Trigeminal nerve and its importance in max-fac surgery
Nucleus of trigeminal
Ganglions of trigeminal
Divisions of trigeminal nv
Maxillary branch & associated ganglion
Mandibular branch & associated ganglion
Commonest clinical applications
Clinical implication of
Lesion associated with intracranial part of
It is the 5th cranial
Largest cranial nerve
It is the main
sensory nerve of the
face and head
It was described by
Fallopius & Meckle in
As this nerve has
so that called as
This term is coined
It is derived from 1st branchial arch
So that the structures derived from the 1st
branchial arch are innervated by this nerve.
The trigeminal nerve contains both sensory and
The somata of, motor neuroblasts originate
with in neuroepithelium,
sensory neuroblasts --- derived from the neural
crest and from ectodermal placodes.
This three roots are basically sensory by nature
Along with this sensory branch their is a motor
root of this trigeminal nerve
It is mixed nerve.
Contains 170,000 sensory fibres
7,700 motor fibres
The 3 divisions have approx ophthalmic 26,000
Larger Sensory Root
Smaller Motor Root
3 primary divisions:
Ophthalmic ( V1) - sensory
- innervates the upper portion of the face
Maxillary (V2)- sensory – innervates the mid face
Mandibular (V3) -sensory+motor – innervates the
lower facial region
Main sensory nuclei
lies in pons lat to motor nucleus
relays discriminitive touch
continuous superiorly with main
sensory nucleus and extends
inferiorly through medulla
oblongata and into upper part
of spinal cord as far as second
where its continuous with
associated with the
transmission of discriminative
(fine) tactile sense from the
associated with the
transmission of tactile sense,
as well as dental pain
associated with the
transmission of nociception
and thermal sensations from
V1 – pars caudalis
V2- pars interpolaris
V3- pars oralis.
first order sensory
cell body of
from muscles of
reflex arc .
situated in midbrain just
lat to aqueduct
of mastication and
tensor tympani and
Located in pons
med. to princi sen.
SEMILUNAR OR GASSERIAN GANGLION.
Sensory ganglion corresponding to DRG of spinal
Cresentric in shape with convexity anterolat.
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 lat to post. Part of lat wall of the
5 cm deep to the preauricular point
COVERINGS: covered by dural pouch = MECKLES CAVE
OR CAVUM TRIGEMINALE.
Roof- 2 layers of dura
floor- 1 dural and 1endosteal dural layer.
cave lined by pia and arachnoid thus the
ganglion is bathed in CSF.
ARTERIAL SUPPLY: ganglionic branches of ICA, middle
meningeal artery and accessory meningeal artery.
SUPERIORLY: sup petrosal sinus, free margin of tentorium cerebelli
INFERIORLY: motor root , greater petrosal nerve, petrous apex
MEDIALLY: post. Part of lat. Wall of cavernous sinus
ICA with its sympathetic plexus
LATERALLY: uncus of temporal lobe
Give off minute branches -
tentorium cerebelli and to dura
mater in the middle cranial
From its convex border three
large nerves arises
Ophthalmic and Maxillary -
exclusively of sensory fibers.
Mandibular is joined outside
the cranium by the motor root.
Motor root runs - front and medial to the
sensory root & passes beneath the ganglion.
Leaves the skull - foramen ovale - immediately
below this foramen - joins the mandibular nerve
Supplies : cornea,conjuctiva,upper
lid,forehead,ant part of scalp,nose.
emerges from trigeminal ganglion
lat wall cavernous sinus
3 branches in ant part of cavernous sinus
nasocilliary, frontal, lacrimal
superior orbital fissure
Passes into orbit through lat
compartment of the sup orbital
fissure outside the tendinous
Receives communicating branch
from trochlear nerve
Receives branch from
Passes along sup border of LR
with lacrimal art
Sensory to lat conjunctiva,UL,
Enters through lat part of sup orbital fissure outside tendinous ring
Passes forward between roof of orbit and LPS
Divides midway into SUPRATROCHLEAR NERVE
SUPRATROCHLEAR N SUPRAORBITAL N
Curves around sup med
margin of orbit
conjunctiva and UL
lower part of forehead
Lies betwn frontalis
Lies beneath frontalis
Divides in med and lat
scalp upto vertex,
mucous membrane of
Passes through med part of sup.
Orbital fissure within the tendenious
ring betwn the two div of
Crosses from lat to med above Optic
Nerve with ophthalmic art
Runs along med wall of orbit betwn
SO and MR
Divides into terminal branches ANT
ETHMOIDAL NERVE and
5 branches in orbit.
