DR.CHAITHRASHREE

3. CONTENTS
• Introduction
• Terminologies
• Neuroanatomy
• Development of nervous system
• Structure of nerve
Basic Functions of the Nervous
System
• Classification of neurons
• Functional components

4. CONTENTS
• Various types of fibers in the
nervous system
• Human nervous system:
Central nervous system
Peripheral nervous system
• Cranial nerves
Ⅰ Olfactory nerve
Ⅱ Optic nerve
Ⅲ Occulomotor nerve

5. CONTENTS
• Cranial nerves
Ⅳ Trochees nerve
Ⅴ Trigeminal nerve
Ⅵ Abducent nerve
Ⅶ Facial nerve
Ⅷ Vestibulocochlear nerve
Ⅸ Glossopharyngeal nerve
Ⅹ Vagus nerve
Ⅺ Accessory nerve
Ⅻ Hypoglossal nerve

6. CONTENTS
• Cervical plexus
• Conclusion
• References

8. • A nerve impulse is the way nerve cells (neurons) communicate with
one another.
• Master controller and communicating system in the body
• Every thought, action and emotion reflects its activity.
• Its signalling and responding abilities are highly specific and rapid.
INTRODUCTION TO NERVOUS SYSTEM

9.  Nervous tissue has presented
extraordinary challenges to
science
In the human brain there are
approximately
10 billion neurons
The most significant specialized
features of nerve cells are their
axons, dendrites and synapses
Nerve cell processes are quite
thin, often less than a micron
(1µm) in diameter

10. EMBRYOLOGY OF NERVOUS SYSTEM
• Nervous system first appears
about 18 days after conception,
with the genesis of the neural
plate.
Neural plate is divided into neural
crest cells and neural tube
Neural crest cells form : PNS & ANS
Neural tube forms : CNS

12. TERMINOLOGIES
• NUCLEUS: Applies to an
aggregate of nerve cell bodies
• GANGLION: is a group of nerve
cell bodies situated outside
the brain and spinal cord.
 ex: a) sensory ganglia of cranial
nerves
 semilunar , geniculate
 b) parasympathetic ganglia
ciliary, submandibular

13. • TRACT: defined as a group of
nerve cell processes within the
CNS.
• NERVE: is a bundle of neuronal
processes outside the CNS.
Sensory,
Motor,
Mixed.
• PLEXUS: site of intermingling
and regrouping of peripheral
nerve fibers deriving from
diverse origins

14. NEUROANATOMY
• Neuron (nerve cell)–
• It is basic structural and
functional unit of the nervous
system.

15. Structure of Nerve
• Nerve cell body(soma)-
5-7 dendrites extend outward
from the cell body.
Propagated action potentials are
generated
• Axon
Originates from thickened area of
cell body
Transmits propagated impulses to
nerve endings
• Nerve endings
Action potentials cause the release
of synaptic transmitters.

16. Nerve impulses:
• Nerve impulses are mostly electrical signals along the dendrites to
produce a nerve impulse or action potential
• The action potential is the result of ions moving in and out of the cell.
• Impulses are transmitted along chains of neurons, but there is no
direct contact between neurons. The point at which two neurons meet
(but don’t touch) is called a synapse .
• A gap, or synaptic cleft, separates the afferent process (dendrite) of
the receptor neuron from the efferent process (axon) of the
transmitter neuron. Chemical messengers, called neurotransmitters ,
carry the signal across the synapse from axon to dendrite.

17. Conduction of Action potential
 Higher vertebrates have specialized cells called Schwann cells, in the peripheral
nervous system, and oligodendrocytes, in the central nervous system, which
wrap concentric layers of fatty membranes, called myelin , tightly around the
axon.
 The sections of myelin are discontinuous, so that periodically along the length of
the axon there are regions not covered by myelin sheaths, called the Nodes of
Ranvier .
 The tight wrapping of myelin prevents any ionic exchange or spread of electric
current, therefore the action potential can only occur at the nodes.

18.  The nerve impulse or action
potential will “jump” from
node to node greatly
increasing the speed of
nerve transmission
 This node to node
transmission , called
saltatory conduction , can
produce transmission
speeds of up to 200 meters
per second.

