this presentation consist of introduction to types of nerves, structure of nerve and cranial nerves. there is a detail description about, origin , course of the trigeminal nerve and its branches and the structures supplying the nerve. it also contains applied anatomy of the nerve and its importance of the nerve in oral and maxillofacial surgeries. a detail description about the examination of the trigeminal nerve is also mentioned in the presentation. hoping that it would be useful to the students and people seeking for knowledge about the trigeminal nerve.

1. DEPARTMENT OF ORAL AND MAXILLOFACIAL
SURGERY

2. CONTENTS
1. Introduction
2. Embryology
3. Course of the nerve
4. Branches of the nerve
5. Impulse and pain pathway
6. Applied anatomy
7. Conclusion
8. References

3. INTRODUCTION
•Human nervous system is the
most complex product of
biological evolution which
constitutes of nerve.
• nerves are formed by group
of neurons.

4. •Neurons are specialized cells that constitute the functional unit of the nerve.
• Each neuron consist of a :
1. Cell body (perikaryon)
2. Axon
3. Dendrites

5. •The nervous system consist
of three basic functional
types of neurons:
Sensory neuron
Motor neuron
Interneuron

6. Nervous system
Central nervous system
brain Spinal cord
Peripheral nervous system
Spinal nerves Cranial neres

7. • spinal nerves: these nerves are by
which the CNS receives information
from and controls the activity of the
spinal cord and pass through
intervertebral foramen in the
vertebral column.
•There are 31 pairs of spinal nerves
8 cervical 12 thoracic 5 lumbar
5 sacral 1 coccygeal

8. •Cranial nerves: by which the brain receives information
from and controls the activities of the head and neck and to
lesser extend the thoracic and abdomen viscera

9. TRIGEMINAL NERVE:
• It is the fifth cranial nerve
• It is the largest nerve
• General somatic afferent fibers convey both:
exteroceptive proprioceptive
impulse impulse
1. mucous membrane 1. teeth
2. periodontium
3. hard palate
4. TMJ receptors

10. Nucleus of trigeminal nerve are:
General somatic afferent brachial efferent nucleus
1. superior sensory nucleus 1. motor nucleus
2. spinal nucleus
3. mesenchephalic nucleus

11. Trigeminal nerve has three branches:
1. Ophthalmic division: it carries sensory
supply from the structures derived from
frontal process. It is purely sensory
2. Maxillary division : carries fibers from
structures derived from maxillary process
It is purely sensory
3. Mandibular division: it carries sensory
fibers from mandibular process and motor
fibers to muscles of mastication

12. EMBRYOLOGY OF THE NERVE
•Nervous system develops from ectoderm around the 3rd week of
development
•It overlies notochord
•At the time when neural plate is formed some cells at the junction of the
neural plate and rest of the ectoderm becomes specialized to form the
primordial of the nuclear crest
•From this neural crest several important structures are derived

13. •The brain and the cranial sensation innervations have their origin in
prediffrentiation period from 3 ectodermal sources:
dorsal neural crest
neural crest
surface epithelium placode

14. INTRA CRANIAL COURSE OF TRIGEMINAL NERVE

15. •SENSORY ROOT:
the sensation of pain, temperature, touch, pressure from the skin of the
face and mucous membrane travels along the axon whose cell bodies lie
in the trigeminal ganglion .
TRIGEMINAL GANGLION:
it is crecentric in shape
located at the upper surface of the apex of petrous temporal bone
in the middle cranial fossa in a cave called Meckle's cartilage
it is developed from neural crest
the ganglion with its unipolar neurons forms central and peripheral
processes

17. •The periphery process forms the ophthalmic , maxillary and
mandibular division
•The central process forms the sensory root of the nerve.
•It gives off ascending and descending fibers
•The ascending fibers terminates in the upper sensory nucleus and
the descending fibers terminates in the spinal nucleus
•Few fibers from the mandibular nerve enters the mesenchephalic
nucleus

19. TRIGEMINAL NEUCLEUS:
Main sensory nucleus:
• It lies in upper Pons laterally to motor
nucleus .
• It continues below with spinal nucleus.
• This gives rise to the dorsal
trigeminothalamic tract , these sensory fibers
ascends upward , then crosses to
opposite side accompanying the
medial lemniscus thalamus.
• These fibers carry touch and temperature
sensation.

