1. Dr. Amit T. Suryawanshi
Oral and Maxillofacial Surgeon
Pune, India
Contact details :
Email ID - amitsuryawanshi999@gmail.com
Mobile No - 9405622455

2. CONTENTS
 BASIC NEUROANATOMY
 Origin of nervous system
 Divisions of nervous system
 Cranial nerves

3. NEUROANATOMY
Basic organization of the nervous system
• Sensory
stimuli
Sensory
Nerves
BRAIN
• Correlation
• Coordination
Motor Nerves
• Muscles
• Glands
etc.

4. The Nervous system
The nervous system is an organ system containing
a network of specialized cells called neurons that
transmit signals between different parts of the
body. coordinate the actions .
The nervous system consists of two parts,
1. Central nervous system
2. Peripheral nervous system.

5. Origin Of Nervous System

6. EMBRYONIC
ECTODERM
NERVOUS
SYSTEM
NEURAL
PLATE
NEURAL
CREST CELLS
PNS ANS
NEURAL
TUBE
CNS
Origin Of Nervous System

7. Divisions of Nervous system
Nervousrsystem
 CENTRAL NERVOUS SYSTEM
Brain & Spinal cord
 PERIPHERAL NERVOUS SYSTEM
Cranial & Spinal nerves
and their associated ganglia
Autonomic
Nervous
system
Sensory
Divisions
Somatic
Nervous
system
Motor
Divisions
Parasympathetic
N. system
Sympathetic
N. system
Enteric N.
System

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

9. Organization of the Nervous System
Divisions of Nervous System :
1. Central Nervous
System –
2. Peripheral Nervous
System -
The nervous system
outside the brain and
spinal cord
Consists of:
31 Spinal nerves
- Carry information
to and from the
spinal cord.
12 Cranial nerves
- Carry information
to and from the
brain.
- Ganglia
The brain
the spinal cord
The Main center
of integration
and control

10. Divisions of Nervous System -

11. 1. 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 and initiating
appropriate and coordinated — motor outputs.

12. Spinal Cord -
- Conducts sensory information from
the peripheral nervous system (both somatic
and autonomic ) to the brain
- Conducts motor information from the brain to our
various effectors
-skeletal muscles
-cardiac muscle
-smooth muscle
-glands

13. Peripheral Nervous System
Responsible for communication between the CNS and
the rest of the body .

It is divided into:
 Sensory division ( Afferent division )

 Motor division ( Efferent division )


14. Sensory division ( Afferent division ) –
-Conducts impulses from RECEPTORS to the CNS
-Informs the CNS about the state of the body
-( interior and exterior )
- Sensory nerve fibers can be ,
SOMATIC - Conduct impulses from skin, skeletal
muscles and Joints to CNS
VISCERAL –Conduct impulses from smooth muscles,
cardiac muscles, and glands (Internal organs) to CNS.

15. Motor Division ( Efferent Division ) -
 It is divided into:
Somatic nervous system -
 VOLUNTARY (generally)
Conducts impulses from the CNS to skin , skeletal muscles ,
joints
Autonomic nervous system -
 INVOLUNTARY (generally)
 Conducts impulses from the CNS to smooth muscles, cardiac
muscles, and glands (Internal organs )

16. Autonomic Nervous System-
 Divided into:
 Sympathetic Nervous
System -
 “Fight or Flight”
 Parasympathetic
Nervous System -
 “Rest and Digest”
These 2 systems are antagonistic.

17. Sympathetic Nervous System -
The
sympathetic
nervous
system aids in
the control of
most of the
body's internal
organs.
Stress — as in
the flight-or-fight
response.

18. Parasympathetic Nervous System -
“Rest and Digest”
Phenomenon
- generally works
to promote
maintenance of
the body at rest.

19. Enteric Nervous System
The enteric nervous system is a
meshwork of nerve fibers that
innervate the
viscera
Gastrointestinal tract,
 Pancreas
 Gall bladder.