19. • Nerve is a bundle of axons
• Endoneurium-
 collagenous tissue layer
surrounding individual axons
• Perineurium -
 strong connective tissue
surrounds each fascicle .
• Epineurium-
loose connective tissue layer,
surrounds fascicles and protects
against external trauma

20. Basic Functions of the Nervous System
• Sensation-
Events or changes occurring
inside and outside the body. Such
changes are known as STIMULI
and the cells that monitor them
are RECEPTORS.
• Integration-
The parallel processing and
interpretation of sensory
information to determine the
appropriate response.
• Reaction-
 Motor output.
 The activation of muscles or
glands (typically via the release of
neurotransmitters (NTs))

21. Classification of neurons
Based on
number of
neurites
Based on the action
Based on functional
components
unipolar
bipolar
multipolar
motorsensory
Somatic
Efferent
Afferent
Special
General
Visceral
Type 1 Type 3Type 2

23. Divisions of Nervous System

25. CENTRAL NERVOUS SYSTEM
• It includes brain and spinal
cord.
• It is formed by neurons and
supporting cells called
neuroglia.

26. CENTRAL NERVOUS SYSTEM
• The brain
Receives sensory input from
the spinal cord as well as
from its own nerves
(e.g., Cranial nerves )
Devotes most of its volume
(and computational power)
to processing its various
sensory inputs.

27. CENTRAL NERVOUS SYSTEM
• Spinal Cord Conducts
 Sensory information from
the peripheral nervous system (both
somatic and autonomic ) to the brain
motor information from the brain to
our various effectors

28. PERIPHERAL NERVOUS SYSTEM
CRANIAL NERVES
12 pair
Cranial nerves pass through
foramina of skull
SPINAL NERVES
31 PAIRS
Spinal nerves leave through inter
vertebral foramina

29. Autonomic Nervous System-
• Sympathetic Nervous system-
The sympathetic nervous
system unconsciously
enables us to be excited.
Consumes energy
Stress — as in the flight-
or-fight response.
• Parasympathetic Nervous
System –
The parasympathetic
nervous system
unconsciously allow us to
rest.
Save energy.
Rest and Digest
Phenomenon

31. SOMATIC NERVOUS SYSTEM
• Consists of nerves connected
to sensory receptors and
skeletal muscles

32. TRAUMATIC LESIONS OF PERIPHERAL
NERVES
SEDDON 1944 described 3 clinical types of nerve injury
• NEUROPRAXIA
It’s a transient nerve block, paralysis is incomplete
Recovery is rapid and complete

34. • AXONOTMESIS
Is a nerve lesion in which axons are damaged but the
surrounding connective tissue sheath remains intact…
 degeneration occurs peripherally
Normal anatomical relationship maintained
 e g..crush injuries,traction and compression
• NEUROTMESIS
 Is the term applied to complete section of nerve trunk
 Wasting and flaccid paralysis

35. Cranial Nerves
• Twelve pairs of nerves
that Originate from the
nervous tissue of the
brain

36. Cranial Nerves
• Ⅰ Olfactory nerve
• Ⅱ Optic nerve
• Ⅲ Occulomotor nerve
• Ⅳ Trochlear nerve
• Ⅴ Trigeminal nerve
• Ⅵ Abducent nerve
• Ⅶ Facial nerve
• Ⅷ Vestibulocochlear nerve
• Ⅸ Glossopharyngeal nerve
• Ⅹ Vagus nerve
• Ⅺ Accessory nerve
• Ⅻ Hypoglossal nerve

37. Cranial Nerves
• Sensory cranial nerves: contain only afferent (sensory) fibers
Ⅰ Olfactory nerve
Ⅱ Optic nerve
Ⅷ Vestibulocochlear nerve
• Motor cranial nerves: contain only efferent (motor) fibers
Ⅲ Oculomotor nerve
Ⅳ Trochlear nerve
Ⅵ Abducent nerve
Ⅺ Accessory nerve
Ⅻ Hypoglossal nerve
• Mixed nerves: contain both sensory and motor fibers---
Ⅴ Trigeminal nerve,
Ⅶ Facial nerve,
Ⅸ Glossopharyngeal nerve
Ⅹ Vagus nerve

38. Cranial Nerve I-
• OLFACTORY NERVE
Component : Sensory
Function : Smell
Origin: Olfactory receptor nerve
cells
Opening to the Skull: Openings in
cribriform plate of ethmoid

39. Source of the smell
Stimulus taken by the olfactory
receptors present in the nasal
epithelium
The axon component of olfactory
neuron receptors groups to form
olfactory nerve
Olfactory nerve enters the cranium
through cribriform plate present in
ethmoidal bone.
Traverse to olfactory bulb , which is
present In the olfactory groove.
In the olfactory bulb, the nerve
synapses with the mitral cells to
form synaptic glomeruli
Stimulus
reaches the
frontal lobe of
the brain.

