Trigeminal nerve

1. Introduction
2. List of cranial nerve
3. Embryology of trigeminal nerve
4. Nuclei of trigeminal nerve
5. Trigeminal Ganglion
6. Course of trigeminal nerve
7. Branches
8. Ganglion associated with trigeminal nerve
9. Applied anatomy
10. Conclusion
11. Bibliography

The nervous system of human is made up of innumerable neurons which
further constitute the nerve fibers.
 Nerve :
 Neuron :

Nerve in order
 Cranial Nerve I - Olfactory
 Cranial Nerve II – Optic
 Cranial Nerve III – Occulomotor
 Cranial Nerve IV – Trochlear
 Cranial Nerve V – Trigeminal
 Cranial Nerve VI – Abducens
 Cranial Nerve VII – Facial
 Cranial Nerve VIII – Vestibulocochlear
 Cranial Nerve IX – Glossopharyngeal
 Cranial Nerve X – Vagus
 Cranial Nerve XI – Spinal Accessory
 Cranial Nerve XII - Hypoglossal

 Trigeminal nerve is the largest cranial nerve.
 It is a mixed nerve.
 Composed of a small motor root and a considerably larger sensory root.

Embryology of Nerve
 The pharyngeal arches appear in the fourth and fifth week.
 There are total 6 pharyngeal arches.
 The trigeminal nerve is derived from 1st pharyngeal arch.

 Each arch is characterized by its own:
muscular component
nerve component
arterial component
skeletal component

Nuclei of the trigeminal nerve:
It has got four nuclei:
1. Mesencephalic nuclei
2. Main sensory nuclei-
3. Spinal nuclei
4. Motor nuclei

SENSORY NUCLEI:
1. Mesencephalic nucleus:
 Situated in midbrain.
 Cell body of pseudounipolar neurons.
 Receives general somatic afferent
fibers.
 Relay proprioception from:
- Muscles of mastication
- Facial muscles
- Eye

2. Primary Sensory Nucleus:
 Situated in upper part of Pons lateral to motor nucleus.
 Receives general somatic afferent fibers.
 Relays impulses of touch and pressure from skin and mucous membrane of
facial region.

3. The spinal nucleus
 Extends from caudal end of principal sensory nucleus in Pons to
2nd or 3rd spinal segment where it continues with sub. Gelatinosa
 Divided into three parts:
1. Subnucleus orallis
2. Subnucleus interpolaris
3. Subnucleus caudalis
 It receives general somatic afferent fibers.
 Relays the impulses of pain and temperature of face.

4. The motor nucleus
 It is situated in upper Pons medial to principal sensory nucleus .
 Contains efferent fibers.
 Innervates muscles of mastication and tensor tympani and tensor palatini.

The Trigeminal Ganglion:
 Also known as gasserion ganglion , or semilunar ganglion , is a sensory
ganglion of trigeminal nerve that occupies a cavity( Meckles cave ) in dura
matter ,covering the trigeminal impression near the apex of the petrous
part of temporal bone.
Trigeminal Ganglion

 It is somewhat cresentric or semilunar in shape ,with its convexities
directed anterolateraly .
 The three division of trigeminal nerve emerges from this convexities.

ASSOCIATED ROOTS AND BRANCHES
 The central process of the ganglion from the large sensory root of the
trigeminal nerve, which is attached to Pons at its junction with the middle
cerebellar peduncle.
 The peripheral processes form the three division of the trigeminal nerve.

Relations:
 MEDIALY- Internal carotid artery posterior part of cavernous sinus.
 LATERALY-Middle meningeal artery.
 SUPERIORLY- Parahippocampal Gyrus .
 INFERIORLY-Motor root of trigeminal nerve , greater petrosal nerve, apex
of the petrous temporal bone, foramen lacerum .