1. Communicating branch to cilliary
passes along short cilliary nerves.
carries symp fibres from IC plexus and
sensory fibres from the eyeball.
2. LONG CILLIARY NERVES : 2 or 3.
run along med side of the ON
pierce sclera and supply cornea, iris,
carry pain temp and touch.
sympathetic motor supply to
3. POST ETHMOIDAL NERVE:
passes thru post ethmoidal foramen
to supply the ethmoid and sphenoid
4. INFRATROCHLEAR NERVE:
smaller terminal branch
emerges below trochlea
appears on face above med angle the eye.
supplies: upper half of external nose
skin of med most part of UL andLL
5. ANT ETHMOIDAL NERVE:
larger terminal branch
course: ant ethmoidal foramen and canal
into ant cranial fossa on sup surf of cribriform plate
Through slit lat to crista galli into nasal cavity
Med internal nasal branch lat internal nasal branch
Supplies ant nasal septum supplies ant part lat
nasal cavity emerges as
external nasal nerve to
skin of ala,vestibule,and
tip of nose
CILIARY GANGLION (Lenticular ganglion)
Situated - back part of the orbit - on the
lateral side of the ophthalmic artery.
Its roots are 3 in number and enter its
Long or Sensory Root (sympathetic root)
-Derived from the nasociliary nerve.
-carries postganglionic fiber from sup.cervical sympathetic
- innervate radial fiber of dilator pupillae muscle in iris
Short or Motor Root (parasympathetic root)
- Derived from the branch of the oculomotor nerve
- these preganglionic fiber along with the post ganglionic
fiber form short ciliary nerve which innervate sphinctre pupillae
& ciliary muscle of iris
- fsensory root of nasocilliary nerve
- it causes pupil to dilate
- it causes pupil to constrict
- changes the convexity of lense
Second division of the trigeminal nerve.
Is a sensory nerve.
It begins - middle of semilunar ganglion as a flattened
plexiform band, passing horizontally forward - leaves the skull
, foramen rotundum.
Then crosses - pterygopalatine fossa - enters the orbit through
the inferior orbital fissure - it traverses the infraorbital groove
and canal in the floor of the orbit and appears on the face -
Branches of Maxillary Nerve
In the cranium Middle Meningeal Nerve
In the Pterygopalatine
In the Infraorbital Canal Anterior Superior
Middle Superior Alveolar
On the Face Inferior Palpebral
From middle of the gasserion ganglion it travels
anteriorly & downwards
Branch Within cranium –Middle meningial nerve
Run along with middle meningial artery,
-- sensory innervation to dura matter.
Exit cranium from foramen rotundum
Lies within inferior orbital
Give two branches
Supplies skin of temporal
region after peircing temporal
fascia 2 cm above zygoma
Gives communicating branch
to lacrimal N suppling
fibres to lacrimal gland
Supply skin of face
Two short nerve trunk
Unite with Pterygopalatine ganglion
Triangular or heart-shaped, of a
Situated just below the maxillary
nerve as it crosses the fossa.
It receives a sensory, a motor, and
a sympathetic root.
Redistribute in 4 branches
Periosteum of orbit
Post.ethmoid cells & sphenoid sinus
Secretory to lacrimal gland
Posterior superior lateral nasal branch
Carry sensation from mucous memb.of nasal septum & post.ethmoid cells
Mucous membrane on vomer
Come out through incisal canal & supply premaxilla
Emerge from greater palatine foramen
Carries secretory & sensory fibers to mucous of hard palate & palatal gingivae
Emerge from small foramen of pyramidal part of palatine bone
Supply sensory & secretory fibers to soft palate
Posterior/ Lesser palatine
Emerge from lesser palatine foramen
Supply sensory and secretory fibers to tonsillar area
Sensory and secretory fibers to nasopharynx
External to bone
Buccal gingiva of maxillary molar
Enters into maxilla
Sensory to maxillary sinus,
maxillary molar (except mesio
buccal root of 1st max.molar)
MSA nerve ASA nerve
1st & 2nd PM region supplies antarior
Mesiobuccal root of 1st M maxillray sinus &
supplies 1 to 3.
PDL, buccal soft tissue, bone
(in 30% cases, it is absent then
Psa & Asa
Provides its supplies).