40. Examination of the olfactory nerve :
Purpose of the test:
 To determine any impairment of smell is unilateral or
bilateral.
 Whether impairment is due to local nasal disease or neural
lesion.
Methods of testing:
Small bottles containing essences of very familiar odour are tested:
 Coffee
 Lemon
 Chocolate
 Asafetida, etc

42. There are a
number of disorder
of the sense of
smell, which can
result:
• Hyposomia
• Hypersomia
• Anosomia
• Parosmia

43. Anosmia
Anosmia is defined as the absence
of the sense of smell. It can be
temporary, permanent, progressive
or congenital.
Temporary anosmia can be caused by
infection (e.g. meningitis) or by local
disorders of the nose (e.g. common
cold)
 Permanent anosmia can be caused by
head injury, or tumours which occur in
the olfactory groove (e.g. meningioma).

44. • Anosmia can also occur as a result
of neurodegenerative conditions,
such as
 Parkinson’s or Alzheimer’s disease. In
these conditions, the anosmia
is progressive and precedes motor
symptoms but it is not often noticed by the
patient.
Anosmia is also a feature of a number
of genetic conditions such as
 Kallmann syndrome (failure to start or
finish puberty)
 Primary CiliaryDyskinesia (defect in
cilia causing it to be immobile)

45. Hyposomia
Hyposmia is much less common than loss of smell
( decrease the ability to smell )
Cause : allergies ,nasal polyps , head trauma
Hypersomia
Pregnant women commonly become
oversensitive to smell

46. Cranial Nerve II
• Optic nerve
 Component: Sensory
 Function: Vision
Origin: Back of the eyeball
 Opening to the Skull: Optic Canal

47. Visual information enters the eye in the
form of photons of light which are
converted to electrical signals in the retina.
The impulses are picked from the
photoreceptors of the eyes( rods and
cones )
Convergence of the retinal ganglion cells to
form optic nerve bundle
The optic nerve leaves orbit via optic canal
in the sphenoidal bone
In the middle cranial fossa both the
optic nerve tracts cross over to form
optic chiasm
The optic impulses are carried out
by the phenomenon of optic
radiation
The impulses are reach visual cortex
of the brain.
Response

48. Examination of the Optic nerve :
• Snellen chart test:
Visual field:
Purpose:
• To chart periphery of visual field.
• To detect position , size and
shape of the blind spot.

49. To asses visual field:
Purpose of the test:
To measure aquity of vision and determine if any disease is due to local or neural ocular
impairment.
To chart the visual field

50. •OPTIC NERVE DAMAGE
RETINA :
• Episode of total or partial loss of vision in one
eye caused by ischemia of the eye
Optic nerve :
• mononuclear ipsilateral blindness
• painless
• temporary loss of vision in one or both the eye

51. •OPTIC NERVE HYPOPLASIA (ONH)-
• A person with Optic Nerve Hypoplasia (ONH) has small optic
nerves from the eye to the brain.
• Some people with Optic Nerve Hypoplasia also have an abnormal
brain and a poorly functioning pituitary gland.
• Any or all of these problems in a mild or more serious form.

52. •Surgical Release of Pressure
Restores Vision
• Increased pressure in cerebral spinal fluid can
lead to stress on the optic nerve and result in a
loss of vision.
• In many cases, a procedure to release the
pressure is necessary to restore the ability to
see.
By a specialized procedure called optic nerve sheath
fenestration.

53. •Optic neuritis-
Features-
Pain and redness in and behind the eye
Papilloedema
 loss of vision
Causes bacterial infections

54. Cranial Nerve III
• Oculomotor nerve
 Component: Motor
Function:
Raises upper eyelid
Turns eyeball upward, downward and medially
Constricts pupil.
Accommodates the eye
 Origin: Anterior surface of the midbrain
 Opening to the Skull: Superior orbital
fissure

55. Occulomotor nerve arises
from the oculomotor nucleus
Nucleus present at the
anterior surface of the brain.
The pierces dura mater.
It traverses along the lateral
aspect of cavernous sinus
It exits the cranial cavity at
the superioir orbital fissure.
At this point it divides into:
Superior
branch
Inferior
branch
 Superior rectus
 Levator palpebrae
superioris
 Medial rectus
 Inferior rectus
 Inferior oblique

56. • Functions:
• Motor
– Innervates the majority of the extraocular muscles (levator palpebrae
superioris, superior rectus, inferior rectus, medial rectus and inferior oblique).
• Superior Branch
 Superior rectus – elevates the eyeball
Levator palpabrae superioris – raises the upper eyelid.
• Inferior Branch:
Medial rectus – abducts the eyeball
Inferior rectus – depresses the eyeball
Inferior oblique – elevates, abducts and laterally rotates the eyeball

57. • Functions:
• Parasympathetic:
Supplies the sphincter pupillae and the ciliary muscles
of the eye.
Sphincter pupillae – constricts the pupil, reducing the amount
of light entering the eye.
Ciliary muscles – contracts, causes the lens to become more
spherical, and thus more adapted to short range vision.
• Sympathetic –
 No direct function, but sympathetic fibres run with the
oculomotor nerve to innervate the superior tarsal muscle
(helps to raise the eyelid).