ARTERIAL SUPPLY TO THE TRIGEMINAL GANGLION
Ganglionic branches of ICA, middle meningeal artery and accessory
meningeal artery

Branches of The Trigeminal nerve
• Ophthalmic(sensory)
•Maxillary (sensory )
• Mandibular ( Mixed )

The Ophthalmic division:
 Superior and smallest division.
 Completely sensory.
 Arises from the anteriomedial end of trigeminal ganglion as a flat
band,2’5cm long.
 Passes forward in the lateral wall of the cavernous sinus, below the
oculomotor and trochlear nerves

 Nerve is joined by the filaments from the internal carotid sympathetic
plexus.
 It communicates with the oculomotor, trochlear and abducent nerve
through this sympathetic plexus.

Before entering the orbit by the superior orbital fissure it
divides into

Lacrimal nerve
 Smallest of main ophthalmic branches
 Enters the orbit through the lateral part of the superior orbital fissure
 Runs along the upper border of the rectus lateralis with the lacrimal
artery

 Supplies the lacrimal gland and the adjoining conjunctiva. Pierces the
orbital septum.
 Ends in the upper eyelid, where it joins filaments of the facial nerve

Frontal nerve
 Largest branch of the ophthalmic division.
 Enters the orbit by the superior orbital fissure.
 Divides midway between the apex and the base of the orbit into two
branches

Supratrochlear branch
Runs anteromedially ,passing above the trochlear.
Supplies a descending filament to the infratrochlear
branch of nasociliary nerve.
Then it emerges between the trochlear and the
supraorbital foramen and supplies
- Conjunctiva
- - skin of the upper eyelid
- - skin of the lower forehead near the midline

Supraorbital branch
Proceeds between the levator palpabrae superioris
and the orbit al roof
Transverses the supraorbital foramen, supplying
the upper eyelid and conjunctiva
Then ascends on the forehead with the supraorbital
artery , dividing into medial and lateral branches
, which supply the skin of the scalp till the
lambdoid suture
The main nerve and both branches also supply the
mucosa of the frontal sinus and the pericranium .

Nasocilliary Branch
 Intermediate in size between frontal and lacrimaL Deeply placed in the orbit
 Enters the orbit through the annular tendon lying between the two rami of the
oculomotor nerve
 Runs obliquely below the rectus superior to the medial orbital wall
 Here, as anterior ethmoidal nerve, it transverse the anterior ethmoidal foramen
and canals

 Enters the cranial cavity from where it descends into nasal cavity through a slit
lateral to crista galli, supplies two internal nasal branches
 At the lower border of the nasal bone it emerges as the external nasal nerve and
supplies the skin of the nasal ala, apex and vestibule
 The nasociliary nerve connects with the ciliary ganglion and has long ciliary,
intratrochlear and posterior ethmoidal branches

 long ciliary nerve branch from
nasociliary runs forward between
sclera and choroid and supply the
ciliary body, iris, cornea
 The infratrochlear branches from
nasociliary near the anterior
ethmoidal foramen and supplies the
skin of the eyelids and the side of the
nose, conjunctiva, lacrimal sac and
lacrimal caruncle.
 The posterior ethmoidal nerve
leaves the orbit by the posterior
ethmoidal foramen and supplies the
ethmoidal and the sphenoidal
sinuses

The Maxillary Nerve
 It is intermediate division of trigeminal nerve.
 Wholly sensory.
 ORIGIN:
It leaves the trigeminal ganglion between the ophthalmic and mandibular
divisions as a flat plexiform band
Passes slightly medial to lateral wall of cavernous sinus
Leaves the cranium through foraman rotandum , which is located in the greater
wing of sphenoid bone

 Once outside the cranium, it crosses
the uppermost part of the
pterygopalatine fossa, between the
pterygoid plates of sphenoid bone and
the palatine bone
 As it crosses the pterygopalatine fossa
it gives of branches
o Sphenopalatine ganglion
o Zygomatic branches
o Posterior superior alveoar nerve

 It then angles laterally in a groove on the
posterior surface of the maxilla , entering
the orbit through the inferior orbital fissure
 Within the orbit it occupies the infraorbital
groove and becomes the infraorbital nerve ,
which courses anteriorly into the infraorbital
canal
 The maxillary division emerges on the
anterior surface of face through the
infraorbital foramen, where it divides into its
terminal branches, supplying the skin of the
face, nose, lower eyelid and upper lip