20. Spinal nucleus:
• Continues superiorly with the
sensory nucleus in the Pons and extends
inferiorly through out the medulla oblongata,
into upper part of the spinal cord
as far as the second cervical segment.
• It conveys pain and temperature sensation

21. Mesencephalic nucleus:
• It is composed of column of
unipolar nerve cells situated in the
Lateral part of the grey matter
around the cerebral aqueduct in
the mid brain.
• It extends inferiorly into the
Pons as far as the main sensory nucleus.
• Proprioceptic impulse from
• muscles of mastication and teeth.

22. MOTOR ROOT:
The efferent fibers are passed from cortico nuclear fibers from
both cerebral hemisphere , from reticular formation of the red nucleus,
the tectum and the medial longitudinal fasciculus to the motor nucleus.
Motor nucleus is located in upper Pons medial to main sensory
nucleus.
From the motor nucleus fibers travel along the medial side of
semi lunar ganglion, passes through foramen ovale through which it
joins the sensory root.

24. BRANCHES OF TRIGEMINAL NERVE
OPHTHALMIC NERVE
Nasociliary nerve frontal nerve lacrimal nerve
Orbit nasal terminal supraorbital supratrochlear
Branch branches branches nerve nerve

25. The nerve leaves the anterior medial
part of the ganglion and exist through
Superior orbital fissure
In middle cranial fossa, the nervus
tentorii branches are given to supply
the Dura
The nerve is divided into 3 branches:
• lacrimal nerve
• frontal nerve
• nasociliary nerve

26. •LACRIMAL NERVE
•It supplies sensory fibers to the gland and adjacent conjunctiva.
• In the orbit, postganglionic secretory fibers from the sphenopalatine
ganglion meet and travel along with the lacrimal gland.

27. FRONTAL NERVE:
•It is divided into :
1. supraorbital
2. supratrochlear.
• Supraorbital: supplies upper eyelid
forehead,
anterior scalp region.
•Supratrochlear: supplies skin of
upper eyelid.

28. NASOCILIARY NERVE:
• Branches are divided into those
1. Arising in orbit
2. Arising in nasal cavity
3. Terminal branches

29. Branches arising from orbit
1.Short ciliary nerve:
2.Long ciliary nerve: they distribute to iris and cornea
these nerve contain post ganglion fibers, from the superior
cervical sympathetic ganglion.

30. 3. Posterior ethmoid nerve: distributes to mucous membrane lining the
posterior ethmoidal cells and the sphenoid sinus

31. •4. Anterior ethmoid nerve: distributes to mucous membrane lining the
anterior ethmoidal cells and frontal sinus.
•Branches:
internal nasal. br
external nasal. br

32. Branches arising from nasal cavity:
Supplies the mucous membrane lining the nasal cavity.
Terminal branches:
These terminal branches course below the trochlear nerve to
supply sensory fibers to the skin of the medial part of both eyelids,
lacrimal sac and lacrimal cruncle.

33. •GANGLION ASSOCIATED WITH OPHTHALMIC DIVISION:
Ciliary ganglion: it lies in the posterior part of the orbital cavity to the
lateral side of the optic nerve medial to the rectus lateralis muscle.
The ciliary ganglion has three roots:
1. motor root: ( preganglioin, parasympathetic) these motor fibers
arises from the nucleus of EDINGER WESTPHAL.
the oculomotor nucleus lies in the gray matter in Mesencephalic. The
axons of the autonomic nucleus with the fibers of the oculomotor
nerve to the ciliary ganglion.
They are the visceral efferent bundle that carries preganglioin fibers to
the ciliary ganglion

34. •2. sensory root (postganglionic, sympathetic): the sensory fibers of the
ciliary ganglion are derived from the nasociliary nerve of trigeminal
nerve. This root also carries many postganglionic fiber from cell bodies
of the superior cervical sympathetic ganglion. They join nasociliary
nerve. They pass through the ganglion without synapses to innervate
the radial fibers of the dilator pupillae muscle in the iris

35. 3. sympathetic root: these fibers may come from the sensory root of
the nasociliary nerve or directly from the internal carotid plexus. Short
ciliary nerves emerges from the anterior border of the ciliary ganglion.
And continue on the posterior surface of the eye ball.
•Fibers of the short ciliary nerves contains sensory, parasympathetic
and sympathetic fibers. They run in the inner surface of the sclera
towards the iris. The post ganglion fibers to the parasympathetic
group innervates the circular or sphincter , muscles fibers of iris, which
cause the pupil to constrict. They also innervates the ciliary muscle,
which change the convexity of the crystalline lens. Post ganglion
fibers of sym[pathetic group pass to the radial fibers of the dilator
papillae muscles of iris

36. MAXILLARY NERVE
It transmits sensory fibers from the skin of face between the lower
eyelid, the mouth, the nasal cavity and the sinus.

