veruy good for beginners

2. TRIGEMINAL NERVE
• GUIDED BY:
• DR. NEEMA SHETTY
• DR. ADITI MATHUR
• DR. ASHISH BALI
• DR.TRISHI
PRESENTED BY:
DR. DHARITRI DESAI
1STYEAR PG

3. CONTENTS
 INTRODUCTION
 DIVISION OF NERVOUS SYSTEM
 STRUCTURE OF NERVOUS TISUE
 CLASSIFICATION OF CRANIAL NERVES
 EMBRYOLOGY OFTRIGEMINAL NERVE
 TRIGEMINAL NERVE
-NUCLEI
-GANGLION
-BRANCHES & ITS COURSE
-APPLIED ANATOMY
 CONCLUSION
 REFERENCES

4. INTRODUCTION
NERVOUSSYSTEM
 Human organ system that co-ordinates all of the body’s voluntary &
involuntary actions, by transmitting electrical signals to and from
different parts of the body.
 It controls and regulates the internal activities of the body as well as
responds to the external changes & helps the individual to adapt and
digest in given surrounding.
 Based upon special properties of sensitivity, conductivity and
responsiveness of the nervous system.

5. DIVISION OF NERVOUS SYSTEM

6. STRUCTURE OF NERVOUS SYSTEM
 The specialised cells that constitute
the functional units of nervous
system are called NEURONS.
NEURONS
 Axon/Nerve fibre
 Cell body/soma
 Dendrites/Receiving process

7. Function of Non neuronal cells(GLIAL CELLS): maintain homeostasis &
provide support and protection to the neurons.
CNS
 Oligodendrocytes
 Astrocytes
 Microglia
 Ependymal Cells
PNS
 Schwann Cells
 Satellite Cells

8. CLASSIFICATION OF NEURONS
Depending upon number of
Poles:
1. Unipolar Neurons
2. Bipolar Neurons
3. Multipolar Neurons
Depending upon length of
Axon:
1.Golgi type I Neurons
2.Golgi type II Neurons

9. CRANIAL NERVES
 These are peripheral nerves that emerge from cranial nerve nuclei of
brainstem & spinal cord.
 They innervate the head & neck.
 Depending on what structures they innervate, peripheral nerves have
following modalities:
i. SPECIAL: Innervating special senses,found only in afferent fibres.
ii. GENERAL: Supplies everything except special senses.
iii. SOMATIC: Skin & Skeletal muscles.
iv. VISCERAL: Supplies internal organs.
Peripheral nerves can be:
a) SENSORY (afferent)
b) MOTOR (efferent)
c) MIXED (both)

10. ORDER OF CRANIAL NERVES
 Cranial nerves are numbered according to their order of exit through skull
fissures.
 They are 12 in number; each named for its function or structure.

11. TRIGEMINAL NERVE
Fifth and the largest cranial nerve.
Mixed cranial nerve.
Dentist nerve.
The name is derived from latin.
TRI=three
3 major branches
GEMINUS=twin
Pair of nerve arising on each
side of the pons

12. EMBRYOLOGY OF THE NERVE
o During development of embryo, pharyngeal arches (6) appear in the 4th & 5th
week.
o The trigeminal ganglia is first visible in week 4,initially developing from neural
crest cells before neural fold fusion, and after fusion receives contribution from
neural tube roof plate.
o This is all derived from the 1st pharangeal arch and hence,this nerve innervates
the structures derived from it.
Each division of trigeminal nerve is associated with the developing facial
process that gives rise to specific area of adult face:
a. Ophthalmic nerve- Frontonasal process
b. Maxillary nerve- Maxillary process
c. Mandibular nerve- Mandibular process

13. ANATOMY OF THE NERVE
ORIGIN
 From 3 sensory nuclei & 1 motor nucleus; extending from midbrain
to the medulla.
 At the level of pons: sensory nuclei merge to form a sensory root.
 The motor nucleus continues to form a motor root.
 In the middle cranial fossa, the sensory root expands into trigeminal
ganglion.

14. NUCLEI OF TRIGEMINAL NERVE
It has got 4 nuclei:
A. MAIN SENSORY NUCLEUS:
Situated : in upper part of Pons, lateral to motor nucleus.
Relays impulses of touch & pressure from skin & mucous membrane of facial region.
B. SPINAL NUCLEUS:
Extends from caudal end of principal sensory nucleus in Pons to L2 segment of spinal
cord.
Relays impulses of pain & temperature of face.

15. D. MOTOR NUCLEUS:
Situated in upper pons medial to principal sensory nucleus.
Innervates muscles of mastication and tensor tympani & tensor palatini.
C. MESENCEPHALIC NUCLEUS:
Situated in midbrain.
1st order sensory nuclei.
Relays impulses of proprioception from : muscles of mastication, facial muscles, eye.

16. TRIGEMINAL GANGLION
 Sensory ganglion of fifth cranial nerve.
 Also known as ‘semilunar’ or ‘gasserian’ ganglion.
 Shape: crescentic or semilunar.
 It is madeup of pseudounipolar nerve cells, with a t-shaped arrangement of
process; one process arises from cell body which then divides into a central
and peripheral process.

17.  2 in number, one innervating each side of face.
 3 divisions of trigeminal nerve emerge from this convexity.
 Lies at the apex of petrous temporal bone on the anterior surface.
 Occupies a special space of duramater, called the ‘Trigeminal’ or ‘Meckel’s
Cave’.

18. ASSOCIATED ROOTS & BRANCHES:
 The central process of ganglion cells form the large sensory root of the
trigeminal nerve, which is attached to pons at its junction with middle cerebellar
peduncle.
 The peripheral process of the ganglion cells form the 3 divisions of trigeminal
nerve.
 The small motor root of trigeminal nerve is attached to the pons superomedial
to sensory root.
 It passes under the ganglion from its medial to lateral side , joins the
mandibular nerve at foramen ovale.

19. DIVISION OF TRIGEMINAL
NERVE
V1:
OPHTHALMIC
(Sensory)
V2: MAXILLARY
(Sensory)
V3:
MANDIBULAR
(Mixed)

20. V1: OPHTHALMIC BRANCH
 Most superior & smallest division.
 About 2.5cm long
 After leaving the trigeminal ganglion, it pierces a layer of duramater, travels in
lateral wall of cavernous sinus and continues through superior orbital fissure.

21. Just before entering the orbit by superior orbital fissure; it divides into:
LACRIMAL
FRONTAL
SUPRA ORBITAL
SUPRA
TROCHLEAR
NASO CILIARY
LONG CILIARY
SHORT CILIARY
INFRATROCHLEAR
ANTERIOR
ETHMOIDAL
EXTERNAL NASAL
INTERNAL NASAL
POSTERIOR
ETHMOIDAL

22. A. LACRIMAL BRANCH:
 Smallest, most lateral & thinnest branch.
 Passes into orbit through lateral compartment
of superior orbital fissure outside the tendinous
ring.
 Connected with zygomaticotemporal branch of
maxillary nerve.
Secretomotor fibres to lacrimal gland.
 Runs in anterior direction with lacrimal artery.
 Enters lacrimal gland, supplying it and
adjoining conjunctiva.
 It then pierces the orbital septum.
 Ends in the upper eyelid.

23. B.FRONTAL BRANCH:
 Largest branch of ophthalmic division.
 Enters the orbit by superior orbital fissure, and runs forward between levator
palpebral superioris & periosteum.
 It further divides into 2 branches:
(i)SUPRA ORBITAL:
• Larger & more laterally placed
• Passes through supra-orbital notch.
• Supplies-skin of forehead, scalp, mucous
memb. of frontal sinus & pericranium.
(ii)SUPRA TROCHLEAR:
• Smaller & more medially placed.
• Curves around supero-medial margin of orbit.
• Supplies-skin of upper eyelid and lower part
of forehead.

24. C. NASOCILIARY BRANCH:
• Intermediate in size between frontal and lacrimal nerve.
• Deeply placed into the orbit.
• Originates from ophthalmic nerve in the anterior part of cavernous sinus.
• Its branches are divided as follows:
#BRANCHESIN ORBIT:
I. Long ciliary nerve: Supplies iris & cornea.
II. Short ciliary nerve: Sensory to eyeball.
III. Infratrochlear nerve: Both eyelids, sides of nose, lacrimal sac.

25. IV. Anterior Ethmoidal nerve: Supplies ant. Ethmoidal & frontal sinus.
In upper part of nasal cavity, it further divides into:
V. Posterior Ethmoidal nerve: Enters the post. Ethmoidal canal & supplies
mucous membrane lining of post. Ethmoidal & sphenoidal sinus.
#BRANCHES IN NASALCAVITY: Supplies mucous memb. of nasal cavity.
#TERMINAL BRANCHES ON FACE: Supply sensory nerves to the skin of medial parts of both
eyelids, lacrimal sac; Also supply skin on the bridge of nose.
INTERNAL NASAL
Medial & septal branches to septal membrane.
Lateral branches which supply nasal conchae & ant. nasal wall.
EXTERNAL NASAL
Supplies the skin on tip & ala of nose.
INTERNAL NASAL
EXTERNAL NASAL

26. Middle Cranial Fossa
Foramen Rotundum
Pterygopalatine
Fossa
Inferior Orbital
Fissure
Infra Orbital
Groove
Infra Orbital
Foramen
V2: MAXILLARY NERVE
 Second & intermediate division of trigeminal nerve.

27. BRANCHES OF MAXILLARY NERVE
A. MIDDLE CRANIAL FOSSA:
Middle meningeal nerve.
B. PTERYGOPALATINE FOSSA:
i. Zygomatic: Zygomaticotemporal
Zygomaticofacial
ii.Ganglionic:
Orbital Palatine Nasal Pharyngeal
iii.Posterior Superior Alveolar (PSA)
C. INFRAORBITAL CANAL:
i. Middle superior alveolar
ii.Anterior superior alveolar
D.ON THE FACE:
i. Inferior Palpebral
ii.Lateral nasal
iii.Superior labial
SENSORY

28. A.MIDDLE CRANIAL FOSSA
i. Middle Meningeal nerve:
• Given off from maxillary nerve directly after its origin from semilunar ganglion
• Supplies the duramater.

29. B. PTERYGOPALATINE FOSSA
i. Zygomatic nerve:
 Arises from pterygopalatine fossa.
 Enters orbit through inferior orbital fissure and then divides into 2 branches:
a. Zygomaticotemporal branch:
• Receives communication from lacrimal.
• Passes through foramen in zygomatic bone and enters temporal fossa.
• It then pierces temporal fascia and gets distributed to the skin of side of
forehead.
b. Zygomaticofacial branch:
• Emerges from the face through foramen in zygomatic bone.
• Perforates the facial surfaces and supplies skin of cheek (prominence of
zygomatic bone).

30. ii. Ganglionic Branches:
• Arise as 2 trunks which join to form single root within pterygopalatine ganglion.
• Gives off various branches that supply 4 areas:
a.Orbital: Supplies periosteum of orbit.
b.Nasal:
Superior Posterior Nasal Nasopalatine
Lateral Medial
Supplies:
-Post. part of roof & septum.
Supplies:
-Superior & middle nasal
conchae
-Lining of post ethmoidal cells
-Posterior part of septum

31. NASOPALATINE BRANCH:
• It is one of the medial branches
distinguished by its greater length
and diagonal course downwards &
forward along the nasal septum.
• Gives off its branches to anterior part of nasal septum & floor of nose.
• Enters the incisive canal & passes into oral cavity through incisive foramen.
• The right and left branches emerge together through this foramen and
provides sensation to the palatal mucosa in region of pre-maxilla (canine
to CI).

32. c. Palatine Branches:
 Distributed to the roof of mouth, soft palate, tonsil & lining memb. Of nasal cavity.
i. Greater Palatine Nerve: Emerges on hard palate by passing through greater palatine
foramen and courses in anterior direction between the osseous hard palate and
mucoperiosteum to supply major part of hard palate and Palatine gingiva.
• Also extends to the premaxillary palatine mucosa.
ii. Middle Palatine Nerve: Emerges through one of the minor Palatine canals and
distributes branches to the uvula, tonsil and soft palate.
iii. Posterior Palatine nerve: Descends through pterygopalatine canal and emerges by a
separate opening behind the greater palatine foramen.
• Supplies soft palate, tonsil and uvula.
d. Pharyngeal Nerve:
 small nerve.
 Passes through pharyngeal canal and is distributed to the mucous membrane of nasal
part of pharynx.

33. iii. Posterior superior alveolar nerve:
• Descends from the main trunk of maxillary division in pterygopalatine fossa, just
before entering inferior orbital canal.
• Through fossa, it reaches the inferior temporal surface of maxilla and enters the
alveolar canals.
• Travels down the posterolateral wall of maxillary sinus ;
providing sensory innervation to the alveoli, PDL and pulpal tissues of maxillary 3rd,
2nd & 1st molar (DB+P roots).
• Also supplies adjoining part of gingiva & cheek along buccal side.
• Applied anatomy: during PSA nerve block, there is risk of hematoma formation.

34. C. INFRAORBITAL CANAL:
 When the maxillary nerve enters the orbit through inferior orbital fissure & lies in
the infraorbital groove, it is called infraorbital nerve.
 It passes through infra orbital canal, where it gives off 2 branches:
i. Middle Superior Alveolar Nerve (MSA):
• Given off from the nerve in the post. part of canal.
• Runs forward and enters the lateral wall of maxillary sinus.
• Provides sensory innervation to max premolars and MB root of max 1st molar and
the periodontal tissues, buccal soft tissues and bone in pre-molar region.

35. ii. Anterior Superior Alveolar Nerve(ASA):
• Given off from the nerve just before its exit from infra orbital foramen.
• Assists in formation of superior dental plexus along with PSA & MSA and gives off
nasal branch to supply mucous memb. of anterior area of lateral wall & floor of
nasal cavity.
Provides pulpal innervation : central & lateral incisors,canine;
periodontal tissues,
buccal bone
mucous memb. of same teeth.

36. D. ON THE FACE:
 Infraorbital nerve emrerges through the infraorbital foramen and
divides into its terminal branches:
i. Inferior Palpebral:
• Supplies lower eyelid & lateral angle of eye.
ii. Lateral Nasal:
• Sensory innervation to the lateral part of nose.
iii. Superior Labial:
• Large & numerous.
• Supply the skin over ant. part of cheek and upper lip including mucous
membrane & labial glands.

37. V3: MANDIBULAR NERVE
 Largest division of trigeminal nerve.
 It is a mixed nerve.
 Formed by union of 2 roots:
Large sensory root descends from semilunar ganglion.
Small motor root emerges from medulla oblongata.
 The motor root passes beneath the ganglion & unites with the sensory root just
after its exit from foramen ovale: to form main trunk.
 Immediately beyond the junction of 2 roots, the nerve sends off a meningeal
branch and nerve to medial pterygoid.
 Trunk remains undivided for 2-3 mm.
 Then divides into 2 trunks: ANTERIOR
POSTERIOR

38. DIVISIONS OF MANDIBULAR NERVE
BRANCHES FROM MAIN TRUNK: (UNDIVIDED)
-Meningeal Branch
-Nerve to medial pterygoid
BRANCHES OF DIVIDED NERVE:
A. ANTERIOR TRUNK:
I. Deep Temporal
II. Lateral Pterygoid
III. Masseteric
IV. Buccal
B. POSTERIOR TRUNK:
I. Auriculotemporal
II. Lingual
III. Inferior Alveolar

39. a. MENINGEAL BRANCH:
 Also called nervous spinosum.
 It re-enters the cranium through foramen spinosum along with middle
meningeal artery to supply the duramater and mastoid air cells.
 It divides into 2 branches:
B. NERVE TO MEDIAL PTERYGOID:
 Supplies medial pterygoid muscles.
 Also gives off smaller branches to: tensor veli palatini & tensor tympani.
ANTERIOR
-Communicates with meningeal
branch of maxillary nerve
POSTERIOR
-Supplies mucous lining of mastoid
cells.
UNDIVIDED BRANCHES:

40. ANTERIOR BRANCHES
 Significantly smaller than posterior division.
 Receives sensory & motor fibres: supply muscles of mastication, skin;
mucous membrane of cheek & buccal gingiva ; lower molars.
Passes downwards & forwards :
I. Branch to lateral Pterygoid-motor supply
II. Branch to masseter muscle-Masseteric nerve
III. Branch to deep temporal-Temporalis muscle
IV. Buccal Nerve

41. iv. BuccalNerve:
 Also called Long buccal nerve.
 Passes downwards anteriorly & laterally between the two heads of external
pterygoid muscles.
 It emerges under the anterior border of masseter muscle at the level of occlusal
plane of mandibular 3rd & 2nd molar.
 Crosses infront of ramus and enters the cheek through buccinator muscle.
 It provides sensory innervation to:
Skin over anterior part of buccinator
Buccal gingiva of mand. Molars
Muccobuccal fold in that region.

42. POSTERIOR BRANCHES
 It is mainly sensory but also carries motor fibres.
 Descends downwards & medially to lateral pterygoid and branches into:
I. AURICULOTEMPORALNERVE:
 Parotid branches: secretomotor, vasomotor
 Articular branches: to the TMJ
 Auricular branches: to the skin of helix and tragus of the ear
 Meatal branches: skin over the meatus and the tympanic membrane
 Terminal branches: scalp over the temporal region

43. II. LINGUAL NERVE:
o Second branch of the posterior division of the mandibular nerve.
o Runs between tensor veli palatini & lateral pterygoid where it is joined by chorda
tympani branch of facial nerve from here.
o It descends to rest between the ramus and the medial pterygoid muscle in the
pterygomandibular space.
o Runs anterior and medial to the inferior alveolar nerve, whose path it parallels.
o Continues to reach the side of the base of the tongue slightly below and
behind the mandibular third molar where it lies just below the mucous
membrane in the lateral lingual sulcus.
o Proceeds anteriorly across the muscles of the tongue.
o Medial and deep to submandibular & sublingual gland, it breaks up into its
terminal branches.

44. SUPPLY: mucosa of floor of mouth, lingual gingiva, mucosa of anterior 2/3rd of
tongue, carries post ganglionic fibres from submandibular ganglion to sublingual
& ant. Lingual glands.
APPLIED ANATOMY: Greater risk during surgical removal of impacted third molar &
submandibular salivary gland.

45. III. INFERIOR ALVEOLAR NERVE
 Largest branch of mandibular division.
 Descends medial to the lateral pterygoid muscle and lateroposterior to the
lingual nerve.
 Passes between the sphenomandibular ligament and the medial surface of the
mandibular ramus to enter the mandibular canal via mandibular foramen.
 The nerve travels anteriorly in the mandibular canal till it reaches the mental
foramen.
Continues forward in the bony
canal & gives off various branches
(INCISIVE NERVE)
Exits the canal between & just
below the premolar and divides
into various branches
(MENTAL NERVE)

46. a. MYLOHYOIDNERVE:
• branches just before entering the mandibular foramen.
• Supplies the mylohyoid muscle and anterior belly of digastric.
b. DENTALBRANCHES:
• supply molar & pre-molar teeth.
• above the alveolar nerve, they form an inferior dental plexus.
c. INCISIVEBRANCH:
• continued onward within the bone
• supplies canine & incisor teeth and associated labial gingiva.
d. MENTALNERVE:
• Emerges at mental foramen & divides into various branches to supply:
• skin of chin
• skin of mucous membrane of lower lip
• buccal mucosa from 2nd premolar to midline.

47. APPLIED ANATOMY OF TRIGEMINAL
NERVE
• NERVE BLOCKS FOR LOCAL ANESTHESIA
• TRIGEMINAL NEURALGIA
• HERPES ZOSTER OPHTHALMICUS
• INFECTIONS
• DENTAL IMPLANTS

48. NERVE BLOCKS FOR LA
 Various anatomical landmarks are important to know with proper techniques for
local anesthesia of nerve to prevent complications.

49. TRIGEMINAL NEURALGIA
 It is also called as or
 The term Tic Douloreux is applied only when the patient suffers from spasmodic
contractions of the facial muscles.
 Etiology:
1. Dental pathosis
2. Excessive traction
3. Allergic
4. Ischemia
5. Mechanical factors like pressures due to aneurysms
6. Secondary lesions like carcinoma of the maxillary antrum, nasopharyngeal
carcinoma, tumours of peripheral nerve root and multiple sclerosis.
Tic Douloreux, trifacial neuralgia Fothergill’s disease.

50. CLINICAL FEATURES:
 Age and sex distribution –
middle age and old age
women.
 Site –more common on right side and
the lower portion of the face.
 Nature of pain –paroxysmal, lasting only a few seconds - minutes and is usually of
extreme intensity; resembling ‘knife-like stabs’ ‘lightening, ‘electric shock,
'stabbing 'or ‘lancinating’ type of pain.
 Location of pain – confined to the trigeminal zone, nearly always unilateral and if
bilateral. The mandibular and maxillary divisions are more commonly involved
than the ophthalmic.
 Aggravating factors –touch ,a draft of air, any movement of the face as in talking,
chewing, yawning or swallowing may evoke a lancinating attack.

51.  Trigger zones-they precipitate an attack when touched, are common on the
vermilion border of the lips, the ala of the nose ,the cheeks and around the eyes.
 Frozen or mask like appearance-in extreme cases,
patient will have motionless face.

52. DIAGNOSIS:
 Clinical examination with typical history of pain.
 Diagnostic LA blocks
 CT scan & MRI

53. TREATMENT:

54. HERPES ZOSTER OPHTHALMICUS
 Caused by Varicella Zoster.
 Predilection for nasociliary branch of ophthalmic division of trigeminal nerve.
 CLINICAL FEATURES :
o rash ,vesicles, pustules
o ocular lesion: eyelid-periorbital pain
o oedema
o hyperaesthesia
o conjunctivitis
o sclerosis
o corneal scarring
o glaucoma
 Usually unilateral distribution of the lesion.

55. TREATMENT:

56. INFECTIONS
 Bacteria & viruses can cause neural damage resulting in peripheral neuropathy.
 Most notable virus: herpes zoster causing post herpetic neuralgia and
ramsay hunt syndrome ii(herpes zoster oticus).
 After initial infection ,the varicella zoster establishes latency in spinal and cranial
nerve ganglion.
 After reactivation and replication the viruses spread from the sensory nerve fibres
in the ganglion to the involved dermatomes.
 Other than dermatologic manifestations there are a multitude of neurologic
manifestations ranging from neuropathic pain to paraesthesia.
 Pain persists beyond 3 months : post herpetic neuralgia.
 Pain type: stabbing, burning, gnawing and shooting type.
 Cause of pain: destruction of primary afferent c fibres

57. DENTAL IMPLANTS
 Posterior Superior Alveolar nerve & Infra-orbital nerve in maxilla.
 Mandibular nerve: mechanical trauma due to intrusion of implant into
mandibular canal.

58. CONCLUSION
 Trigeminal nerve is a mixed nerve and supplies mainly head & neck
region; thus thorough knowledge about its course and distribution is
necessary to perform dental treatments/surgeries and avoid its
complications.
 Nerve blocks to carry out various dental procedures involve various
branches of trigeminal nerve, which is important from dentist point of
view to prevent its complications.

59. REFERENCES
• B.D. Chaurasia’s Human Anatomy, Vol.3, 6th edition
• Essential of Medical Physiology, K. Sembulingam, 6th edition
• Handbook of Local Anesthesia, Stanley F. Malamed, 6th edition
• Human Embryology, Inderbir Singh, 8th edition
• Shafer’s textbook of Oral Pathology
• Textbook of Oral & Maxillofacial Surgery, S.M. Balaji, 3rd edition
• Burkett’s Oral Medicine,11th edition
• Gray’s Anatomy for students, 2nd edition
• Cranial Nerves: Functional Anatomy , Stanley Monkhouse