58. Examination of the Occulomotor and
trochlear nerve:
Purpose of the test:
 Inspect pupils to rule out a local disease, peripheral lesion or nuclear involvement.
 Examine eye movement and determine if detects in muscular origin or neural involvement.
Method of testing:
 Observation
 Presence or absence of ptosis and squint.
 Whether unilateral or bilateral
 Constant or variable.
 Size , shape and regularity of pupil.

59. CONSTRICTION AND DILATION OF PUPIL
ANALYSIS OF DIPLOPIA
EXAMINATION OF OCCULAR MOVEMENT

60. Clinical Relevance:
• Oculomotor nerve palsy:
• Oculomotor nerve palsy is a condition resulting from
damage to the oculomotor nerve. The most common
structural causes include:
Raised intracranial pressure (compresses the nerve against the
temporal bone).
Posterior communicating artery aneurysm
Cavernous sinus infection or trauma.

62. • Clinical Relevance:
Ptosis (drooping upper eyelid)
– due to paralysis of the levator palpabrae superioris and
unopposed activity of the orbicularis oculi muscle.
‘Down and out‘ position of the eye at rest –
due to paralysis of the superior, inferior and medial rectus,
and the inferior oblique (and therefore the unopposed
activity of the lateral rectus and superior oblique)
The patient is unable to elevate, depress or adduct the eye.
Dilated pupil –
due to the unopposed action of the dilator pupillae
muscle.

63. • Clinical Relevance:
oculomotor ophthalmoplegia is downward,
abducted eye on the affected side due to the
unopposed actions of the superior oblique and
lateral rectus muscles.
Strabismus (the inability to direct both eyes
toward the same object) as a result of
extraocular muscle paralysis. This leads to
diplopia (double vision).
Weber’s syndrome-
Midbrain lesion causing contralateral hemiplegia
and ipsilateral paralysis of the third nerve

64. Cranial Nerve IV
• TROCHLEAR NERVE
Component: Motor
Functions: eyeball downward and
laterally
Origin: Posterior surface of the
midbrain
Opening to the Skull: Superior
orbital fissure

65. Trochlear nerve originates
at trochlear nucleus
Nerve exits from the
posterior part of mid brain
Passes across the
subarachnoid space
Nerve pierces the dura
mater
Transverse along the
lateral wall of cavernous
sinus.
The nerve enters the orbits
of the eye via – superior
orbital fissure.

66. • Functions-
contraction of superior oblique
muscle
Intortion(rotates inward)
Abducts the eye
• Examination of the Trochlear
Nerve
The patient is asked to follow a
point (commonly the tip of a pen)
with their eyes without moving
their head. The target is moved in
an ‘H-shape’ and the patient is
asked to report any blurring of
vision or diplopia (double vision).

67. • Clinical Relevance:
Palsy of the Trochlear Nerve-
Trochlear nerve palsy commonly presents with
 vertical diplopia
 exacerbated when looking downwards and inwards.
Patients can also develop a head tilt away from the
affected side.
They are commonly caused by
microvascular damage from diabetes mellitus or
hypertensive disease.
 congenital malformation,
 thrombophlebitis of the cavernous sinus
 raised intracranial pressure.

68. • Clinical Relevance:
Extortion (outward rotation) of the affected eye
due to the unopposed action of the inferior
oblique muscle
Vertical diplopia (double vision) due to the
extorted eye.
Head tilt patient will often tilt his head opposite
the side of the affected eye in an attempt to
compensate for the outwardly rotated eye.

70. Cranial Nerve V
• TRIGEMINAL NERVE
Component: Mixed (motor &
sensory)
5th Cranial Nerve
Largest Cranial Nerve,
 Longest being vagus nerve
Also know as Nerves Trigeminus
or Trifacial Nerve

71. • Nuclei of trigeminal nerve
It has got 4 nuclei :
1) Main sensory nuclei
2) Spinal nuclei
3) principle sensory nuclei
4) Motor nuclei

72. • TRIGEMINAL GANGLION
known as Gasserian ganglion or semilunar ganglion.
Occupies a cavity (Meckel's cave) in the dura mater that contains the trigemina
l impression near the apex of the petrous part of the temporal bone.
crescentic or semilunar in shape, with its convexity directed anteriomedialy.
The three divisions of the trigeminal nerve emerges from this convexity

73. • ASSOCIATED ROOTS AND BRANCHES
The central processes of the ganglion cells forms the large sensory root of the tri
geminal nerve ,which is attached to pons at its junction with
the middle cerebellar peduncle.
 The small motor root of the trigeminal nerve is attached to the pons superomed
ialy to the sensory root.

74. TRIGEMINAL NERVEOPTHALMIC
MAXILLARY
MANDIBULAR
NASOCILLIARY
FRONTAL
LACIMAL
1) Supra
trochlear
2) Supra
orbital
1)Long ciliary
2)Infra trochlear
3)Posterior
ethmoidal
4)Anterior
ethmoidal
5)External nasal
Un
divided
Divided
ANTERIOR
DIVISION.
N. Lateral
pterygoid
N .masseter
N. Temporalis
Buccal nerve
POSTERIOR
DIVISION.
Auriculotemporal
nerve
Lingual nerve
Inferior alveolar
nerve
-Mylohyoid nerve
-Mental nerve
-Incisive nerve
1)Nerve
to
spinosus
2)Nerve
to medial
pterygoid
Meningeal
branch
1.Middle
superior
alveolar
2. Anterior
superior
alveolar
3. Facial:
-palapebral
-nasal
-superior
labial
1.Zygomati
co
temporal
2.Zygomati
co facial
1.Orbital
2.Palatine
-greater p.
-lesser p
3.Nasopalatine
4.Lacrimal
5. pharyngeal
Within
cranial
cavity
Pterygopal
atine
ganglion
Zygomatic Infraorbital
Posterior
superior
alveolar

75. Opthalmic

76.  Superior and smallest branch
 Completely sensory
 Arises from antero medial end of trigeminal ganglion
 Just before or after entering the cranium , ophthalmic nerve divides into 3 branches
1) LACRIMAL BRANCH
• Smallest branch.
• Enters the orbit through the lateral part of superior orbital fissure.
 Supplies lacrimal gland
 conjunctiva.
 ends in upper eye lid .
NASOCILLIARYFRONTALLACIMAL
1)Long ciliary
2)Infra trochlear
3)Posterior ethmoidal
4)Anterior ethmoidal
5)External nasal
1) Supra trochlear
2) Supra orbital
opthalmic

77. 2) NASOCILLIARY
• Intermediate in size between lacrimal and frontal .
• Enters the orbit through lateral part of superior orbital fissure.
• Runs laterally between superior oblique and lateral rectus muscle.
BRANCHES
1. Anterior Ethmoidal – Middle and anterior ethmoidal sinus, Medial internal nasal , Lateral internal nasal
2. Posterior Ethmoidal – Posterior ethmoidal air sinus , Sphenoidal air sinus
3. Long cilliary ganglionic branches – Iris of cornea
4. External nasal – Skin of the ala , Tip of the nose
5. Infra trochlear – Both eyelids , Side of the nose , Lacrimal sac

78. 3) FRONTAL
• largest branch of ophthalmic division
• Enter the orbit through lateral part of superior orbital fissure
• Runs above levator palepebrae superioris and divides into:
Supra orbital: supplies
 Conjuctiva
 Upper eye lid
 Upper forehead near mid line
Supratrochlear: supplies
 Upper eyelid, scalp
 Frontal sinus, forehead

79. Maxillary

80. It leaves the trigeminal ganglion between the ophthalmic and mandibular divisions as a flat plexiform band Passes
slightly medial to lateral wall of cavernous sinus Gives a sensory branch to the dura matter within the cranium It is
intermediate division of trigeminal nerve.
Then leaves the cranium through foramen rotandum, which is located in the greater wing of sphenoid bone. Once
outside the cranium, it crosses the uppermost part of the pterygopalatine fossa
As it crosses the pterygopalatine fossa it gives
 Sphenopalatine Ganglionic Branch
 posterior superior alveolar nerve
 Zygomatic Branches
 Infraorbital branch
. The maxillary division emerges on the anterior surface of face through the infraorbital foramen, where it divides into
its terminal branches, supplying the skin of the face, nose, lower eyelid and upper lip
Maxillary

82. Infraorbital nerve
Infra orbital fissure

84. Within
cranial cavity
In the
Pterygopalatine
Fossa
In the
Infraorbital
canal
On the face.
Meningeal
branch
1.Middle
superior
alveolar
2. Anterior
superior
alveolar
1.Inferior
palapebral
2.External nasal
3. superior labial
Posterior
superior
alveolar
Spheno
palatine
1.Zygomatico
temporal
2.Zygomatico
facial
1.Orbital
2.Palatine
-greater p.
-lesser p
3.Nasopalatine
4.Lacrimal
5. pharyngeal

85. 1) WITHIN THE CRANIAL
CAVITY
Meningeal branch
 Meningeal branch also
known as nervus meningeus
medius.
 It lies within the cranium.
 It accompanies the middle
meningeal artery to supply
the duramater.

86. Starts in the pterygopalatine fossa.
Enters the orbit through the inferior orbital fissure.
Runs along the lateral wall to reach zygomatic bone Just before/after
entering zygomatic bone, it gives of two terminal branches.
ZYGOMATIC BRANCH
 Zygomaticcotemporal: a communicating secretomotor fibres given to the lacrimal gland
through lacrimal nerve.
 Zygomaticofacial: sensory supply to the skin over zygomatic prominence and to the anterior
part of the temple.
2) WITHIN THE PTERYGOPALATINE FOSSA

87. Zygomaticofacial branch
Pterygopalatine ganglion

88. POSTERIOR SUPRIOR ALVEOLAR BRANCH
It descends from the main trunk of the maxillary division in the
ptergopalatine fossa.
Through the pterygopalatine fossa,it reaches posterior surface of the
body of maxilla. From here it enters maxilla through the PSA canal.
Travel down the posteriolateral wall of the maxillary sinus.
 Provides sensory innervation to the mucous membrane of the sinus
 Continuing downward it provides:
 sensory innervation to the alveolus
 periodontal ligaments and pulpal tissues of the maxillary 3rd ,2nd and 1st
molar.

90. PTERYGOPALATINE GANGLION
• This ganglion is also known as sphenopalalatine ganglion or ganglion of
Hay Fever.
• The ganglionic branches of maxillary nerve suspend the ganglion in the
pterygopalatine fossa
• It is the largest peripheral parasympathetic ganglion .
Branches of pterygopalatine nerve includes those that supply five areas:-
1)Orbit
2)Nasal
a) Superior Posterior Nasal
i. Medial
ii. Lateral
b) Nasopalatine
3)Palate
a) Greater (Anterior)
b) Lesser (Middle & Posterior)
4) Pharynx
5) Lacrimal

91. 1) Orbital branch:
Supplies periosteum of orbit
2) Pharyngeal branch:
 It leaves the posterior part of
pterygopalatine ganglion and passes
through the pharyngeal canal .
It is distributed to the mucous
membrane of the nasal part of
pharynx, posterior to eustachian
tube

92. Greater palatine nerve descends through pterygopalatine canal from the
ganglion and emerges from greater palatine foramen of hard palate.
Then moves anteriorly between mucoperiosteum and hard palate up to
1st premolar supplying sensory innervation to palatal soft tissue and
bone.
Then communicates with nasopalatine
Middle palatine and posterior palatine emerges from lesser palatine
foramen and supply soft palate and tonsillar region respectively
3) Palatine branch: Arises as:
 greater palatine (anterior)
 lesser palatine (middle and posterior)

94. It passes across roof of nasal -Reaches to floor of
nasal cavity n give branch to anterior part of nasal
septum and floor of nasal cavity.
Enters Incisive canal and enters oral cavity
through incisive foramen
-It provides sensation to palatal mucosa of
premaxilla region
4) Nasal branch:
Supplies to:
 mucosa of superior and inferior conchae
 posterior ethmoidal sinus
 posterior portion of nasal septum.
 It also includes Nasopalatine branch.

95. INFRAORBITAL NERVE
Enters the orbit through the IOF Runs forward
on the floor of the orbit First in the infraorbital
groove, then in the canal Here it gives two
branches
a) ANTERIOR SUPERIOR ALVEOLAR NERVE (ASA):
• It is a relatively larger branch Given off
from the infraorbital nerve.
• And exits from canalis sinousus.
 Central and Lateral Incisors
 Canine ,
 Periodontal Tissues
 Buccal Bone
 Mucous Membrane Of These Teeth.
3) WITHIN THE INFRAORBITAL CANAL

96. b) MIDDLE SUPERIOR ALVEOLAR
NERVE (MSA):
• Arises from the infra orbital
nerve.
• Provides sensory innervation
to :
 maxillary premolars and the
mesiobuccal root of the first
molar
 periodontal tissues
 buccal soft tissues
 bone in the premolar region.

97. c) THE TERMINATES BY: emerging on the face through infraorbital
foramen giving out its terminal branches
4) WITHIN THE FACE:
 The Inferior Palpebral:-
supplying the skin of the lower
eyelid
 The External Nasal Branch:-
providing sensory innervation
to skin of lateral part of the
nose
 The Superior Labial Branch:-
supplying the skin and mucous
membrane of the upper lip.
Inferior palapebral
External nasal

98. MANDIBULAR NERVE

99. MANDIBULAR NERVE
Largest division of trigeminal nerve
Mixed in nature
Has a large sensory root and a small motor root
The sensory root originates from trigeminal ganglion whereas
the motor root originates in the pons and medulla oblongata
The motor root lying medial to sensory root
The two roots emerge from the cranium separately through
the foramen ovale
They unite just outside the skull and form the main trunk of
3rd division

100. MANDIBULAR
Divided Un divided
ANTERIOR
DIVISION.
N. Lateral
pterygoid
N .masseter
N. Temporalis
Buccal nerve
2)Nerve to
medial
pterygoid
1)Nerve to
spinosus
POSTERIOR DIVISION.
Auriculo temporal nerve
Lingual nerve
Inferior alveolar nerve
-Mental nerve
-Incisive nerve
--Mylohyoid nerve

101. • Meningeal Branch
Enters the skull through foramen spinosum (along with the middle
meningeal artery) Supply the dura matter of the middle cranial fossa
This nerve is also called NERVUS SPINOSUS
• NERVE TO MEDIAL PTERYGOID
It is a motor nerve to medial pterygoid muscle
BRANCHES OF THE UNDIVIDED NERVE:

102. 1) BRANCHES FROM ANTERIOR DIVISION:
• Motor Branch - To the muscles of mastication.
• The anterior division is smaller than the posterior division.
• Includes:
N. Lateral pterygoid
N .masseter
N. Temporalis
Buccal nerve
• Under the lateral pterygoid nerve,it gives off some branches, i.e.
 The deep temporal nerve- to the temporal muscle
 The masseter nerve- providing motor innervation to masseter muscle
Lateral pterygoid nerve- providing motor innervation to the lateral pterygoid muscle
BRANCHES OF THE DIVIDED NERVE:

103. Follows the inferior part of the temporal muscle
Emerges under the anterior border of the masseter muscle at
the level of occlusal plane of the mandibular 3rd and 2nd molar
Usually passes between the two heads of the lateral pterygoid
reaches the external surface of the muscle
Crosses in front of the ramus and enters the cheek through
buccinator muscle.
THE BUCCINATOR NERVE

105. • Provides sensory innervation
to:
Skin over the anterior part of
buccinator .
Buccal gingiva of mandibular molars
Mucobuccal fold in that region.

106. 2)THE POSTERIOR
DIVISION
• Larger division
• Mainly sensory
•It branches into:
 Auriculo temporal Nerve
 Lingual Nerve
 Inferior Alveolar Nerve
(Only Motor)

107. • AURICULOTEMPORAL NERVE
• The auriculo temporal branch arises from the trigeminal nerve as two roots:
Superior root – comprises sensory fibres.
Inferior root – carries secretory-motor parasympathetic fibres, originating from
CN IX, to the parotid gland.
• The two roots converge in close proximity to the middle meningeal artery. After
converging, the secretory-motor fibres run to synapse in the otic ganglion, while the
sensory fibres pass through the ganglion without synapsing .

108. • BRANCHES OF AURICULOTEMPORAL NERVE
 Two anterior auricular branch-supply the skin of tragus and sometimes
small part of adjoining helix and the temporomandibular joint
Two branches to external acoustic meatus-supply skin of meatus and the
tympanic membrane
 Superficial temporal branch- supply skin in the temporal region and
connects with the facial and zygomaticotemporal nerves

109. • THE LINGUAL NERVE
 Second branch of the posterior division of mandibular nerve .

110. Runs between the tensor veli palatini and lateral pterygoid , where it is
joined by chorda tympani branch of facial nerve .
It descends to rest between the ramus and medial pterygoid muscle in
the pterygomandibular space
It runs anterior and medial to the inferior alveolar nerve whose path is
parallel to it.
It then proceeds anteriorly across the muscles of the tongue Looping
medial to submandibular duct (wharton’s duct) to deep surface of
submandibular and sublingual gland where it breaks up into terminal
branches
It then continues to reach the side of the base of the tongue slightly
below and behind the mandibular 3rd molar. Here it lies just below the
mucous membrane in the lateral lingual sulcus.

112. • SUPPLY OF LINGUAL NERVE
• Supplies:
 the mucosa of the floor of the
mouth
lingual gingivae
 Mucosa of anterior two third of the
tongue
Also carries postganglionic fibres
from submandibular ganglion to
sublingual and anterior lingual
glands

113. • INFERIOR ALVEOLAR
Largest branch of the mandibular division .

114. Descends medial to the lateral pterygoid muscle and
lateroposterior to lingual nerve
Passes between the sphenomandibular ligament and the
mandibular ramus to enter the mandibular canal via mandibular
foramen
It divides into its terminal branches”
•Mental nerve
•Incisive nerve
Through out its path it is accompanied by inferior alveolar artery
and inferior alveolar vein
Nerve travels anteriorly in the canal till it reaches the mental
foramen

115. • Mental Nerve:
Exists the canal through the mental foramen between
and just below the apices of the premolar,and divides
into three branches that innervates: Continues forward
in the bony canal giving off branches to:
 Premolar
 Canine
Incisors
Associated Labial Gingiva
Incisive Nerve:
Skin of the chin
Skin of the lower lip
 Buccal mucous membrane from second premolar to
the midline i.e central incisor region.

116. • THE MYLOHYOID NERVE
Just before entering the mandibular
canal, the inferior alveolar nerve gives
off a small mylohyoid branch
It pierces the sphenomandibular
ligament and enters a shallow groove
on medial surface of mandible
Follows a course roughly parallel to
inferior alveolar nerve passes below
the origin of mylohyoid muscle.
 It is a mixed nerve

117.  Provides motor innervation to:
 1. Mylohyoid and anterior belly of
digastric
2. Sensory fibres to inferior and anterior
surfaces of mental protuberance
3. Mandibular incisors (sometimes)

118. Examination of the trigeminal nerve :
Purpose of the test:
 To determine the sensory impairment.
 To determine unilateral or bilateral motor weakness and determine upper motor lesions and lower motor lesions
Method of examination:
 superficial sensory assessments from mainly touch and pain.
 Forehead and upper part of side of the nose (ophthalmic)
 Malar and upper lip (maxillary)
 Chin and anterior part of the tongue (mandibular)
Interpretation:
 Total loss of sensation- lesion of ganglia or sensory root.
 Total sensory loss over 1 divisions- partial lesion of ganglion or root.
 Touch only lost- pontine lesion.

119. Motor assessment:
 Muscles of mastication
 Ask patient ti bite against resistance.
 Ask patient to protrude mandible against
resistance.
 Ask patient to go into lateral excursive
movements against resistance.
 Jaw jerk

120. INNERVATION TO PRIMARY DENTITION

128. Applied anatomy of trigeminal erve:
• 1.Trigeminal neuralgia.
• 2. Herpes zoster ophthalmicus.
• 3.Wallenberg Syndrome.

129. Trigeminal neuralgia
• Also known as Fothergill’s disease Tic douloureux (painful jerking)
• It is defined sudden, usually, unilateral, severe, brief, stabbing ,
lancinating, recurring pain in the distribution of one or more branches
of trigeminal nerve.
• PATHOGENESIS OF TRIGEMINAL NEURALGIA
• It is usually idiopathic.
• The probable etiologic factors are:-
 Intra cranial tumours:-Traumatic compression of the trigeminal nerve by
neoplastic or vascular anomalies eg arteriovenous malformations
Infections : infections involving 5th cranial nerve.
 Intracranial vascular abnormalities

130. CLINICAL
CHARACTERISTICS:
-
• Sudden,Unilateral, sharp shooting
• lancinating shock like pain elicited by slight touching.
• superficial trigger points which radiates across the distribution of one
or more branches of the trigeminal nerve
• pain rarely crosses the midline
• pain is of short duration and last for few seconds to minutes in extreme
cases patient has a motionless face called the frozen or mask like face
presence of intraoral or extra oral trigger points

131. • TRIGGER ZONE
• Provoked by obvious stimuli like
Touching face at particular site.
• Chewing ,Speaking ,Brushing
,Shaving ,Washing the face
• The characteristic of the disorder
being that the attacks do not
occur during sleep.

132. DIAGNOSIS:-
• CLINICAL EXAMINATION with
HISTORY is mandatory
• Response to treatment with
tablet of carbamazepine.
• Injections of local anaesthetic
agents into patients trigger zone
gives temporarily relief from
pain.

133. TREATMENT
Medical treatment
 Carbamazepine and phenytoin are the traditional anticonvulsants given
Surgical treatment:-
 Peripheral injections
 Peripheral neurectomy
 Cryotherapy
 Peripheral radiofrequency
 Neurolysis(thermocoagulation)

134. • THE ALCOHOLIC INJECTIONS:-
• 95% ABSOLUTE alcohol in small
quantities 0.5 to 2 ml is given in
peripheral branches of trigeminal
nerve.
• Side effect:- Repeated injections
may cause Local tissue toxicity
Inflammation Fibrosis

135. HERPES ZOSTER OPHTHALMICUS:-
• Caused by Varicella zoster
• Predilection for naso ciliary
branch of ophthalmic division of
the trigeminal nerve.
• CLINICAL FEATURES:-
• Cutaneous lesions:-
 Rash
Vesicle
 Pustule
 crust
 permanent scar.

136. • OCULAR LESIONS:-
Periorbital pain
 Oedema
 Hyperaesthesia
 Conjunctivitis
 Corneal scarring
• TREATMENT:-
• Acyclovir 800mg 5 times /day within 4 days of onset of rash
• Analgesics Antibiotic ointments.
• Systemic steroids 60mg/day Corneal grafting