Branches of Maxillary nerve
Cranial cavity : Middle Meningeal Nerve
Pterigopalatine Fossa : Zygomatic nerve
Zygomatico temporal
Zygomatico facial
Sphenopalatine Nerve
Posterior Superior Alveolar Nerve
Infraorbital canal : Middle superior alveolar nerve
Anterior superior alveolar nerve
Terminal branches on face: Inferior palpebral branches
Lateral nasal branches
Superior labial branches

Meningeal Nerve:
 Also known as nervus meningeus medius.
 It lies within the cranium.
 It receives a ramus from the internal carotid sympathetic plexus and
accompanies the middle meningeal artery to supply the dura mater

Branches in pterigopalatine fossa
 ZYGOMATIC NERVE : Starts in the pterygopalatine fossa. Enters the
orbit through the inferior orbital fissure. Divides into two branches.
 Zygomaticcotemporal : supplying sensory innervations to skin on
the side of the forehead.
 Zygomaticofacial : supplying the skin on the prominence of the
cheek.

 Before leaving the orbit the zygomatic nerve communicates with the
lacrimal nerve of the ophthalmic division which carries secretory fibers
from pterygopalatine ganglion to lacrimal gland.

POSTERIOR SUPERIOR ALVEOLAR NERVE
 It descends from the main trunk of the
maxillary division in the ptergopalatine
fossa.
 Through the pterygopalatine fossa , it
reaches the inferior temporal surface of the
maxilla.
 From here it enters the alveolar canals on
the infratemporal surface of the maxilla

Travel down the posteriolateral wall of the
maxillary sinus.
Provides sensory innervation to the mucous
membrane of the sinus.
Continuing downward it provides sensory
innervation to the alveoli,periodontal
ligaments , and pulpal tissues of the
maxillary 3rd ,2nd and 1st molar.
Applied anatomy:-During a nerve
block there is great risk of hematoma
formation

Pterigopalatine nerve
 This nerve turns straight downward after it has left the trunk of the second
division. The pterygopalatine ganglion is attached to the medial side of the
nerve

 Branches of pterygopalatine nerve includes those that supply four areas
Orbit
Nose : a) Superior posterior nasal
- Medial
- Lateral
b) Nasopalatine
Palate: Greater Palatine nerve (anterior )
Lesser Palatine nerve (middle & Posterior )
Pharynx
 The orbital branches supply the periosteum of the orbit.

The superior posterior nasal branches are given off at the level of the ganglion.
Enter the nasal cavity through the sphenopalatine foramen.
Lateral branches of superior posterior nasal nerve supply upper and middle
conchae.
Medial branches of the nerve pass over the roof of the nasal cavity to the nasal
septum , one of the medial branches is distinguished by its great length and by its
diagonal course downward and forward along the nasal septum ,it is called the
nasopalatine nerve.

Nasopalatine Nerve
 The nasopalatine nerve gives off branches to
the anterior part of the nasal septum and the
floor of the nose.
 Enters the incisive canal , passes into oral
cavity via the incisive foramen, located in the
midline of the palate about 1cm posterior to
the maxillary central incisors.
 The right and left nasopalatine nerves
emerge together through this foramen and
provide sensation to the palatal mucosa in
the region of premaxilla ( canine to central
incisor
Nasopalatine nerve

GREATER PALATINE NERVE
 Emerges on the hard palate through the greater palatine foramen (usually
located about 1cm towards the palatal midline, just distal to the second
molar) The nerve courses anteriorly supplying sensory innervation to the
palatal soft tissues and bone as far as the first premolar, where it
communicates with the terminal fibers of the nasopalatine nerve. It
provides sensory innervation to some parts of soft palate

 Emerges from the lesser palatine foramen along with the posterior palatine
nerve . Provides sensory innervation to the mucous membrane of soft
palate.
 The posterior palatine nerve: Innervates the tonsillar region.
Middle palatine nerve
The Middle Palatine Nerve

THE PHARYNGEAL BRANCH:
 It is a small nerve .
 Passes through the pharyngeal canal and is distributed to the mucous
membrane of the nasal part of the pharynx .