37. Branches of maxillary nerve:
in the cranium in pterygopalatine fossa in infaorbital canal on face
Middle meningeal
mid.sup.alv. Nerve ant.sup.alv.nerve
Ganglion branches zygomatic post.aup.alv.nerve
inferior palpebral ext.nasal superior
zygomaticotemporal zyomaticofacial labial

38. 1. Branches with in the cranium:
1. middle meningeal nerve:
immediately after separating from the
trigeminal ganglion, the maxillary nerve gives off
middle meningeal branches.
it passes with the middle meningeal artery.
it fibers supply Dura with sensory fibers.

39. •2. branches in pterygopalatine fossa:
1. pterygopalatine nerve
2. zygomatic nerve
3. posterior superior alveolar
1. pterygopalatine nerve:
1.orbital branches:
supplies periosteum of the orbit
mucous membrane of part of
posterior ethmoidal sinus

40. 2. nasal branches:
1. nasopalatine nerve: 2. posterior superior lateral nasal
nerve
3. Medial or septal branches

41. 3. Palatine branches:
1. greater palatine:
supplies :major part of the hard palate
the palatine gingiva
premaxillary palatine mucosa
floor of the nose and maxillary sinus
2. middle palatine
mucous membrane of the soft palate
3. posterior palatine:
these fibers goes to tonsilar area to supply
tonsil

42. 2. Zygomatic nerve:
it is divided into:
Zygomaticotemporal zyomaticofacial

43. •3. posterior superior alveolar nerve:
descends from the main trunk of the maxillary nerve in the pterygopalatine
fossa.
An internal branch of the posterior superior alveolar nerve goes with a branch
of the internal maxillary artery through the posterior superior alveolar canal.
Opens on the posterior surface of the maxilla.
It supplies posteriolateral wall of
the maxillary sinus and
the molars and their gingiva

44. •3. branches in the infraorbital canal:
1. middle superior alveolar nerve:
2. anterior superior alveolar nerve:

45. •The innervations of roots of all the teeth bones and periodontal
structures are derives from terminal branches of large nerves.
• These nerves makes network called dental plexus
SUPERIOR DENTAL PLEXUS
dental nerve inter dental branches inter radicular

46. •TREMINAL BRANCHES ON FACE:
•Inferior palpebral
•External or lateral nasal branches
•Superior labial branches

47. MANDIBULAR DIVISION:
It supplies sensory fibers to: It supplies motor fibers to:
Oral cavity Masseter
Tongue Lateral pterygoid muscle
Chin Medial pterygoid muscle
Cheek Temporal muscle
Parotid gland Anterior belly of digastric muscle
Tympanic membrane Mylohyoid
Temporal region Tensor veli palatine
Meninges Tensor tympani

48. BRANCHES OF MANDIBULAR NERVE
Main trunk divided nerve
Nervus spinosus nerve to medial anterior division posterior division
pterygoid muscle nerves to 1. auriculotemporal
1. lateral pterygoid 2. lingual nerve
2. masseter 3. inferior alveolar. N
3. temporal muscle
4. buccal nerve

50. 1.Nervus spinosus:
It supplies: cartilaginous part of Eustachian tube
middle cranial fossa Dura matter in posterior half
mastoid cells
2. Nerve to the medial pterygoid:
It innervates the medial pterygoid
It has branches that passes close to otic ganglion and
supplies tensor veli palatine
Tensor tympani

51. •Branches of anterior division;
branches to lateral pterygoid
branch to masseter
branches to temporal:
anterior deep temporal
posterior deep temporal
long buccal nerve

52. 1. Branches to lateral pterygoid muscle: The nerve passes medial to
the lateral pterygoid muscle to supply the motor nerves to the
muscle
2. Branches to masseter muscle: The nerve passes above the lateral
pterygoid muscle to transverse the mandible notch and enters the
deep side of the muscle
3. Nerve to the temporal muscle:
1. Anterior deep temporal muscle: Passes upward and
crosses the infratemporal crest of the sphenoid bone. It ends in the
deep part of the anterior portion of the temporal muscle.
2. Posterior deep temporal muscle : The nerve passes deep
part of the temporal muscle.