In the face (emerge through inferior orbital foramen)
Inferior palpebral external nasal sup. Labial
Skin of lower eyelid skin of lateral skin,mucous
aspect of nose memb.,upper
Motor root- from motor sensory root- gasserian ganglion
nucleus in pons
exit through foramen ovale in grt. Wing of sphenoid
from trunk in infra-temporal fossa
travels between lat. Pterygoid and otic ganglion laterally and
tensor palatine medially anteriorly to med. Meningeal A.
small ant. Division large post. division
N. to med. Pterygoid
Deep temporal N.
N. to lat. Pterygoid
Through foramen spinosus
Dura mid cranial fossa
Nerve to med. Pterygoid
Supplies medial pterygoid
Through otic ganglion without interruption to
Nerve to lat pterygoid
Massetric nerve- lies sup to lat pterygoid,inf to
temporalis tendon and ant to TMJ.
supplies masseter and TMJ
Buccal nerve-is the only sensory branch of ant div.
travels betwn 2 heads of lat pterygoidand emerges
in cheek at ant border of masseter. Supplies skin
and mm of cheek.
Deep temporal nerve -the 2 nerves ascend deep to
lat pterygoid and supply temporalis.
Arises from 2 roots which encircle the middle
The trunk passes post to lat pterygoid betwn neck of
mandible and sphenomandibular lig sup to 1st part
of maxillary art.
Lies behind the TMJ close to the parotid
Ascends behind sup temporal vessels and then in
temporal region divides into superficial temporal
Branches of auriculotemporal nerve
auricular branches -supply
tragus,upper part of aurical,roof
of ext auditory meatus,anterosup
part of tympanic memb
Superficial temporal branches-supply
skin of temple
Articular branches-supply the
2. Inferior alveolar nerve:
Is mixed nerve
Passes between mandible and sphenomandibular lig inf
to lat pterygoid,
Enters mandible through mandibular foramen to run in
a bony canal below the teeth
Branches: to molars and premolars
mylohyoid nerve-mylohyoid and ant belly
communicating nerve to lingual nerve
3.Lingual nerve: lies ant to inf. alveolar n between lat
pterygoid and tensor palatini
receives chorda tympani (SVA)
Emerges from inf border of lat pterygoid to lie betwn ramus
and med pterygoid
Between origins of sup constrictir and mylohyoid
1 cm below and behind 3rd molar in gingiva
Rests on hypoglossus lat to the tongue where it is
related to the submandibular ganglion
Gives sensory supply to presulcal tongue ,floor of mouth,
mandibular gums,and carries proprioception from tongue.
Branches of lingual nerve and its
SUBMAXILLARY / SUBMANDIBULAR
Small size & fusiform in shape.
Situated above the deep portion of the
submaxillary / Submandibular gland.
Arise - from the lower part of the
Supply - mucous membrane of the mouth
and the duct of the submaxillary gland.
Small, oval shaped,reddish-gray color ganglion
- situated immediately below the foramen ovale.
Lies - medial surface of the mandibular nerve.
A filament to the
Tensor veli palatini.
Responsible for carrying
Utilize the 3-neuron sensory system
Utilize the contra lateral ventral trigeminothalamic tract
The most commonly anesthetized nerves in dentistry
are branches or nerve trunks associated with the
maxillary and mandibular divisions of the trigeminal
The maxilla’s relatively porous alveolar bone allows
for the use of straightforward local anesthetic
techniques of paraperiosteal field blocks or
The mandible is different. The outer layer of cortical
bone is thick and nonporous and thus normally
requires the use of a nerve block at a site away from
the teeth being treated.
Techniques of Maxillary Regional
The techniques most commonly employed in maxillary
• Supraperiosteal (local) infiltration
• Periodontal ligament (intraligamentary) injection
• Posterior superior alveolar nerve block
• Middle superior alveolar nerve block
• Anterior superior alveolar nerve block
• Greater palatine nerve block
• Nasopalatine nerve block
• Local infiltration of the palate
• Intrapulpal injection
Shingles and varicella-zoster: The trigeminal
ganglion, as any sensory ganglion, may be the site
of infection by the herpes zoster virus causing
shingles, a painful vesicular eruption in the sensory
distribution of the nerve.
Trigeminal neuralgia (tic douloureux): This is severe
pain in the distribution of the trigeminal nerve or
one of its branches, the cause often being
unknown. It may require partial destruction of the
Malignant tumours of the mucous lining of the
ethmoid air cells may expand into the orbits,
damaging branches of opthalmic nerve. This
may lead to displacement of the orbital
contents causing proptosis and squint, and
sensory loss over the anterior nasal skin.
Trauma to the nose may damage the nasociliary
nerve. Sensory loss of the skin down to the tip
of the nose may result.
Corneal reflex: When the cornea is touched, usually
with a wisp of cotton, the subject blinks. This tests
V and VII. The nerve impulses pass through cornea
and then through nasociliary nerve to the brain.
Trauma to the supraorbital margin may damage the
supraorbital and supratrochlear nerves causing
sensory loss in the scalp.
Infraorbital injuries (malar fractures):
Trauma to infraorbital margin may cause sensory loss
of infraorbital skin.
Maxillary antrum tumours:
Malignant tumors of the mucous lining of the
maxillary antrum may expand into the orbit,
damaging branches of maxillary nerve, particularly
the infraorbital. This may lead to anaesthesia over
the facial skin.
Maxillary sinus infections: Infections of the
maxillary sinus may cause infraorbital pain or may
cause referred pain to other structures supplied by
maxillary nerve e.g. upper teeth.
Maxillary teeth abscesses: The roots of the
maxillary teeth (especially the second molars) are
intimately related to the maxillary sinus. Root
abscesses are painful.
Lingual nerve: Careless
extractions of the third
lower molar, abscesses of
its root, or fractures of
the angle of the mandible
may all damage the lingual
nerve. This may result in
loss of somatic sensation
from the anterior portion
of the tongue and loss of
Protection of lingual nerve::
during surgical removal of
mandibular third molar-
Inferior alveolar nerve: Trauma to the
mandible may damage or tear
the inferior alveolar nerve in the
mandibular canal leading to
sensory loss distal to the lesion.
Mumps: Mumps is inflammation of the parotid
gland causing tension in the parotid capsule which
is innervated by the auriculotemporal nerve. It
gives both local tenderness and referred ear ache.
Submandibular duct: The intimate relationship between the
submandibular duct and the lingual nerve is significant in duct infections
and surgery. If the lingual nerve were damaged during a submandibular
surgery, there would be sensory loss, both somatic and taste, in the
anterior portion of the tongue.
Referred pain to the ear: Disease of the TMJ or
swelling of the parotid gland may cause ear ache
because of referred pain. Also, pain from the lower
teeth, oral cavity and tongue may be referred to
Superficial temporal artery biopsy: The auriculotemporal
nerve accompanies the superficial temporal artery on the temple. In cases
of temporal arteritis, the nerve is anaesthetized so that the overlying skin
can be incised to obtain a biopsy of the artery.
Infections and neoplasia most commonly involve
the peripheral divisions of the trigeminal nerve
rather than the intracranial part.
The Meckel’s cavity can be involved either by
extrinsic or intrinsic disease. Extrinsic lesions,
usually bony metastasis, chordoma, or
chondrosarcoma, destroy adjacent bone as they
extend toward the Meckel’s cavity. Intrinsic lesions
simply expand the Meckel’s cavity.
Pituitary fossa and cavernous sinus lesions may
extend to the Meckel’s cavity or involve the
cavernous portion of the trigeminal nerve divisions
The trigeminal nerve has three sensory and one
motor nuclei. The sensory nuclei are the principal,
mesencephalic, and spinal sensory.
The cervical extension of the spinal sensory nucleus
explains the relation of upper cervical disk
herniation and its association with trigeminal
Multiple sclerosis, glioma, and infarction are the
most common brainstem and upper cervical cord
lesions resulting in fifth cranial nerve symptom.
Less common lesions include metastasis, cavernous
hemangiomas, hemorrhage, and arteriovenous
Rarely, rhombencephalitis may develop as a result
of retrograde extension of herpes simplex virus
type 1 from the trigeminal ganglion into the
Consists of flushing and
sweating of the ipsilateral
face in the distribution of
the auriculotemporal nerve
upon eating or tasting.
It is occasionally seen
following injury or infection
of the parotid gland area .
It is also known as the Reader
Syndrome and is a rare
disorder produced by tumors
arising in the semilunar
Characterised by trigeminal
neuralgia at the onest ,
followed by facial anesthesias
on the affected side.
The muscles of mastication
are found weakened or
In conclusion, a variety of conditions may involve
the different segments of the trigeminal nerve.
Knowledge of its anatomic course and its
application allows an understanding of disorders
involving the brainstem, the nerve parts and
adjacent skull base.
Monhem’s Local Anaesthesia
and Pain Controll in Dental
Practice; C.Richard Bennett,
7th Edition; CBS publication
Cranial Nerves Functional
Monkhouse;2nd edition 2006;
Cambridge university press.
Sicher and DuBRULS ORAL
ANATOMY by E. LLOYOD
EuroAmerica, Inc. Publishers
Gray’s anatomy, Henry Gray;