual stimuli• Psychic stimuli

MANAGEMENT OF GAG REFLEX

• Distraction techniques• Relaxation• Pharmacological Techniques Local Anesthesia• Conscious sedation

Milind Limaye, Naveen HC, Aditi Samant. The gag reflex etiology and management. International Journal of Prosthetic Dentistry.2010:1(1):10-14. 2010 International Journal of Prosthetic Dentistry

PROSTHODONTIC TECHNIQUES

Borkin recommends low-fusing wax as an impression material Webb suggests that distortion of tissue contour due to injection of anesthetic solution can be minimized by adding hyaluronidase (I-3cc) to 2 % lidocaine HCI (1cc).

MODIFICATION OF EDENTULOUS MAXILLARY CUSTOM TRAY TO PREVENT GAGGING

• The modified maxillary custom acrylic resin tray to which second layer of autopolymerising tray acrylic has been attached to original custom tray with wax spacer removed aids in removal of excess impression material as it extrudes from the posterior border of the maxillary custom tray before it can elicit a gag reflex in the patient.

• PALATE LESS DENTURES: A cast metal denture base of aluminum or chrome nickel alloy is recommended

• THE MARBLE TECHNIQUE• SYSTEMATIC DESENSITIZATION• ERRORLESS LEARNING- The patient is

instructed to set aside time to position the denture closer each day and eventually into the mouth in successive approximations

• Training bases - A thin acrylic denture base, without teeth is fabricated and the patient is asked to wear it at home, gradually increasing the length of time the training base is worn

VAGUS• Mixed nerve• Nuclei-located in medulla

VAGUSCOURSEMedulla

jugular foramen,

carotid sheath

neck, chest and abdomen

viscera

BRANCHES

IN HEAD AND NECK-A.IN JUGULAR FORAMEN-1.Meningeal2.Auricular – skin of ear

B.IN NECK

1.Pharyngeal-muscles and mucous membrane of the pharynx (except the stylopharyngeus) and the muscles of the soft palate, except the Tensor veli palatini

2.Carotid

3.Superior laryngeal

ExternalLaryngeal(cricothyroid)

4.Right recurrent laryngeal –all muscles of larnyx5.Cardiac

Internal laryngeal(mucous membrane of the pharynx and larynx)

APPLIED ANATOMY1.Tested clinically- Comparing palatal arches2.Paralysis- • Nasal regurgitation-pharyngeal branch• Nasal twang in voice - recurrent laryngeal nerve• Hoarseness of voice – recurrent laryngeal nerve• Flattened palatal arch - pharyngeal branch• Dysphagia – pharyngeal branch

ACCESSORY NERVE• Motor nerve• Nucleus – nucleus ambiguus• Formed by spinal and cranial roots

COURSE OF ACCESSORY NERVE

Jugular foramen

Cranial root spinal root

muscle of soft palate and pharynx

sternocleidomastoid and trapezius

APPLIED ANATOMY

• IT IS TESTED CLINICALLY-1.ASKING PT. TO SHRUG HIS SHOULDERS2.TURN FACE TO OPPOSITE SIDE• WRY NECK

HYPOGLOSSAL NERVE

• Motor nerve• Nucleus- hypoglossal nucleus in medulla

COURSE OF NERVEhypoglossal nucleus

hypoglossal canal It spirals behind the vagus nerve and passes between the internal carotid artery and internal jugular vein (carotid sheath)

submandibular region to enter the tongue

BRANCHES1. Meningeal branch2. Descending ramus-

Omohyoideus,Sternohyoideus, the Sternothyreoideus, and the inferior belly of the

Omohyod.3. Thyrohyoid 4. Geniohyoid

APPLIED ANATOMYTested clinically- Protrude tongueLesion of nerve- Paralysis of tongueA.Infranuclear lesions• Gradual atrophy• In motor neuron disease ,syringobulbia

B.Supranuclear lesions• Paralysis without wasting• Seen in pseudobulbar palsy

LYMPHATIC DRAINAGE OF THE HEAD AND

NECK

THE LYMPHATIC SYSTEM

• The lymphatic system is a part of the circulatory system, comprising a network of conduits called lymphatic vessels that carry a clear fluid called lymph unidirectional towards the heart

FUNCTION

• To provide an accessory route for the excess plasma to get returned to the blood.

• Secondly the lymphatic organs play an important part in the immune system

LYMPH

• Lymph is the fluid that circulates throughout the lymphatic system. The lymph is formed when the interstitial fluid is collected through lymph capillaries.It is then transported though lymph vessels to lymph nodes before emptying ultimately into the right or the left subclavian vein, where it mixes back with blood.

FUNCTION OF LYMPH

• Lymph returns protein and excess interstitial fluid to the circulation. Lymph may pick up bacteria and bring them to lymph nodes where they are destroyed. Metastatic cancer cells can also be transported via lymph. Lymph also transports fats from the digestive system

LYMPH NODE

SURFACES

SUBCAPSULAR SINUS

OUTER CORTEX

INNER MEDULLA

• CLASSIFICATION OF HEAD & NECK LYMPH NODES

Classification of Head & Neck Nodes

WALDEYER’S INTERNAL RING • Adenoid• Lingual• Palatine• Posterior pharyngeal wall lymphoid aggregate

WALDEYERS CLASSIFICATION

WALDEYER’S EXTERNAL RING The ring in the head constitues Skull base nodesOccipital nodesPostauricular nodesParotid nodes and Buccal lymph nodes .

The ring in the neck constitutesSuperficial Cervical nodesSubmandibular nodesSubmental and Anterior cervical nodes

SUPERFICIAL LYMPH NODE

• Located at junction of head and neckINCLUDES• occipital• Post auricular• Parotid• Buccal• Superficial cervical• Submental• Submandibular• Anterior cervical

DEEP LYMPH NODE

located along internal jugular vein within carotid sheath INCLUDES• Upper• Middle• LowerIn general lymph flows from superficial to deepand from superior to inferior

SITE SPECIFIC DRAINAGE IN HEAD & NECK

SUPERFICIAL PAROTID LYMPH NODES

• Location-anterior to the tragus superficial or deep to the parotid fascia.

• Drainage

POSTERIOR AURICULAR LYMPH NODES• Location-superficial to the

mastoid attachment of sternocleidomastoid muscle

• Drainage – Strip of Scalp above Auricle Posterior Wall of external

auditary meatus(Upper half of Auricle)

OCCIPITAL NODES

• Location - the superior angle of the posterior triangle superficial to the upper attachment of trapezius

• Drainage - the occipital scalp

SUPERFICIAL CERVICAL LYMPH NODES

• Location - along the external jugular superficial to the sternocleidomastoid muscle.

• Drainage - Floor of the EAM Lobe of the Auricle Skin over Angle of Mandible Lower Parotid region.

SUBMANDIBULAR LYMPH NODES

• Location - internal to the investing layer of the deep fascia of the neck in the submandibular triangle

• Afferents - facial nodes (nasolabial and buccal ) , submental & Parotid nodes may drain

SUBMENTAL LYMPH NODES

• Location - on the mylohyoid muscle between the anterior bellies of digastric.

• Drainage -- Mandibular Anterior Alveolar ridge

Anterior 1/3rd of floor of the mouth

Lower Lip (except lateral thirds)

UPPER DEEP CERVICAL NODES

• Located - upper third of the internal jugular vein deep to the sternocleidomastoid muscle .

• Jugulodigastric node- in triangular region bounded by the posterior belly of digastric , facial vein and IJV.

• Efferents from these nodes drain to the middle deep cervical nodes or directly to the jugular trunk.

Afferents from the parotid posterior-auricular , occipital , superficial cervical , submandibular , retropharyngeal and prelaryngeal lymph nodes

Drains wide areas of face , oral cavity , tongue , tonsils , nose , nasal cavity , nasopharynx , parotid and submandibular gland and supraglottic larynx .

MIDDLE DEEP CERVICAL NODES

Located around middle third of the internal jugular vein

The Juguloomohyoid lymph node lies just on or above the tendon of omohyoid muscle.

Efferents from these nodes drain to the inferior deep cervical nodes or directly to the jugular trunk.

afferents from the upper deep cervical nodes , submental nodes , suprahyoid nodes , prelaryngeal nodes , paratracheal nodes

LOWER DEEP CERVICAL

Location- lower1/3rd of the internal jugular vein

Afferents- middle deep cervical nodes , anterior superficial cervical , spinal accessory nodes and transverse cervical nodes

CLINICAL CONSIDERATIONS

PALPATION OF LYMPH NODES

• Use the pads of all four fingertips

• Examine both sides of the head simultaneously

• Applying steady, gentle pressure

• Evaluated in a systematic fashion

PREAURICULAR NODES

• Stand behind the patient• Gently tilt the head to

the opposite side of node being palpated

• Roll your finger in front of the ear, against the bone.

POSTAURICULAR NODES

• Stand behind the patient

• Gently tilt the head to the opposite side of node being palpated

• Roll your finger behind the auricle , against the mastoid process.

SUBMANDIBULAR NODES

• Stand behind the patient • Gently tilt the head to

the same side of node being palpated

• Roll your fingers against inner surface of mandible applying pressure against the bone.

SUBMENTAL NODES

• Stand behind the patient

• Gently tilt the head in front .

• Roll your fingers against inner surface of symphysis applying pressure against the bone.

SUPERFICIAL CERVICAL NODES

• Stand behind the patient

• Palpate using four fingers above the sternocleidomastoid muscle using rolling motion

DEEP CERVICAL NODES

• They are located deep to the sternocleidomastoid muscle and are often inaccessible

• Palpate by standing behind the patient and hooking thumb and fingers around either side of the muscle.

PATHOLOGIES ASSOCIATED WITH LYMPHATIC SYSTEM

• DEVELOPMENTAL

• NEOPLASTIC

• INFLAMMATORY

CAVERNOUS HEMANGIOMAGIANT CELL LYMPHOMALYMPHOEPITHELIOMALYMPHOENDOTHELIOMALYMPHANGIOSARCOMAUNDIFFRENTIATED LYMPHOMAHODGKINS DISEASENON-HODGKINS DISEASE

CYSTIC HYGROMACONGENITAL LYMPHEDEMA

LymphangitisLymphadenitis LymphoedemaLymphadenopathy

DEVELOPMENTAL PATHOLOGY

• CYSTIC HYGROMA - A cystic hygroma is a congenital multiloculated lymphatic lesion that can arise anywhere, but is classically found in the left posterior triangle of the neck. This is the most common form of lymphangioma

• CONGENITAL LYMPHEDEMA - Congenital lymphedema is a blockage of fluid in the developing fetal lymphatic system.

INFLAMMATORY PATHOLOGIES • LYMPHANGITIS - Lymphangitis is an inflammation of the

lymphatic channels that occurs as a result of infection at a site distal to the channel. The most common cause of lymphangitis in humans is Streptococcus pyogenes

• LYMPHADENITIS is an infection of the lymph nodes. Causes are– Viral -Common upper respiratory infections,Infectious

mononucleosis ,cytomegalo virus,Acquired immunodeficiency syndrome,Rubella,Varicella,Measles

– Bacterial –Septicemia , Typhoid fever, Tuberculosis, Syphilis, Plague

– Protozoal - Toxoplasmosis– Fungal - Coccidioidomycosis

• LYMPHOEDEMA - Lymphedema is a condition characterized by swelling in one or more extremities that results from impaired flow of the lymphatic system. Causes are most commonly filariasis in india, and after breast cancer surgery.

REFERENCES1. N Torbica, S Krstev World at work: Dental laboratory technicians.Occup Environ

Med2006;63:145-1482. Lavinia Ardelean, et al .Gag reflex in dental practice – etiological aspects. TMJ 2003, vol.

53, no. 3-43. Dr. Kalavathi S.D Restoring Ocular Esthetics Using Ocular Prosthesis Journal of Dental

Sciences & Research 1:2: Pages 39-444. Delcanho RE Neuropathic implications of prosthodontic treatment.J Prosthet Dent. 1995

Feb;73(2):146-52 5. Suresh S Prosthodontic management of complete edentulous patients with

neuromuscular disorders - Case reports. Journal of Advanced Dental Research Vol II : Issue I: January, 2011

6. Lavinia Ardelean, et al .Gag reflex in dental practice – etiological aspects. TMJ 2003, vol. 53, no. 3-4

7. Milind Limaye, Naveen HC, Aditi Samant. The gag reflex etiology and management. International Journal of Prosthetic Dentistry.2010:1(1):10-14. 2010 International Journal of Prosthetic Dentistry

8. Grays Anatomy9. Oral Anatomy – Sichers10. B. D. Chaurasia's human anatomy11. Netters Atlas of Human Anatomy12. Clinically Oriented Anatomy – Moore & Dalley13. Development of Human Body– Moore & Persaud14. Medical Physiology- Ganong

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