53. 4. Buccal nerve: The nerve passes in between the two heads of the
lateral pterygoid.
It passes downward , deep to the temporal muscle at the lower end of
the lateral pterygoid muscle.
It emerges under the anterior border of masseter muscle continues
anterior lateral direction
At the level of the occlusal plane of mandibular teeth it crosses in front
of anterior border of the rams and enters in to the cheek through
buccinators
It gives of branches to skin over the soft cheek
After piercing the buccinators, it supplies the mucous membrane
adherent to the deep surface of the muscle, passes into the

54. Retro molar triangle and ends by supplying sensory innervations to the
buccal gingiva of the mandibular molars and the adjoining
muccobucal fold

55. •Branches of posterior division:
1. auriculotemporal nerve
2. lingual nerve
3. inferior alveolar nerve

56. auriculotemporal branch:
two roots embraces middle meningeal artery and join to form 1 trunk
between the two heads of the lateral pterygoid
passes between the spenomandiular ligament and the condylar head
Transverse the deep part of parotid gland
Crosses the posterior root of the zygomatic arch
Passes with the auriculotemporal artery
Upward and divides into numerous branches

57. •Communicating branches of the auriculotemporal nerve:
postganglionic parasympathetic secretory fibers
postganglionic sympathetic nerve
communicating branches of facial nerve
•Branches of auriculotemporal nerve:
1. parotid branch
2. articular branch
3. auricular branch
4. metal branch
5. terminal branch

58. •Lingual nerve:

59. •Communicating branches of lingual nerve:
it is joined by corda tympani, a branch of facial nerve about the
base of the skull . These fibers convey secretory fibers from the facial
nerve
The parasympathetic secretory fibers control submandibular ganglion,
where they synapse.

60. Inferior alveolar nerve:

61. •Branches of inferior alveolar nerve :
mental nerve : leaves through mental foramen, and supplies
to mucous membrane lining of the lower lip
incisive nerve: continues anteriorly in the body of the
mandible to form incisive plexus.

62. • mylohyoid nerve: it is motor to mylohyoid muscle and anterior belly
of digastric muscle

63. APPLIED ANATOMY

64. EXAMINATION OF TRIGEMINAL NERVE:
Purpose:
1. To determine, if any of the modalities of sensation are
impaired.
2. To decide from this whether the lesion lies in one of the
peripheral branch or in the trigeminal ganglion or the sensory root or
in the brain stem
3. To determine the motor lesion is unilateral or bilateral.

65. •Methods of examination:
here the pain and light are main modalities.
6 areas on the face are tested
1. forehead
2. side of the nose
3. malar region
4. upper lip
5. chin
6. anterior part of the tongue

66. •Abnormalities:
1. Total loss of sensation :
over whole distribution of the nerve:
tumor eroding at the base of the skull
large neurofibromatosis lesions
epidermoids
basal injuries
over one or more of the main division:
herpes zoster
acoustic neuroma

67. 2. Only touch is lost: pointic lesion effecting the principal sensory
nucleus
eg: Pontine tumor
Brain stem displacement by large tumor
3. Pain and temperature are lost:
Syrinobulbia
Foramen magnum tumor
Bulbar vascular accidents
Thrombosis of the posterior inferior cerebellar artery

68. 4. Hyperesthesia:
Vascular lesion and herpes
5. Onion skin type of sensory loss:
In nuclear lesion of trigeminal nerve, sensory loss can be in
concentric pattern
This onion skin pattern is useful to understand the pattern of sensory
loss in intrinsic brainstem and spinal cord lesion like syrinx and
vertebrobasilar stroke

69. EXAMINATION OF THE MOTOR NERVE:
Motor function of the trigeminal nerve is tested by evaluating the strength
of masseter muscle contraction. The patient is asked to clench the teeth
together while the clinician feels for equal contraction of the right and left
masseter muscles. This is also done for the temporalis muscles.