BRANCHES IN THE INFRAORBITAL CANAL
 The nerve enters the orbit through the inferior orbital fissure, and is then
called the infra orbital nerve passing through the infra orbital canal. Within
the canal it gives of two branches
i.e. Middle superior alveolar nerve and
Anterior superior alveolar nerve

THE MIDDLE SUPERIOR ALVEOLAR NERVE (MSA)
• Arises from the infra orbital nerve.
• Provides sensory innervation to two maxillary premolars and perhaps to
the mesiobuccal root of the first molar and the periodontal tissues, buccal
soft tissues and bone in the premolar region.
• Traditionally it has being stated that the MSA nerve is absent in 30% to
54% of individuals.
• In its absence the usual innervations are provided by either the PSA or the
ASA nerve, most frequently the latter

The Middle Superior and Anterior Superior Alveolar nerve
 Dig.

THE ANTERIOR SUPERIOR ALVEOLAR NERVE (ASA):
 It is a relatively larger branch Given off from the infraorbital nerve at
approximately 6 to 10mm before the latter exit from the infraorbital
foramen
 It provides pulpal innervation to the:
central and lateral incisors
canine., periodontal tissues, buccal bone, mucous membrane of these teeth

BRANCHES ON THE FACE:
 The infraorbital emerges through the infraorbital foramen onto the face to
divide into its terminal branches:
1) the inferior palpebral :- supplying the skin of the lower eyelid
2) the external nasal branch:- providing sensory innervation to skin of lateral
part of the nose
3) the superior labial branch:- supplying the skin and mucous membrane of
the upper lip.

THE MANDIBULAR DIVISION
 Largest division of trigeminal nerve.
 Mixed in nature.
 Has a large sensory root and a small motor
root. The sensory root originates from
trigeminal ganglion whereas the motor root
originates in the Pons and medulla Oblongata .
 The two roots emerge from the cranium
separately through the foramen ovale , the
motor root lying medial to sensory they unite
just outside the skull and form the main trunk
of 3rd division

BRANCHES OF THE MANDDIBULAR NERVE
Branches from main trunk :
Meningeal branch
Nerve to medial pterigoid
Branches from anterior trunk :
Buccal nerve
Branches to muscles of mastication
except medial pterigoid
Branches from posterior trunk :
Auricuotemporal nerve
Lingual nerve
Inferior Alveolar nerve( larger )

Branches of the main trunk
On leaving the foramen ovale the main undivided trunk gives two branches
during its 2-3mm course i.e. the meningeal branch and the nerve to medial
pterygoid
THE MENINGEAL BRANCH
 Also called as Nervus Spinosus.
 It re-enters the cranium through the
foramen spinosum along with the
middle meningeal artery to supply
the duramater.

Nerve to the medial pterigoid
 It is a motor nerve to medial pterygoid muscle
 It supplies one or two filaments which passes through otic ganglion to
supply tensor tympani and tensor veli palatini.

Branches from anterior Division
 Provides motor innervation to the
muscles of mastication sensory
innervation to the mucous membrane of
the cheek and buccal mucous
membrane of the mandibular molars
 The anterior division is smaller than the
posterior division It runs forward under
the lateral pterygoid muscle for a short
distance and then reaches the external
surface of that muscle by passing
between its two heads, from this point
it is known as buccal nerve

Under the lateral pterygoid nerve,it gives off some branches, i.e.
 The deep temporal nerve- to the temporal muscle
 The masseter nerve- providing motor innervation to masseter muscle
 Lateral pterygoid nerve- providing motor innervation to the lateral
pterygoid muscle

Buccal Nerve
Also known as long buccal nerve
Usually passes between the two heads of
the lateral pterygoid
Reaches the external surface of the
muscle follows the inferior part of the
temporal
muscle emerges under the anterior border
of the masseter muscle
At the level of occlusal plane of the
mandibular 3rd and 2nd molar

Crosses in front of the ramus
Enters the cheek through buccinator muscle
 Provides sensory innervation to:
- skin over the anterior part of buccinator
- buccal gingiva of mandibular molars
- mucobuccal fold in that region
 The bucaal nerve does not innervate the
buccinator muscle,the facial nerve does

Branches of Posterior Division
 Larger division Mainly sensory
Auriculotemporal Nerve
It has two roots :
encircles the middle meningeal artery
runs back under lateral pterygoid on
the surface of tensor veli palatine to
pass between the sphenomandibular
ligament and the neck of the
mandible

then lateraly behind the the
temporomandibular joint in relation
with the upper part of the parotid gland
emerging from behind the joint it ascends
posterior to the superficial temporal
vessels over posterior root of the
zygoma
divides into superficial temporal
branches.

 BRANCHES OF AURICULOTEMPORAL NERVE:
anterior auricular branch.
external acoustic meatus.

 The articular branch- supplying the temporomandibular joint
 Superficial temporal branch- supply skin in the temporal region and
connects with the facial and zygomaticotemporal nerves.
COMMUNICATIONS
It communicates with facial nerve providing sensory fibers to the skin over
the areas of innervation of motor branches of facial nerve
It communicates with the otic ganglion providing sensory,secretory and
vasomotor fibers to parotid gland.

THE LINGUAL NERVE:
Second branch of the posterior division
of mandibular nerve
Runs between the tensor veli palatini
and lateral pterygoid,where it is joined
by chorda tympani branch of facial
nerve from here
It decends to rest between the ramus
and medial pterygoid muscle in the
pterygomandibular space

It runs anterior and medial to the inferior
alveolar nerve whose path is parallel to
it.
It then continues to reach the side of the
base of the tongue slightly below and
behind the mandibular 3rd molar.
Here it lies just below the mucous
membrane in the lateral lingual sulcus

It then proceeds anteriorly across the
muscles of the tongue
Looping medial to submandibular
duct (Wharton's duct) to deep
surface of submandibular and
sublingual gland where it breaks up
into terminal branches

SUPPLY OF LINGUAL NERVE
 Supplies the mucosa of the floor of the mouth, lingual gingivae.
 Mucosa of anterior two third of the tongue.
 Also carries postganglionic fibers from submandibular ganglion to
sublingual and anterior lingual glands
APPLIED ANATOMY
Lingual nerve is at great risk during surgical removal of impacted third
molar.
During removal of submandibular salivary gland.

INFERIOR ALVEOLAR NERVE
 Largest branch of the mandibular division
Descends medial to the lateral pterygoid
muscle and lateroposterior to lingual nerve.
Passes between the sphenomandibular
ligament and the mandibular ramus to enter
the mandibular canal via mandibular
foramen.
Through out its path it is accompanied by
inferior alveolar artery and inferior alveolar
vein.
Nerve travels anteriorly in the canal till it
reaches the mental foramen.

Inferior Alveolar Nerve
Mental Nerve Incisive Nerve

 THE INCISIVE NERVE
Continues forward in the bony canal giving off branches to:
canine
incisors
associated labial gingiva
THE MENTAL NERVE
Exists the canal through the mental foramen between and just below the
apices of the premolar, and divides into three branches that innervates:
skin of the chin
skin of the lower lip
buccal mucosa from second
premolar to the midline.

THE MYLOHYOID NERVE
 Just before entering the mandibular
canal, the inferior alveolar nerve gives off a
small mylohyoid branch
 It pierces the sphenomandibular ligament
and enters a shallow groove on medial
surface of mandible
 Follows a course roughly parallel to inferior
alveolar nerve passes below the origin of
mylohyoid muscle lies superficial to the
surface of mylohyoid muscle
 It is a mixed nerve
Provides motor innervation to:
- mylohyoid and anterior belly of digastric
- sensory fibers to inferior and anterior
surfaces mental protuberance
mandibular incisors (sometimes)

GANGLIA ASSO WITH THE TRIGEMINAL NERVE
 1.CILLIARY GANGLION
- connected with nasocilliary nerve by ganglionic branches in orbit,
- non synapsing sensory for orbit

2.PTERYGOPALATINE GANGLION:
- connected to maxillary nerve in infratemporal fossa
- sensory to orbital septum, orbicularis and nasal cavity, maxillary sinus ,
palate , nasopharynx

3. OTIC GANGLION:
- lies between trunk of mandibular nerve and tensor palatini , nerve to med
pterygoid passes through but does not synapse in the ganglion.

4.SUBMANDIBULAR GANGLION:
- related to lingual nerve , rest on hyoglossus supplies post ganglionic
Parasympathetic secretomotor fibers to submandibular and sublingual
gland

APPLIED ANATOMY
 1.Trigeminal neuralgia.
 2. Herpes zoster ophthalmicus.
 3.Wallenberg Syndrome.
 4. Nerve blocks of maxillary and mandibular region

 Trigeminal Neuralgia :
- also known as Fothergill’s disease, Tic douloureux (painful jerking)
- it is defined as , sudden ,usually ,unilateral ,severe ,brief ,stabbing ,
lancinating , recurring pain in the distribution of one or more branches of
trigeminal nerve.
- Mean age: 50 y onwards
- Female predominance (male : female = 1:2 ~2:3

 Pathogenesis of trigeminal neuralgia
It is usually idiopathic.
The probable etiologic factors are:
Intra cranial tumors:-Traumatic compression of the trigeminal nerve by
neoplastic (cerebellopontine angle tumor) or vascular anomalies e.g.
arteriovenous malformations.
Infections :- granulomatous and non granulomatous infections involving
5th cranial nerve

 postherpetic neuralgia
 Demyelinating conditions
 Multiple sclerosis (MS)
 Petrous ridge compression
 Intracranial vascular abnormalities

 General characteristics
Incidence:- seen in about 4 in 100000 persons ,Age of occurrence:- 5th to
6th decade
Sex predilection:-female predisposition
Side involved more frequently:-right side
Division of trigeminal nerve involve; most commonly mandibular >
maxillary >ophthalmic

 Clinical characteristics:
- sudden, unilateral ,intermittent, paroxysmal ,sharp shooting ,lancinating,
shock like pain elicited by slight touching.
- superficial trigger points which radiates across the distribution of one or
more branches of the trigeminal nerve.
- pain rarely crosses the midline, pain is of short duration and last for few
seconds to minutes.
- in extreme cases patient has a motionless face called the frozen or mask
like face.
- presence of intraoral or extra oral trigger points

Provocated by obvious stimuli like
 Touching face at particular site
 Chewing
 Speaking
 Brushing
 Shaving
 Washing the face
The characteristic of the disorder being that the attacks do not occur during
sleep.

DIAGNOSIS:
 CLINICAL EXAMINATION with HISTORY is mandatory .Response to
treatment with tablet of carbamazepine is universal .
 Injections of local anesthetic agents into patients trigger zone gives
temporarily relief from pain.

TREATMENT:
 Medical treatment
 Surgical treatment:
 Peripheral injections
 Peripheral neurectomy
 Cryotherapy
 Peripheral radiofrequency
 Neurolysis (thermocoagulation)
 Gasserian ganglion procedures

MEDICINAL TREATMENT:
 Carbamazapine and phenytoin are the traditional anticonvulsants given
primarilary.
 The dosage of the drug used initially should be kept small to minimum
especially in elderly patients to avoid nausea, vomiting and gastric
irritation.
 Dosage should be taken at night so that adequate serum concentration is
present early morning.

Side effect:
 Visual blurring
 Dizziness
 Rashes
 Hepatic dysfunction
 Leucopenia
 Thrombocytopenia

 Once the pain remission has being achieved the drug dose should be kept
at maintenance level or withdrawn and restarted if symptoms reappear.
 When carbamazepine is contraindicated clonazepam can be given .
 Co-administration of phenytion or baclofen is also advocated.

 THE ALCOHOLIC INJECTIONS:
95% ABSOLUTE alcohol in small quantities 0.5 to 2 ml is given in peripheral
branches of trigeminal nerve.
Side effect:
Repeated injections may cause
 Local tissue toxicity
 Inflammation
 Fibrosis
 Burning alcohol neuritis

Peripheral neurectomy (nerve avulsion):
 Oldest and the most effective procedure, Simple
 Relatively reliable
 Indicated in patients in whom craniotomy is contraindicated due to
age,debility,limited life expectancy
 Acts by interrupting the flow of a significant number of afferent impulses
to central trigeminal apparatus.
 Performed mostly on infraorbital, inferior alveolar, mental and rarely
lingual nerve.

CRYOTHERAPY FOR PERIPHERAL NERVE:
 Direct application of cryotherapy probe (nitrous oxide probe)
 Temperature colder than -60 degree C,for 2-3 minutes Repeated three
times .
 Produces WALLERIAN degeneration without destroying the nerve sheath

PERIPHERAL RADIOFREQUENCY NEUROLYSIS
THERMOCOAGULATION:
 Radiofrequency electrode that has the capacity to destroy the pain fibers is
used in this procedure.
 Temperature being 65 to 75 degree C for 1 to 2 minutes.
 Shown to induce pain remissions in 20%of cases.

GASSERIAN GANGLION PROCEDURS:
Includes various procedures:
1.Gycerol injection
2.Thermocoagulation
3.Ballon compression

GYCEROL INJECTIONS
 Absolute alcohol or phenol-glycerol mixture can be used as the neurolytic
agents.
 Agent is injected into meckel’s cave or in the ganglion.
 Causes damage to nerve cells presumably through dehydration.
 It induces pain relief in 80% of the cases.

THERMOCOAGULATION:
 A radiofrequency electrode that has the capacity to destroy pain fibers is
used.
 Alternating currents of high frequency is passed through the electrode.
 It produces ionization in the biological tissues leads to coagulation of
tissues

BALLON COMPRESSION:
 A Fogarty catheter 1 to 2cm is advanced within the meckels cave through
foramen ovale.
 Inflated up to 0.75ml at the ventral aspect of the ganglion root for 1
minute.
 It destroys the root fibers

HERPES ZOSTER OPHTHALMICUS:
 Caused by Varicella zoster
 Predilection for nasociliary branch of ophthalmic division of the trigeminal
nerve
CLINICAL FEATURES:
Cutaneous lesions:
Rash
Vesicle
Pustule crust permanent scar

Ocular lesions:
 Eyelid:- Periorbital pain
- Edema
- Hyperesthesia
- Conjunctivitis
- Scleritis
- Corneal scarring
- Glaucoma

TREATMENT:
 Acyclovir 800mg 5 times /day within 4 days of onset of rash
 Analgesics
 Antibiotic ointments
 Systemic steroids 60mg/day
 Corneal grafting

Wallenberg syndrome
which causes loss of pain/temperature sensation from one side of the face
and the other side of the body.
ETIOLOGY:
In the medulla, the Ascending Spinothalamic Tract (which carries
pain/temperature information from the opposite side of the body) is
adjacent to the Descending Spinal Tract of the fifth nerve (which carries
pain/temperature information from the same side )

 A stroke cuts off the blood supply to this area .
 Destroys both tracts simultaneously.
 Results in loss of pain/temperature sensation in a unique “checkerboard”
pattern (ipsilateral face, contra lateral body) Characteristic diagnostic
feature

Maxillary nerve blocks:-
 Infra orbital nerve block .
 Posterior superior nerve block .
 Nasopalatine nerve block
 Greater palatine nerve block

Infra orbital nerve block:
Area anaesthetized:
• Incisors
• Cuspids
• Premolar
• Mesiobuccal root of the first molar
• Bony support
• Soft tissue
• Upper lip
• Lower eyelid
• Portion of nose on same side

ANATOMICAL LANDMARKS:
 Infra orbital ridge
 Infra orbital depression
 Supra orbital notch
 Infra orbital notch
 Anterior teeth
 Pupils of the eye

Posterior Superior Nerve Block:
Area anesthetized:
 maxillary molars with the exception of mesiobuccal root of 1st molar
buccal alveolar process of maxillary molars periosteum connective tissue
mucous membrane

 Anatomical Landmarks:
• Muccobuccal fold and its concavity
• Zygomatic process of maxilla
• Infratemporal surface of maxilla
• Anterior border and coronoid process of ramus of mandible
• Tuberosity of maxilla
Complication: pterygoid plexus puncture maxillary artery perforation

 Nasopalatine nerve block:
Area anesthetized: Anterior portion of hard palate i.e canine to canine

Anatomical landmarks: Central incisor Incisive papilla in the midline of the
palate

Greater Palatine nerve block:
Area anesthetized:
Posterior portion of the hard palate and overlying structures up to 1st
premolar area on the side injected.

Anatomical Landmarks:-
 2ND and 3rd molar -palatal gingival margin of 2nd and 3rd molar midline of
palate-a line appox. 1cm from the palatal gingival margin towards the
midline of palate.

Mandibular nerve blocks:
 a)Inferior alveolar nerve block
 b)Incisive nerve block
 c)Mental nerve block
 d)Long Buccal nerve block

 Inferior alveolar nerve block:
Area anesthetized:
Body of the mandible inferior portion of the ramus of the mandible.
Mandibular teeth. Mucous membrane and the underlying tissues that are
anterior to the 1st molar tooth

Anatomical landmarks :
 Mucobuccal fold
 Anterior border of the ramus of the mandible
 External oblique ridge
 Retromolar triangle
 Internal oblique ridge
 Pterygomandibular ligament
 Buccal sucking pad
 Pterygomandibular space

Anatomical landmarks in children

 Symptoms of Anesthesia
1. Subjective symptoms – Tingling and numbness of lower lip and when
the lingual nerve is affected, the tip of the tongue.
2. Objective symptoms – Instrumentation necessary to demonstrate
absence of pain sensation.
Complication -facial nerve paralysis -pain due to contact with the bone too
forcefully

Mental nerve block:
Area anesthetized:-
Buccal mucous membrane anterior to the mental foramen i.e. the 2nd
premolar region to midline -skin of lower lip.

 Landmark:-
- mandibular premolar
- mucobuccal fold at or just anterior to the mental foramen (usually located
between the apices of 1st and 2nd premolars
Complication:-
hematoma formation

Incisive nerve block:
Area anesthetized:-
mental+incisive
i.e. buccal mucous membrane anterior to the mental foramen i.e. the 2nd
premolar region to midline skin of lower lip. -pulpal nerve fibers to
premolar, canine and incisors.

Indication:
When dental procedures have to be carried out in anterior region.
- infection
- acute inflammation
Landmark:
same as mental nerve block, except needle should penetrate into the
mental foramen.

 Long Buccal nerve block:
Area anesthetized:
buccal mucous membrane and mucoperiosteum mandibular molar
region

 Landmarks:
-external oblique ridge
-retromolar triangle
Indication: -surgery in mandibular buccal mucosa supplement inferior
alveolar nerve block

 Conclusion:
Trigeminal nerve, its anatomic course and branches are very important
from a dentist point of view as in advertant surgical procedure may lead to
trigeminal nerve injury. Disorders of Trigeminal nerve are not rare ,knowing
about it will help in formulating appropriate diagnosis and treatment thus
achieving the best possible recovery of Trigeminal nerve function. Nerve
blocks given for carrying various dental procedures involves the various
branches of Trigeminal nerve , hence to avoid any complications ,one
needs to have a knowledge about the course and branches of the nerve .

 BIBLIOGRAPHY
 Anatomy of Head and Neck (B D Chaurasia )
 Grays Anatomy
 Anatomy for Dental students ( Inderbir Singh )
 Handbook of local anesthesia ( Stanley Malamed )
 Textbook of Oral and Maxillofacial Surgery ( Neelima Malik )
 Craniofacial Embryogenetics & Development (Geoffrey H. Sperber )

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