• The nervous system of man is made up of innumerable neurons
which further constitute the nerve fibres
• Nerve :
A bundle of fibers that uses chemical and electrical signals to
transmit sensory and motor information from one body part of
the body to another.
• Neurons :
These are specialized cells that constitute the functional units of
the nervous system and has a special property of being able to
conduct impulses rapidly from onepart of the body to another.
• The cranial nerves are composed of twelve pairs of nerves
that originate from the nervous tissue of the brain.
• In order to reach their targets they must ultimately
exit/enter the cranium through openings in the skull.
• Hence, their name is derived from their association with
Nerve in order
1. Cranial Nerve I - Olfactory
2. Cranial Nerve II - Optic
3. Cranial Nerve III - Occulomotor
4. Cranial Nerve IV - Trochlear
5. Cranial Nerve V - Trigeminal
6. Cranial Nerve VI - Abducens
7. Cranial Nerve VII - Facial
8. Cranial Nerve VIII- Vestibulocochlear
9. Cranial Nerve IX - Glossopharyngeal
10.Cranial Nerve X - Vagus
11.Cranial Nerve XI - Spinal Accessory
12.Cranial Nerve XII - Hypoglossal
• The trigeminal nerve is so called because of its three main divisions i.e.
the Ophthalmic, Maxillary & Mandibular nerves.
• It is the largest of the cranial nerves.
• It is the fifth cranial nerve
• It is a mixed nerve : Sensory and Motor
• It is sensory to the greater part of the scalp, the teeth, and the oral and
• Motor supply is to the MOM. Proprioceptive nerve fibres arise from
the masticatory and extra-ocular muscles.
• A cranial nerve nucleus is a collection of neurons (gray
matter) in the brain stem that is associated with one or
more cranial nerves.
• Axons carrying information to and from the cranial nerves
form a synapse first at these nuclei.
• Lesions occurring at these nuclei can lead to effects
resembling those seen by the severing of nerve(s) they are
SENSORY NUCLEI :
1.Mesencephalic nucleus :
• Cell body of Pseudounipolar neuron
• Relay proprioception from muscles of mastication, Extra
ocular Muscles, Facial muscles.
• Situated in Midbrain just latetral to Aqueduct.
COURSE & DISTRIBUTION
• Both motor and sensory root are attached ventrally to
junction of pons and middle cerebellar peduncle with
motor root lying ventromedially to the sensory root.
• Pass anteriorly in middle cranial fossa to lie below
tentorium cerebelli in cavum trigeminale, here motor root
lies inferior to sensory root.
• Sensory root connected to postromedial concave border of
the trigeminal ganglion.
• Convex antrolatateral margin of the ganglion gives
attachment to the 3 div. of the trigeminal nerve.
• Motor root turns further inferior with sensory component
of V3 to emerge out of foramen Ovale as Mandibular nerve.
• Ophthalmic and Maxillary division emerges through
Superior orbital fissure and foramen Rotundum
THE TRIGEMINAL GANGLION
• SEMILUNAR OR GASSERIAN GANGLION.
• Cresentric in shape with convexity anterolaterally.
• Contains cell bodies of pseudounipolar neurons.
• LOCATION: lies in a bony fossa at apex of the petrous
temporal bone on floor of middle cranial fossa, just
lateral to posterior part of lateral wall of the cavernous
• COVERINGS: covered by dural pouch = MECKLES
CAVE or CAVUM TRIGEMINALE cave lined by pia and
arachnoid thus the ganglion is bathed in CSF.
• ARTERIAL SUPPLY: Ganglionic branches of Internal
Carotid Artery, middle meningeal artery and accessory
• SUPERIORLY: *superior petrosal sinus
*free margin of tentorium cerebelli
• INFERIORLY: *motor root
*greater petrosal nerve
• MEDIALLY: *posterior part of lateral wall of cavernous
*Internal Carotid Artery with its sympathetic
• LATERALLY: *uncus of temporal lobe
*middle meningeal artery and vein
• It is the superior division of the V nerve & is the
• Leaves the cranium and enters the orbit through
superior orbital fissure.
• It is wholly sensory.
• It has 3 branches. All 3 of them pass through the sup.
Orbital fissure into the orbit.
• They are;
1. Lacrimal nerve:
• It is the smallest.
• It supplies the lacrimal gland & the conjuntiva. It pireces the
orbital septum and ends in the skin of the upper eyelid.
2) Frontal nerve:
• It is the largest branch & appears to be the direct continuation
of the ophthalmic division.
• It enters the orbit through the SOF divides into 2 branches.
i. The supra orbital branch: It is larger & more laterally placed.
It supplies the skin of the forehead &
scalp as far back as the vertex.
It also supplies the mucous membrane
of the frontal sinus & pericranium
ii. The supra trochlear branch: It is smaller & more medially
placed. It curves upward on the
forehead , close to the bone.
It supplies the skin of the upper
eyelid & lower part of theforehead.
3) Nasocilliary nerve:
• It is intermediate in size & runs more deeply. Its branches
are divided as following;
i. Branches in the Orbit
ii. Branches in the Nasal cavity
iii. Branches on the face
(I) Branches in the Orbit:
i. Long root of the cilliary ganglion: It is sensory &
passes through the ganglion without synapsing and
supplies the eyeball.
ii. Long ciliary nerve: Supplies the Iris & Cornea.
iii. Posterior ethmoidal nerve: It enters the post
ethmoidal canal & supplies to the mucous membrane
lining of the Post. Etmoidal & Sphenoidal paranasal air
iv. Anterior ethmoidal nerve: It supplies to the Ant.ethmoidal
& frontal paranasal air cells. In the upper part of the nasal
cavity, it further divides into:
1) Internal nasal branches: It has medialseptal branches to
the septal membrane. It also has lateral branches, which
supply the nasal conchae & the ant. nasal wall
2) External nasal branches: supplies the skin on the tip & ala
of the nose.
2) Branches in the nasal cavity:
The branches arising here supply the mucous membrane of
the nasal cavity.
3) Terminal branches on the face:
They supply sensory nerves to the skin of the medial parts
of the both eyelids, the lacrimal sac. They also supply skin on
the bridge of the nose.
• This is the second & intermediate division of the trigeminal
• It is wholly sensory.
• Course: It begins at the middle of the trigeminal ganglion as a
flattened, plexiform band, passes horizontally forwards along
the lateral wall of the cavernous sinus. It leaves the skull
through the foramen rotundum & becomes more cylindrical &
firmer in texture.It crosses the upper part of the pterygopalatine
fossa, inclines laterally on the posterior part of the orbital
process of the maxilla & enters the orbit through the inferior
orbital fissure.It is now termed as the infra orbital nerve. It passes
through the infra orbital groove & canal in the floor of the orbit
& appears on the face through the infra orbital foramen.
• The branches of the maxillary nerve can be divided into
the following 4 groups:
1) In the cranium: Meningeal
2) In the pterygopalatine fossa: Ganglionic, Zygomatic,
3) In the infra orbital canal: Middle sup. alveolar,
Anterior superior/ Greater alveolar
4) On the face: Palpebral, nasal, superior labial
I. Branch given off on the cranium
1. Meningeal branch: It is given off near the foramen
rotundum. It supplies the duramater of the anterior &
middle cranial fossae.
II. Branches in the pterygopalatine fossa.
1. The ganglionic branches: They connect the maxillary
nerve to the pterygopalatine ganglion.They contain secretomotor
fibres to the lacrimal gland. They provide sensory fibres to the
orbital periosteum & mucous membrane of the nose, palate &
2. The zygomatic nerve: It arises in the pterygopalatine
fosssa from the maxillary nerve and travels anteriorly ,
entering through the inferior orbital fissure where it divides into 2
branches. The Zygomaticofacial nerve perforates the facial
surfaces & supplies the skin over the zygomatic bone..
• The Zygomaticotemporal nerve perforates the temporal surface of
the zygomatic bone , pierces the temporalis fascia, & supplies the
skin over the anterior temporal fossa region.
3. Posterior superior alveolar nerve:
• It begins in the pterygopalatine fossa but divides into 3 branches
which emerge through the pterygomaxillary fissure.
• 2 branches enter the posterior wall of the maxilla above the
tuberosity & supply the 3 molar teeth(except the mesiobuccal root
of first molar).
• The third branch pierces the buccinator & supplies the adjoining
part of the gingiva & cheek along the buccal side of the upper
The branches of the Pterygopalatine ganglion are:
I. Orbital branches: periosteum of the orbit.Posterior ethmoidal &
sphenoidal air cells.
II. Palatine branches:
1.Anterior/greater palatine : mucosa of the hard palate & palatal gingiva.
2.Middle palatine : mucous membrane of the soft palate
3.Posterior palatine : mucous membrane of the Tonsillar area.
III. Nasal branches:
1.Posterior superior lateral : posterior part of the nasal conchae
2.Nasopalatine/Sphenopalatine : mucous membrane of the premaxilla.
IV. Pharyngeal branch: mucous membrane of the nasopharynx
III. Branches in the Infraorbital canal
( Infraorbital nerve)
1. Middle superior alveolar nerve:
• It arises from the Infra orbital nerve & runs downwards & forwards
along the infraorbital groove along the lateral wall of the maxillary
• It divides into branches which supply the maxillary premolars &
mesiobuccal root of the first molar teeth.
2. Anterior superior alveolar nerve:
• It also arises in the infraorbital canal near the mid point. It runs in the
anterior wall of the maxillary antrum. It runs inferiorly & divides into
the branches, which supply the canine & incisors.
• A nasal branch from this nerve, given off from the superior dental
plexus supplies the mucous membrane of the anterior part of the lateral
wall & floor of the nasal cavity. It ends in the nasal septum.
• IV. Branches given on the face:
1. The palpebral branches:
• They arise deep to the orbicularis oculi & pierce the muscle, supplying
the skin over the lower eyelid& lateral angle of the eye along with the
Zygomaticofacial & Facial nerves.
2. The nasal branches:
• They supply the skin of the nose & tip of the nasal septum & join the
External nasal branch of the anterior ethmoidal nerve.
3. The superior labial branches:
• These are large & numerous. They supply the skin over the anterior
part of the cheek & upper lip including the mucous membrane & labial
glands. They are joined by the facial nerve & form the infraorbital
• It is the third & largest division of the trigeminal nerve.
• It is made up of 2 roots: a large sensory root which proceeds
from the lateral part of the trigeminal ganglion & almost
immediately emerges out through the foramen ovale & a small
motor root which passes below the ganglion, & unites with the
sensory root just outside the foramen.
• Immediately beyond the junction of the 2 roots, the nerve sends
off the meningeal branch & the nerve to the medial pterygoid.
Now the main trunk divides into a small anterior & a large
• As it descends from the foramen, the mandibular nerve lies at a
distance of 4 cm from the surface & a little in front of the neck
of the mandible.
The braches of the Mandibular nerve:
I. Branches of the undivided nerve.
i. Meningeal branch/nervus spinosus.
ii. Nerve to the medial pterygoid
II. Branches of the divided nerve:
(A) Anterior division: (B) Posterior division:
1.Buccal nerve 1. Auriculotemporal nerve
2.Massetric nerve 2.Lingual nerve
3.Deep temporal nerve 3.Inferior alveolar nerve
4.Nerve to the lateral pterygoid
BRANCHES OF THE UNDIVIDED NERVE
• It enters the skull through the foramen spinosum along
• It has anterior & posterior divisions that supply the dura
of the middle & anterior cranial fossae.
2. Nerve to the medial pterygoid:
• It is a slender branch that supplies to the deep surface of
• It also gives 1-2 filaments to the tensor tympani & the
tensor veli palati muscles.
• BRANCHES OF THE DIVIDED NERVE
I. Anterior division
1.The buccal nerve:
• It passes between the 2 heads of the lateral pterygoid &
descends beneath or through the temporalis. It emerges
from under cover of the ramus & ant. border of the
masseter & unites with the buccal branches of he facial
• It supplies the skin over the ant. part of the buccinator &
mucous membrane lining the buccal surface of the gum.
2.The massetric nerve:
• Passes laterally above the lateral pterygoid in front of the TMJ &
behind the tendon of temporalis.
• It passes through the mandibular notch to sink into the masseter
• It also gives a branch to the TMJ.
3.The deep temporal nerves:
• They are 2 in number.
• They pass above the upper head of the lateral pterygoid, turn above
the infra temporal crest & sink into the deep part of the temporalis
4.The nerve to the lateral pterygoid
• These are 2 in number; one supplying each muscle head.
1.The Auriculotemporal nerve:
Course of the nerve
• The auriculotemporal nerve arises by a medial & lateral roots,
that enclircle the MMA & unite behind it just below the
• The united nerve passes backwards, deep to the lateral
pterygoid muscle & passes between the sphenomandibular
ligament & the neck of the condyle.
• It then passes laterally behind the TMJ i.r.t. to the upper part of
the parotid. It emerges from behind the TMJ, ascends posterior
to the superficial temporal vessels & crosses the posterior root of
the zygomatic arch.
Branches of the Auriculotemporal nerve:
1. Parotid branches: secretomotor, vasomotor.
2. Articular branches: to the TMJ.
3. Auricular branches: to the skin of the helix & tragus.
4. Meatal branches: Meatus of the tymphanic
5. Terminal branches: Scalp over the temporal region
• It lies between the ramus of the mandible & the muscle in the
• It then passes deep to reach the side of the tongue. Here it lies in
the lateral lingual sulcus against the deep surface of the
mandible on the medial side of the roots of the third molar tooth
where it is covered only by mucous membrane of the gum.
• From here it passes on to the side of tongue where it is crosses
the styloglossus & runs on the lateral surface of the hyoglossus
& deep to the mylohyoid in close relation to the deep part of the
submandibular gland &its duct.
• It gives off sensory fibres to the tonsil & the mucous membrane
of the posterior part of the oral cavity.
Branches of lingual nerve and its communications:
2.Communications with submandibular ganglion
Inferior alveolar nerve
• It is the largest terminal branch of the posterior division of the
• The nerve descends deep to the lateral pterygoid muscle at the
lower border of the muscle, it passes b/n the sphenomandibular
ligament & the ramus to enter the mandibular foramen.
• In the canal the nerve runs alongside the inferior alveolar artery
as far as the mental foramen where it emerges out& gives off the
mental & incisive branches.
• From here the nerve runs in the canal giving of branches to the
mandibular teeth as apical fibres & enters the apical foramina
of the teeth to supply mainly the pulp as well as the
Branches of the nerve :
1. Mental nerve: it supplies to the skin of the chin & the
mucous membrane as well as the skin of the lower lip.
2. Incisive branch: continues anteriorly from the mental
nerve in the body of the mandible to form the incisive
plexus & supplies the canine & incisors.
3. Mylohyoid nerve: it is given of before the nerve enters
the canal & contains both sensory & motor fibres.It
pierces the sphenomandibular ligament, descends in a
groove in the medial side of the ramus & passes beneath
the mylohyoid line supplying the mylohyoid muscle as
well as the anterior belly of the digastric.
Ganglia Associated With The
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, max sinus, palate, nasopharynx.
3. Otic Ganglion: betwn trunk of mandibular n and tensor palatini,
nerve to med pterygoid passes thru but does not synapse in the
4.Submandibular Ganglion: related to lingual n, rests on
hypoglossus supplies post gang. Parasym secretomotor fibres to
submandibular and sublingual gland.
• Also known as Fothergill’s disease,Tic douloureux
• It is defined as , sudden ,usually ,unilateral ,severe
,brief ,stabbing , lancinating , recurring pain in the
distribution of one or more branches of trigeminal
• Mean age: 50 y onwards
• Female predominance (male : female = 1:2 ~2:3)
Pathogenesis of trigeminal neuralgia:
• It is usualy idiopathic.
• The probable etiologic factors are:
Intra cranial tumors: Traumatic compression of the
trigeminal nerve by neoplastic (cerebellopontine
angle tumor) or vascular anomalies eg arteriovenous
: granulomatous and non granulomatous infections
involving 5th cranial nerve.
• Pulsation of vessels upon the
trigeminal nerve root do not
visibly damage the nerve.
• However, irritation from
repeated pulsations may lead
to changes of nerve function,
and delivery of abnormal
signals to the trigeminal
• Over time, this is thought to
cause hyperactivity of the
trigeminal nerve nucleus,
resulting in the generation of
• 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 involved; most
commonly : max> mand> oph
• superficial trigger points which radiates across the
distribution of one or more branches of the
• pain rarely crosses the midline
• pain is of short duration and last for few seconds to
• in extreme cases patient has a motionless face called
• the frozen or mask like face
• presence of intraoral or extraoral trigger points
Provocated by obvious stimuli like
• Touching face at particular site
• Washing the face
The characteristic of the disorder being that the attacks do not
occur during sleep.
• CLINICAL EXAMINATION with HISTORY is
• Response to treatment with tablet of carbamazepine
• Injections of local anaesthetic agents into patients trigger
zone gives temporarily relief from pain.
• Carbamazapine and phenytoin are the traditional anticonvulsants
• The dosage of the drug used intially should be kept small to minimum
especialy in elderly patients to avoid nausea,vomiting and gastric
• Dosage should be taken at night so that adequate serum concentration
is present early morning.
• Complete blood count,liver function,platelet count should be done
prior to treatment.
• Onces the pain remission has being achieved the drug dose should be
kept at maintainence level or withdrawn and restarted if symptoms
• 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 quantites 0.5 to 2 ml
is given in peripheral branches of trigeminal nerve.
Side effect: Repeated injections may cause
• Local tissue toxicity
• Burning alcohol neuritis
Peripheral neurectomy (nerve avulsion):
• Oldest and the most effective procedure
• 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
• Temperature colder than -60 degree C,for 2-3 minutes
• Reapeated three times
• Produces WALLERIAN degeneration without destroying
the nerve sheath
• 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
• It induces pain relief in 80% of the cases.
• Also spares the ophthalmic division and the motor root. .
• A radiofrequency electrode that has the capacity to destroy
pain fibres is used.
• Alternating currents of high frequency is passed through
• It produces ionization in the biological tissues leads to
coagulation of tissues.
• A Fogarty catheter 1 to 2cm is advanced within the
meckels cave through foramen ovale.
• Inflated upto 0.75ml at the ventral aspect of theganglion
root for 1 minute.
• It destroyes the root fibres.
• Caused by Varicella zoster
• Predilection for nasociliary branch of ophthalmic division
of the trigeminal nerve
• Pustule crust permanent scar
• Acyclovir 800mg 5 times /day within 4 days of onset of rash
• Antibiotic ointments
• Systemic steroids 60mg/day
• Corneal grafting
Cavernous Sinus Syndrome
• Multiple cranial neuropathies
• Exophthalmos, ocular motor defects, sensory loss in V1 and / or
• Pupils may be spared or involved.
• causes: bacterial thrombophlebitis
tolosa hunt syndrome
• Since Trigeminal nerve is mixed nerve,
suplies mainly head and neck region. Hence
as a dental specialist one should know
throughly about itracranial and
extracranial course and distribution of
Trigeminal nerve,to diagnose the
pathologies associated with Trigeminal
nerve and for appropriate treatment.
• Anatomy head and neck ( B.D Chaurasia)
• Gray’s Anatomy
• Anatomy of cranial Nerves
• Anatomy for dental Students( A.S. Moni)
• Handbook of local anaesthesia by stanley malamed
• Textbook of oral and maxillofacial surgery(Neelima Anil Malik)
• Harrisson text of internal medicine