70. •When the inferior lateral pterygoid contracts, the mandible is protruded
and/or the mouth is opened. Functional manipulation is best accomplished
by having the patient make a protrusive movement. The most effective
manipulation, therefore, is to have the patient protrude against resistance
provided by the examiner

71. Trigeminal reflexes:
1. corneal reflex: Afferent by trigeminal nerve
Efferent by facial nerve
When the opposite eye doesn't blink, a contra lateral facial nerve palsy may
be the cause
When the untested eye only blinks then the facial nerve palsy is ipsilateral

72. 2. Jaw jerks: Afferent by: mandibular
Efferent by: nerve
Abnormal : Ehe jaw jerks are exaggerated and
the pathologically brisk with lesions
effecting motor nucleus

73. 3. Occulocardiac reflex:
It is the sudden physiology response due to the pressure effect or
stretching of the trigeminal nerve.
It is a triad of bradycardia, bradypne, gastric motility changes due to
efferent activation of the vagal nerve

74. TRIGEMINAL NEURALGIA :
•Neuralgia is the pain in the distribution of nerve or nerves
Cause: Arachnoids thickening or Dural contraction
Meningiomas, vascular compression
Demyelization of nerve fiber leads
Multiple sclerosis
Tumor
Location: occurs in two zones: mouth-ear zone
nose-orbit zone
Quality of pain: feels like electrical or red hot needle or machine gun
firing re hot bullets

75. •Triggering of pain:
mouth-ear zone: triggered by motor activities chewing, smiling,
yawning.
nose-orbit zone: provoked by cutaneous trigger.

76. Management:
1. Pharmacological treatment :
1. Anticonvulsants: carbamazepine: 200mg TID
phenytoin : 300mg QID
gabapentine: 1200-3600mg/day
2. Tricyclin antidepressants: anticholinergic effects
sedative effects

77. •2. surgical management:
•
Microvascular decompression Sensory rhizotomy
Radiofrequency rhizotom

78. Balloon Compression Rhizotomy Percutaneous Glycerol Rhizotomy
Radiofrequency Rhizotomy

79. TRIGEMINAL NEUROPATHY:
Neuropathy pain is pain arising as a direct consequence of any lesion
or disease affecting the stomato sensory system.
Painful traumatic neuropathy:
this may occur following major craniofacial or oral trauma.
this has been termed as phantom tooth pain,, atypical odontalgia
or atypical facial pain
neural damages can be as: peripheral neuropathy
ganglionopathy
radiculopathy

80. •Causes:
macro trauma
implants: direct injury
persistent pain associate with injury to small nerves.
proximity between implant and large nerve trunk
mandibular third molar extraction.
Features:
pain – unilateral
moderate to sever – shooting / burning type
sensory dysfunction
•Treatment :
antidepressant + anticonvulsant

81. HERPES ZOSTER OPHTHALMICUS:
Causative agent is: varicella zoster virus
It is recognized as localized vesicular eruption that is limited
to the dermatomes of the sensory spinal or cranial nerves.
Herpes zoster ophthalmicus is the involvement of the ophthalmic
division ( frontal branch).
Involvement of nasociliary nerve may produce characteristic vesicles
at the tip of the nose known as Hutchinson's signs

82. The effected dermatomes shows signs of :
hyperesthesia
Pain
Burning sensation
Itching with associated edema
Erythema
Macular rash

83. Treatment:
1.acyclovir 200mg for every 4th hour for 5 days
2. vidarabine IV
3. ocular treatment

84. •TUMORS OF THE NERVE
TRIGEMINAL SCHWANNOMA:
this is a peripheral intracranial nerve sheath tumor that developed at
the base of the skull and originates from the Schwann cells
It is a benign tumor
Symptoms include: facial pain and numbness
headache or hearing issues
Treatment includes : complete microsurgical removal of the lesion

85. •SUPERIOR ORBITAL FISSURE SYNDROME:
a group of neurological deficit expressed by altered functions
of the nerve passing through the superior orbital fissure due to nerves
passing through the superior orbital fissure due to dislocation of bony
fragment or comminuted fracture in the region of superior orbital
fracture
It is also caused by inflammation and tumor
Symptoms: vision loss
periorbital pain
diplopia
anesthesia
lacrimal hyposecretions

86. CONCLUSION:
trigeminal of nerve is the most important nerve pertaining to head,
To know the course and branches of the nerve is at most important
from surgeons point of view as in evident surgical procedures may
lead to nerve damage followed by impaired function of facial
structures.

87. •REFERENCES: