TRIGEMINALNERVE
PRESENTED BY:
DR ANKITA RAJ(PROFESSOR)
DEPT OF ORAL & MAXILLOFACIAL SURGERY

INTRODUCTION:
• It is the largest cranial nerve.
• It is the fifth cranial nerve.
• It is a mixed nerve, i.e., contains both sensory and motor fibers.
• It is attached to lateral part of pons by its two roots: motor and sensory.
• It conveys both exteroceptive and proprioceptive impulses.

Exteroceptive impulses (touch, pain and thermal senses) are transmitted from:
- Extensive portions of cranial dura
- Skin of face and forehead
- Mucous membrane of nasal cavities
- Nasal sinuses
- Oral cavity
- Teeth
- Anterior two third of the tongue
- Floor of the mouth

Proprioceptive impulses (deep pressure and kinesthesis) are transmitted from:
- Teeth
- Periodontium
- Hard palate
- Temporomandibular joint receptors

SENSORYAND MOTOR ROOT OF TRIGEMINAL
NERVE

MOTOR ROOT:
Origin: Motor nucleus in upper pons
It pass from pons along the medial side of semilunar ganglion, then pass below to
foramen ovale through which it leaves the middle cranial fossa along with mandibular
division.
Below base of skull it joins mandibular division to form a single trunk.
It supplies: Muscles of mastication
Tensor tympani
Tensor veli palatini
Anterior belly of digastric
Mylohyoid

SENSORY ROOT:
Its fibres arise from Semilunar (gasserian) ganglion.
They enter the brain stem through the lateral side of the pons.
The Semilunar ganglion is developed from the neural crest. It is located in the Meckel’s
cavity, near the apex of the petrous part of temporal bone.
It contains unipolar neurons with which it forms the central and peripheral processes.
The peripheral branches form the ophthalmic, maxillary and mandibular branches.
The central branches form the sensory root of the trigeminal nerve.
The central branches leave the semilunar ganglion and pass back to enter the pons where
they divide into ascending and descending fibres.

The ascending fibers terminate in the upper sensory nucleus in pons lateral to the motor nucleus.
It is the main sensory nucleus of the trigeminal nerve. These ascending fibres conveys light, touch,
tactile discrimination, sense of position and passive movement.
The upper or main nucleus gives rise to the dorsal trigeminothalamic tract.
The Spinal (bulbospinal) nucleus gives rise to
ventral trigeminothalamic tract. These fibres convey
pain and temperature.
The Mesencephalic nucleus receives proprioceptive
impulses from the temporomandibular joint, the
periodontal membrane, the maxillary and mandibular
teeth and hard palate.

NUCLEI OF TRIGEMINAL NERVE

DIVISIONS OF THE TRIGEMINAL NERVE:
Three large nerves proceed from the convex border of the semilunar ganglion:
A. Ophthalmic nerve (V1)
B. Maxillary nerve (V2)
C. Mandibular nerve (V3)

OPHTHALMIC NERVE:
First division of trigeminal nerve
It is the smallest of the three division
Its fibres are sensory
Course: It leaves the anterior medial part of the ganglion and passes forward in the lateral part
of cavernous sinus. It then enters the orbit through superior orbital fissure.
In middle cranial fossa, nervous tentorii branches from V1 supply: dura
As it pass from cavernous sinus, it divides into three branches: Lacrimal nerve
Frontal nerve
Nasociliary nerve

OPTHALMIC NERVE DIVISION

LACRIMAL NERVE:
Smallest branch of V1
Sensory nerve
Course: Passes into orbit at lateral angle of superior orbital fissure, then it pass in antero-lateral
direction to reach the lacrimal gland.
Supply: sensory fibers to – Lacrimal gland
Adjacent conjunctiva

FRONTAL NERVE:
Largest branch of ophthalmic nerve
Enters the orbit through superior orbital fissure.
At about the middle of the orbit, it divides into: a) Supraorbital nerve
b) Supratrochlear nerve
Supraorbital nerve: Largest branch of frontal nerve
Pass forward and leaves the orbit through supraorbital foramen or notch to supply:
- Skin of upper eyelid
- Forehead
- Anterior scalp region to skin of forehead

FRONTAL NERVE:

Supratrochlear nerve: Passes toward the upper medial angle of the orbit where it pierces the
fascia of upper eyelid to supply: Skin of upper eyelid
Upper medial portion of the forehead

NASOCILIALRY NERVE:
 Third branch of V1
 Enters orbit through superior orbital fissure
 It’s branches are divided into those: a) Arising in orbit
b) Arising in nasal cavity
c) Terminal branches on the face on the face
Branches arising in orbit:
A) Long root of ciliary ganglion: supply the eyeball
B) Long ciliary nerve: supply the iris and cornea
C) Posterior ethmoid nerve: supply to the- mucous membrane of cells
- frontal sinus
D) Anterior ethmoid nerve: supply -mucous membrane of anterior ethmoid cells
-frontal sinus

• Anterior ethmoid nerve divides into two in the upper part of nasal cavity:
i) Internal nasal branches: It again divides into two:
Medial or septal branches Lateral branches
supply supply
Mucous membrane of that area Mucous membrane of anterior ends of
superior and middle nasal conchae and to
the anterior lateral nasal wall.
ii) External nasal branches: supplies- the skin over the nose
- the skin over the ala of the nose

Branches arising in the nasal cavity: Supply the mucous membrane lining the cavity
Terminal branches of V1 on the face: Supply- skin of medial parts of both eyelids
- lacrimal sac
- lacrimal caruncle
- skin over the side of the bridge of nose

MAXILLARY DIVISION
It originates in the middle of the semilunar ganglion and continues forward in the lower part
of cavernous sinus. It then leaves the cranial fossa through foramen rotundum and enters the
pterygopalatine fossa.
It enters orbital cavity through inferior orbital fissure where it turns laterally in infraorbital
groove on the orbital surface of maxilla.
It then continue forward through infraorbital foramen to emerge on the anterior surface of
maxilla.
In it’s course it gives off branches in four regions:
In the middle cranial fossa In pterygopalatine fossa In infraorbital groove and canal Terminal
branches
on the face

a) Branches given off in middle cranial fossa: In the middle cranial fossa, a small branch the
middle meningeal nerve supply the dura with sensory fibers.
b) Branches in the pterygopalatine fossa:
Zygomatic Pterygopalatine Posterior superior alveolar
Nerve nerves branches

MAXILLARY DIVISION

i) Zygomatic nerve: Divides into two parts: Zygomaticofacial nerve
Zygomaticotemporal nerve
Zygomaticofacial nerve- supply to skin over the prominence of zygomatic bone
Zygomaticotemporal nerve- supply to the skin over the anterior temporal fossa region
ii) Pterygopalatine (sphenopalatine) nerves: divided into three groups:
Orbital branches Nasal branches Palatine branches

Orbital branches: Supply- periosteum of the orbit
- mucous membrane of part of ethmoid cells and the sphenoid sinus
Nasal branches: divides into-
- Posterior superior lateral nasal branches: supply mucous membrane of nasal septum and
posterior ethmoid cells.
- Medial or septal branches: supply to mucous membrane over vomer bone
Palatine branches: divide into three strands:
- Greater or anterior palatine branches: It emerges on hard palate by emerging from greater
palatine foramen.
supply: Major part of hard palate and palatine
gingiva

- Middle palatine nerve: It emerges from lesser palatine foramen
supply the soft palate
- Posterior palatine fibres: Emerges from lesser palatine foramen
supply the tonsils and mucous membrane of tonsillar area
iii) Posterior superior alveolar branches: Supply the- maxillary molars and their gingiva
- mesiobuccal root of the first molar(72%
cases)
- mucous membrane of maxillary sinus
iv) Branches in infraorbital groove and canal: It is called as the infraorbital nerve.
- middle superior alveolar nerve: supply - maxillary bicuspids
- mesiobuccal root of first molar
- lining of maxillary sinus

- Anterior superior alveolar nerve: supply- maxillary incisors and cuspids
- lining of maxillary sinus
V) Terminal branches of maxillary division on face: Three terminal branches are:
Inferior palpebral Lateral nasal Superior labial
supply supply supply
skin of lower eyelid skin of the side of nose skin of upper lip

Autonomic ganglion associated with maxillary division of trigeminal nerve
Sphenopalatine ganglion is associated with great superficial petrosal nerve and is a part of
seventh cranial nerve.
The ganglion is stellate and lies deep in the temporal fossa, suspended from the maxillary
division by two roots.
Branches from the spenopalatine (pterygopalatine) ganglion:
1. Orbital branches: convey impulses from periosteum of the orbit.
2. Nasal branches: They divide into two groups:
a) Posterior superior lateral nerves: innervate mucosa over posterior part of nasal conchae.
b) Nasopalatine (Long sphenopalatine) nerve: supply the anterior part of hard palate and
mucous membrane of premaxilla.
3. Palatine branches: It divides into three branches:

a) Greater palatine nerve: Emerge from greater palatine foramen.
It carries sensory and secretory fibers to major part of mucous membrane of the hard palate
and palatal gingiva.
b) Middle palatine nerve: Supply sensory and secretory fibers to the mucous membrane of the
soft palate.
c) Posterior palatine nerves: Supply sensory and secretory fibers to the mucous membrane of
the tonsillar area.
4. Pharyngeal branch: Convey sensory and secretory fibers to the mucous membrane of the
nasopharynx about the opening of the auditory tube.
5. Secretory fibers to lacrimal gland: They control the secretion of the lacrimal gland.

MANDIBULAR DIVISION (V3):
It is largest of the three divisions.
It is formed by the union of large sensory(afferent) and small motor(efferent) bundles of fibres.
The sensory root fibres are peripheral extensions of unipolar cells located in semilunar ganglion.
The motor root fibres are derived from the motor cells located in medulla oblongata. These
fibres become incorporated with sensory fibres in mandibular trunk.
The motor root joins the sensory root after the latter leaves the semilunar ganglion. The two
roots pass side by side in the dura of middle cranial fossa to the foramen ovale.
Leaving the foramen ovale the two roots unite to form a short single trunk.
It’s branches can be divided into two divisions:
Branches from the undivided nerve Branches from the
divided nerve

MANDIBULAR DIVISION (V3):

A) Branches from the undivided nerve:
Nervous spinosus Nerve to internal pterygoid muscle
supply supply
-dura and mastoid cells Branch of motor root passes to innervate:
- internal pterygoid muscle
- tensor tympani muscle
- tensor veli palatini muscle

B) Branches from the divided nerve: The trunk separates into two parts:- Anterior division
- Posterior division
i) Anterior division: Smaller than posterior division. Receives both sensory and motor fibers. It
divides into:
Pterygoid nerve Masseter nerve Nerves to the temporal muscle Buccal nerve
divides into
-Anterior deep temporal nerve
-Posterior deep temporal nerve
Pterygoid nerve: Provide motor nerve supply to external pterygoid muscle.
Masseter nerve: Supply to masseter muscle.
Nerve to the temporal muscle:
-Anterior deep temporal nerve: supplies deep part of anterior portion of temporal muscle

-Posterior deep temporal nerve: It passes upward to the deep part of temporal muscle.
Buccal nerve: supply sensory fibers to- buccal gingivae about the mandibular molars
- mucous membrane of lower part of buccal vestibule
- almost the entire mucosa of cheek
-buccinator muscle
ii) Posterior division: It is mainly sensory but also carries some motor fibers. It branches into:
Auriculotemporal nerve Lingual nerve Inferior alveolar nerve
Parotid branch
Articular branch
Auricular branch
Meatal branch
Terminal branches

1. Auriculotemporal nerve: It arises by a medial and lateral root.
Communications: Each root receives communicating fibers from the otic ganglion. They
control secretion of parotid gland.
Branches:
-Parotid branch: It gives sensory, secretory and vasomotor fibers to the gland.
-Articular branch: Sensory fibers from auriculotemporal nerve pass from the
auriculotemporal nerve and enter the posterior part of temporomandibular joint.
-Auricular branches: Supply sensory fibers to skin of the helix and tragus.
-Meatal branches: Supply skin lining the meatus and tympanic membrane.
-Terminal branches: Supply scalp over temporal region.

2. Lingual nerve: It passes medially to lateral pterygoid muscle, lies in the
pterygomandibular space in between internal pterygoid muscle and ramus of
the mandible.
- Here it lies parallel to the inferior alveolar nerve.
- Supply to: - anterior two third of the tongue
- floor of the mouth
- gingiva on the lingual surface of the mandible

3. Inferior Alveolar Nerve:
It is a mixed nerve.
Branches:
-Branches to lower teeth and gums: Supply dental pulps of lower teeth and periodontal
membrane of lower teeth.
-Mental nerve: Transmits sensory fibers to the skin of the chin and lower lip.
: It also supplies to mucous membrane lining lower lip
-Incisive branch: It supplies the incisors and the cuspids.
-Mylohyoid branch: It contains both sensory and motor fibers.
:It sends motor fibers to mylohyoid muscles and anterior belly of
the digastric muscle.

APPLIED ANATOMY
Trigeminal neuralgia: It is characterized by attacks of severe pain in the areas of
distribution of maxillary or mandibular divisions. Maxillary nerve is more frequently
involved.
The trigeminal ganglion harbors the herpes zoster virus causing shingles in the
distribution of the nerve.
Flaccid paralysis of muscles of mastication in injury of mandibular nerve leading to
decrease strength for biting.
Hypoacusis, partial deafness to low pitched sounds due to paralysis of tensor tympani
muscle.

References:
Monheim’s Local Anesthesia and Pain Control in Dental Practice- Seventh edition
Handbook of Local anesthesia by Stanley F. Malamed- Sixth edition
B. D. Chaurasia’s Human Anatomy volume 3- Sixth edition

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