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1. TRIGEMINAL NERVE
The trigeminal nerve is so called because of its three main divisions i.e.
the Optalmic, Maxillary & Mandibular nerves. It is derived from the
combination of 2 Latin words, tres meaning three+ geminus meaning
twin i.e. three born together (bilaterally)
It is the largest of the cranial nerves.
It is the fifth cranial nerve
It is a mixed nerve and is sensory to the greater part of the scalp, the
teeth, and the oral and nasal cavities. Motor supply is to the MOM.
Proprioceptive nerve fibres from the masticatory and extra-ocular
muscles.
Various nuclei associated with the fifth nerve are situated within the
pons. They are:
Motor nucleus
Sensory nucleus
Mesencephalic nucleus
Spinal nucleus
THE TRIGEMINAL GANGLION:
The trigeminal nerve is continuous with the ventral surface of
the pons near its upper border by a large sensory and a small motor root.
The ganglion occupies a recess (Trigeminal or Meckel’s cave) in the dura
mater in front of the apex of the petrous temporal bone. It lies at depth of
4.5 –5 cm from the lateral aspect of the head near the posterior part of the
zygomatic arch.
It is crescentic or semilunar in shape. Medially it is related to
I.C.A & cavernous sinus, inferiorly with the motor root and the greater
petrosal nerve & the apex of the petrous temporal bone and for.lacerum.
Blood supply to the ganglion is through the ganglionic branches
of the IC & the accesory meningeal artery which enters through the
for.ovale.
MOTOR ROOT
It arises separately from the sensory root in the motor nucleus of pons. At
the semilunar ganglion it passes inferolaterally under the ganglion
towards for.ovale, through which it leaves the middle cranial fossa along
with the man.div. After it exits the skull, it unites with the sensory root
and forms a single nerve trunk. It supplies the following muscles:
1. Muscles of mastication
2. Mylohyoid
3. Ant belly of the diagastric

2. 4. Tensor tympani
5. Tensor veli palatini
SENSORY ROOT
The fibres of the sensory root arise from the cells of the trigeminal
ganglion. The branches of the unipolar cells of the trigeminal ganglio are
divided into central and peripheral branches. The central branches leave
the concave surface to enter the pons. The peripheral branches are
grouped to form the ophthalmic and maxillary nerves and sensory part of
the mandibular nerve.
OPTHALMIC NERVE
• It is the superior division of the V nerve & is the smallest.
• 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 pieces the orbital septum and ends
in the skin of the upper eyelid.
2. Frontal nerve: it is the smallest branch& appears to be the
direct continuation of the ophthalmic division. It enters the
orbit through the SOF divides into 2 branches.
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
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 the forehead.
Nasocilliary nerve: It is intermediate in size & runs
more deeply. Its branches are divided as following;
Branches in the: -
Orbit
Nasal cavity
On the face
Branches in the Orbit:

3. Long root of the cilliary ganglion: It is sensory &
passes through the ganglion without synapsing
andsupplies to the eyeball.
Long ciliary nerve: Supplies the Iris & Cornea.
Posterior ethmoidal nerve: It enters the post.
Ethmoidal canal & supplies to the mucous membrane
lining of the Post. Etmoidal & Sphenoidal paranasal
air cells.
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: -
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
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.
MAXILLLARY NERVE
• This is the second & intermediate division of the trigeminal
nerve.
• 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.

4. 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, Post.superior alveolar.
3. In the infra orbital canal: Middle sup. alveolar,
Anterior superior/ Greater alveolar
4. On the face: Palpebral, nasal,
superior labial
 Meningeal branch: It is given off near the
foramen rotundum. It supplies the duramater of
the anterior & middle cranial fossae.
 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 & pharynx.
 The zygomatic nerve: It arises in the
pterygopalatine fosssa from the maxillary
nerve.the nerve then enters the zygomatic
bone & then 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.
 The superior alveolar(dental) nerves: They
arise from the maxillary nerve before it leaves
the pterygopalatine fossa. They are:
1) 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

5. 3 molar teeth(except the mesiobuccal
root of first molar). The third branch
pierces the buccinator & supplies the
adjoining part of the gingivae & cheek
along the 3 molar teeth.
2) 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 sinus. It divides into
branches which supply the maxillary
premolars & mesiobuccal root of the first
molar teeth.
3) 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.
( The Infraorbital nerve is consisted of
the Middle & Superior alveolar dental
nerves)
 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.
 The nasal branches: They supply the skin of
the nose & tip of the nasal septum
& join the External nasal branch &
anterior ethmoidal nerve.
 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

6. glands. They are joined by the
facial nerve & form the infraorbital
plexus.
The SphenopalatinePterygopalatine ganglion
It is the largest of the peripheral ganglia. It is associated with the
greater petrosal nerve.( it is part of the 7th cranial/facial nerve).
It acts as arelay staion bn the superior salivatory nucleus in the
pons and the lacrimal gland & mucous & serous glands of the
palate, nose & paranasal sinuses.
It lies in the pterygopalatine fossa, suspended from the maxillary
division of the trigeminal nerve by 2 roots.branches from the
maxillary nerve through its ganglionic branches. They do not
establish any sympathetic connections with its cells. The
branches are: -
1. Orbital branches: They are made up of afferent
fibres & convey sensory impulses from the
periosteum of the orbit. Others supply the
mucous membrane of the Post. Ethmoidal
& sphenoidal air cells.
2. Palatine branches: they are distributed to the roof
of the mouth, soft palate, tonsil & lining
membrane of the nasal cavity. It gives of
three branches
I. Greater palatine nerve: it emerges
from the foramen medial to the 3 rd
molar, continues forward splitting
into number of branches. It is sensory
to the mucosa of the hard palate &
palatal gingivae.
II. Middle palatine nerve: This nerve
emerges from a small foramen in the
medial aspect of the pyramidal part of
the palatine bone. Sensory supply is
to the Mucous membrane of the soft
palate.
III. Posterior palatine nerve: It emerges
from a foramen slightly lateral to the

7. median palatine nerve. It contains
sensory & secretomotor fibres to the
mucous membrane of the Tonsillar
area.
3. Nasal branches: They are divided into 2 groups: -
I. Posterior superior lateral nerves:
they supply they Posterior part of the
nasal conchae
II. Nasopalatine(Sphenopalatine)
nerve: It passes downwards &
forwards between the periosteum
&mucous membrane in the region of
the vomer, continues downwards &
forwards, reachs the floor of the nasal
cavity.
Descends into the incisal canal to
appear in the anterior part of the hard
palate & supplies the mucous
membrane of the premaxilla.
4. Pharyngeal branches: This branch supplies
sensory & secretory fibers to the
mucous membrane of the
nasopharynx, behind the opening of
the auditory tube. It arises from the
posterior part of the ganglion & passes
through the palatovaginal canal along
with the pharyngeal branch of the
maxillary artery.
MANDIBULAR NERVE
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 &
semilunar ganglion & almost immediately emerges out through the
foramen ovale( of the sphenoid) & 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 posterior trunk.

8. 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 various brancnes given off are as follows: -
1) Branches of the undivided nerve.
i. Meningeal branch/nervus spinosus.
ii. Nerve to the medial pterygoid
2) Branches of the divided nerve:
A) Anterior division:
i. Buccal nerve
ii. Massetric nerve
iii. Deep temporal nerve
iv. Nerve to the lateral pterygoid.
B) Posterior division:
i. Auriculotemporal nerve
ii. Lingual nerve
iii. Inferior alveolar nerve
1) Undivided nerve branches
i. Meningeal nerve:
• It enters the skull through the foramen spinosum
along with MMA.
• It has anterior & posterior divisions that supply the
dura of the middle &
ant.cranial fossae.
ii. Nerve to the medial pterygoid:
 It is a slender branch that enters the deep surface of
the muscle.
 It also gives 1-2 filaments to the tensor tympani &
the tensor veli
palati
muscles.
2) Divided nerve branches.
A) Anterior division: It has 1 sensory branch. i.e.
long buccal nerve &3 branches that are motor
to the massetric, deep temporal & lateral
pterygoid muscles.
i. The buccal nerve:

9. • It passes between the 2 heads of the
lateral pterygoid & descendsbeneath
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
nerve.
• It supplies the skin over the ant. part
of the buccinator & mucous
membrane lining the buccal surface
of the gum.
ii. 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 joint.
iii. 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.
iv. The nerve to the lateral pterygoid.
• These are also 2 in number one for
each head.
(2) Posterior division:
The posterior trunk is mostly sensory but
receives a few filaments from the
motor root.
i. The Auriculotemporal nerve:
• The auriculotemporal nerve arises
by a medial & lateral roots, that
enclircle theMMA & unite behind it
just below the foramen spinosum.
• The united nerve passes backwards,
deep to the lateral pterygoid muscle

10. & 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.
Communications of the nerve:
 2 roots of the nerve:- both
tghese roots receive
communications from he OTIC
ganglion. They are
postganglionic secretory fibres
to the Parotid gland.i.e they
control the secretions from the
gland
 Communicating branches to the
postganglionic sympathetic
fibres:- These are vasomotor
fibres that pass to the parotid
through the auriculotemporal
nerve.
 Communicating branches to the
facila nerve: These are purely
sensory from the
Auriculotemporal nerve.
Branches of the nerve:
i. Parotid branches
ii. Articular branches--- to
the TMJ.
iii. Auricular branches---to
the skin of the helix &
tragus.
iv. Meatal branches-----
Meatus of the tymphanic
membrane

11. v. Terminal branches----
Scalp over the temporal
region
Lingual nerve
This is the smaller of the 2 branches of
the posterior division,
It passes medial to the lateral pterygoid &
it lies between the ramus of the mandible
& the muscle in the pterygomandibular
space.
It gives off sensory fibresto the tonsil &
the mucous membrane of the posterior
part of the oral cavity.
In the pterygomandibular space, it lies
parallel to the inferior alveolar nerve, but
medial & anterior to it.
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 the
the side of the 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.
Communication of the facial nerve
(Chorda tymphani)
As the lingual nerve passes
medially to the lateral pterygoid, it is
joined by the chorda tympani. This nerve
conveys secretory fibres from the facial
nerve. The parasympathetic secretory
fibres control the submandibular &
sublingual salivary glands.

12. Inferior alveolar nerve.
It is the largest terminal branch of
the posterior division of the mandibular nerve.
The nerve descends deeep to the lateral
pterygoid muscle 7& 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 a[pical
foramena of the teeth to supply the pulp
mainly as well as the periodontium.
Branches of the nerve
Mental nerve: it supplies to the skin of
the chin & the mucous membrane as well
as the skin of the lower lip.
Incisive branch: continues anteriorly
from the mental nerve in the body of the
mandibleto form the incisive plexus &
supplies the canine & incisors.
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.
Autonomic ganglia associated with the
mandibular division
Submandibular ganglion:
It is a small ovoid body that is
suspendedfrom the lingual nerve above
the submandibulat salivary gland. The

13. preganglionic parasympathetic fibres
reach the ganglion arising from the
superior salivatory nucleus, reaching
through the facial, chorda tympani & the
lingual nerve. Post ganglionic fibres are
conveyed through the submandibular,
sublingual & anterior lingual salivary
glands.
The sensory nerves reach the
gangliothrough the lingual nerve.
Sympathetic fibres are derived from the
plexus around the facial artery & contain
post ganglionic fibres arising in the
superior cervical ganglion. They provide
secretomotor fibres to the submandibular
& sublingual galands.
Otic ganglion
It is a flattened ovoid body located on the
medial side of the undivided nerve. It is
situated below the for. ovale & the
MMA.
It has 2 main roots:-
1) Parasympathetic preganglionic
(secretory) fibres: they arise from
the inferior salivatory nucleus.the
efferent fibres pass by way if the
glossopharyngeal nerve through
the jugular canal.below the canal it
passes through the tympanic
branch of the glossopharyngeal
nerve( Jacobson’s nerve), passing
through the tympanic plexus & the
lesser petrosal branch to reach the
Ganglion.( the lesser superficial petrosal
nerve is the parasympathetic root of the
otic ganglion) the postganglionic fibres
pass through the auriculotemporal nerve.
2) Sympathetic root: It is made up of
the postganglionic fibres that have
originated in the superior cervical

14. sympathetic ganglion & the plexus
of the MMA. The fibres pass
through the ganglion uninterrupted.
These fibres reach the parotid thru
the auriculotemporal nerve.
Afferent of sensory nerves come
from the parotid through the
auriculotenporal nerve.