20. NEURON-Neuron
(nerve cell)–
It is basic structural and
functional unit of the
nervous system.

21. Types of NEURON

22. NEUROANATOMY
Neuron consists of :
 a cell body containing
nucleus – the
Neuronal soma.
 Multiple number of
processes -dendrites
and axons

23. NEUROANATOMY
Function Of Neurons -
Neurons produce and
conduct nerve impulses.
 Dendrites conduct
information towards the
cell body
 Axons conduct impulses
away from cell body

24. Synapse and Neurotransmitters
A synapse is the site of
functional contact
between axon and
another neuron or
organ.
Neurotransmitters are
released at synapses
and they help in
transmission of
impulses.

25.  Afferent neurons
 - carry sensations of touch , pain, temperature
and pressure. Therefore they are called as
sensory fibers .
Efferent neurons
- carry impulses away from the central
nervous system.

26.  NUCLEUS & GANGLION
 NUCLEUS - is a compact
group of nerve cell bodies of
similar form and function,
located inside the CNS.
 GANGLION – is a similar
group of nerve cell bodies
located outside the CNS.

27. NEUROANATOMY
The PNS has three main types of nerves:
1. Cranial Nerves
2. Spinal Nerves and
3. Autonomic Nerves
All cranial nerves are attached to the
brainstem, except for cranial nerve XI,
Accessory Nerve.
which is attached to the spinal cord.

28. spinal nerves -
 All spinal nerves are attached to the spinal cord.
All spinal nerves have dorsal and ventral roots.

29.  The autonomic nerves run through the roots
of cranial or spinal nerves to ganglia or
autonomic plexuses in the walls of the viscera
(smooth muscles and glands)
They also return sensory impulses to CNS from
sensory receptors in viscera.

30. Cranial Nerves
I . Olfactory Nerve
II . Optic Nerve
III. Oculomotor Nerve
IV. Trochlear Nerve
V. Trigeminal Nerve
VI. Abducent Nerve
VII. Facial Nerve
VIII. Vestibulocochlear Or Auditory N.
IX. Glossopharyngeal Nerve
X. Vagus Nerve
XI. Accessory Nerve
XII. Hypoglossal Nerve

32. OLFACTORY NERVE
 Entirely sensory in function.
 Arises from olfactory
receptor nerve cells in
the
mucous membrane of nasal
cavity.
 Bundles of these nerve
fibers pass through
openings of cribriform plate
of ethmoid bone
and synapse in the
olfactory bulb.

33.  From olfactory bulb ,the second order nerve fibers
pass through the olfactory tract to the olfactory
cortex in cerebrum.
 The olfactory cortex in cerebrum is
responsible for appreciation of olfactory
sensations. i.e. Sensation of Smell.

34. OPTIC NERVE
 Entirely sensory in function.
• The Optic Nerve passes from the
eyeball through the optic canal into the
middle cranial fossa .

35. The two optic nerves
join below the base of
the diencephalon to
form optic chiasma
and then divides into
two optic tracts

36. Optic nerve transmits visual information from light-sensitive
receptors on the retina of the eye to the brain
for analysis, interpretation .

37. OCULOMOTOR NERVE
 Entirely motor in function.
 Oculomotor nerve nuclei:
Two nuclei –
1. the main motor nucleus situated in midbrain.
2. the parasympathetic nucleus situated
posterior to the motor nucleus

38.  Course of occulomotor nerve :
The occulomotor nerve emerges from the
midbrain- then continues in the middle cranial
fossa in the lateral wall of cavernous sinus.
Here it divides into superior and inferior ramus
which enter the orbital cavity through superior
orbital fissure.

40. The occulomotor nerve supplies parasympathetic innervation to
the intraocular muscles.
And somatic innervation to the extraocular muscles.
Parasympathetic fibers synapse in ciliary ganglion.

41. The occulomtor nerve
supplies the following
extrinsic muscles of
eye :
1. Levator palpebrae
superioris
2. Superior, medial and
inferior rectus
3. Inferior oblique

42.  The oculomotor nerve is responsible for:
1. Lifting the upper eyelid.
2. Turning the eye upward, downward and
medially.
3. Constricting the pupil and accomodating the
eye.

43. TROCHLEAR NERVE
 Entirely motor in
function.
 Trochlear nerve
nucleus –
Situated in midbrain and
lies inferior to the
Oculomotor nucleus.

44.  Course of trochlear nerve :
Leaves the brainstem and immediately decussates
with the nerve of opposite side .
It passes through the middle cranial fossa in the
lateral wall of cavernous sinus and enters orbit
through superior orbital fissure.

45.  The nerve supplies superior oblique musle
of eyeball.
It assists in turning eye downward and laterally.

46. TRIGEMINAL NERVE
Course & relations
Anterior aspect of Pons
( sensory and Motor Root )
Middle Cranial Fossa
Meckel’s cavity ( Trigeminal Ganglion)
Ist Division
Ophthalmic
Superior orbital
fissure
IInd Division
Maxillary
Foramen Rotundum
IIIrd Division
Mandibular
Foramen Ovale

49. OPHTHALMIC DIVISION
Course & relations
Trigeminal Ganglion
Middle Cranial Fossa
Lateral wall of Cavernous Sinus
Superior Orbital Fissure
Orbit
-Lacrimal
-Frontal
-Nasociliary

50. OPHTHALMIC DIVISION

51. LACRIMAL NERVE
Course & Relations
Superior Orbital Fissure
Lateral wall of Orbit
Above the Lateral Rectus muscle
Lacrimal Gland

52. Frontal nerve
Course & relations
Superior Orbital Fissure
Levator Palpebrae Superioris
Rim of Orbit
Supra-orbital Supra-trochlear
Supra-orbital Foramen

53. NASO-CILIARY NERVE
Course & relations
Superior Orbital Fissure
Within common tendinous ring of Recti
Optic Nerve
Below superior rectus & superior oblique
Medial orbital wall
Anterior
Ethmoidal
Posterior
Ethmoidal
Long
Ciliary
Infra-trochlear
External nasal Internal nasal

54. MAXILLARY NERVE
- Branches and Course -
Gasserion Ganglion
Foramen Rotundum
Pterygopalatine Fossa
Infra –Orbital Canal
Infra –Orbital Foramen
Face
Middle Meningeal N.
-Pterigopalatine N
-Posterior superior
alveolar N
-Zygomatic N
Anterior superior alveolar N
Middle superior alveolar N
-Inferior palpebral
-External nasal
-Superior labial

55. MAXILLARY DIVISION

57. Maxillary Nerve Branches
(within pterigopalatine fossa )
Zygomatic N
Inferior Orbital
Fissure
Zygomatico-facial
Supplies-
Facial prominence
Of cheek
Zygomatico-temporal
Supplies-
Skin of temple

58. Continued -
Pterygopalatine Nerves
Orbital Nasal Palatine
Nasopalatine N. Greater
palatine n.
middle
palatine n.
posterior
palatine n.
Posterior
Hard
palate
Posterior superior Alveolar N.
Soft palate,
Tonsil,uvula
Soft
palate
Maxillary molars , buccal
Mucosa in molar region

59. Maxillary Nerve Branches
( within infraorbital canal )
Middle superior
alveolar nerve
Anterior superior
alveolar nerve
Supplies-
Maxillary Incisors,
canine
Supplies –
Maxillary premolars

60. Maxillary Nerve Branches ( on the face )
Inferior
Palpebral
branches
External
nasal
branches
Superior labial
branches
Lower
Eyelid
Upper
Side of Lip,cheek
Nose

61. - Superior dental plexus -

62. MANDIBULAR NERVE
Course & Relations
Gasserion Ganglion
Motor root
Foramen Ovale
Main
trunk
Nerve to medial pterygoid
Anterior
division
Posterior
division
Buccal
Nerve to Masseter
Nerve To Temporalis
Nerve to Lateral
Pterygoid
Auriculo-temporal
Mylohyoid
Nerve
Superficial
temporal
Cutaneous
Mental
Incisive
Lingual
Inferior alveolar
sensory root
Nervous spinosus-

64. ABDUCENT NERVE -
ABDUCENT NERVE
 Entirely motor and supplies the lateral rectus
muscle of the eyeball.
 Abducent nerve nucleus :
situated in pons

65.  Course of abducent nerve :
The nerve fibers emerge from the pons from the
groove between pons and medulla oblongata.
It passes through cavernous sinus and lies below
the internal carotid artery.
The nerve enters the orbit through superior orbital
fissure.

66.  Abducent nerve :

67. FACIAL NERVE

68. Course and Branches of Facial Nerve

69. -Course-
PONS
Motor
root
Medulla oblongata
Sensory
root
INTERNAL AUDITORY MEATUS
PETROUS PART OF TEMPORAL
BONE
FACIAL CANAL
STYLOMASTOID FORAMEN
PAROTID GLAND
FACIAL MUSCLES
(GENICULATE GANGLION )
PAROTID PLEXUS
GREATER PETROSAL
NERVE TO STAPEDIUS
CHORDA TYMPANI
POSTERIOR AURICULAR
N . POST. BELLY OF DIGASTRIC
N . STYLOHYOID

70. • Greater petrosal nerve -
- provides motor innervation to lacrimal
gland , mucosal glands of the nose, palate, and
pharynx.
- carries special sensory taste fibers from
the palate .
• Nerve to stapedius -
provides motor innervation
for stapedius muscle in middle ear
• Chorda tympani -
carries special sensory taste fibers from
the anterior 2/3rd of the tongue.

71. Outside skull -
(Distal to stylomastoid foramen)
• Posterior auricular nerve -
• Nerve to Posterior belly of Digastric
• Nerve to Stylohyoid muscle .

72. Facial nerve enters parotid gland and forms parotid plexus
Parotid
Plexus

73. Functions -
• Its main function is motor
control of most of the muscles of
facial expression.
• The facial nerve also
supplies parasympathetic fibers
to the submandibular
gland and sublingual
glands via chorda tympani

74. Vestibulocochlear Nerve Or Auditory Nerve
-It is Sensory nerve .
-It consists of two
roots
- Vestibular root
- Cochlear root

75. Course -

76. Vestibular root --
Vestibular root transmits impulses from
vestibular apparatus ( Balance )
Cochlear root --
Cochlear root transmits impulses from
auditory apparatus (Sound )

77. Functions -
• Auditory nerve transmits sound and
equilibrium (balance) information from
the Internal ear to the Brain .

78. Glossopharyngeal nerve
It originates from medulla oblongata
Nuclei -
Inferior salivatory nucleus
Nucleus ambiguus
Nucleus of solitory tract

79. Glossopharyngeal nerve

80. Glossopharyngeal nerve
Superior Ganglion
Inferior Ganglion
•Branches -
•Tympanic nerve (s)
•Branch to carotid
sinus (s)
•Branch to
Stylopharyngeus
muscle (m)
•Tonsillar branches
(s)
Lingual Branches
•(S)
•Pharyngeal branches
(m)

81. •Tympanic nerve -
Sensory fibers supply the middle ear.
Secretory fibers supply the parotid gland
•Nerve to carotid sinus -
Receives sensory information from ‘
Chemoreceptors in Carotid body .
Baroreceptors in carotid sinus .
•Nerve to Stylopharyngeus muscle
•Tonsillar branches (s)

82. Lingual Branches -
Receives sensory information from posterior 1/3rd of the tongue.
•Pharyngeal branches -
Innervate constrictor muscles of the pharynx.

83. It originates from medulla oblongata
Nuclei -
-Nucleus ambiguus
-Nucleus of solitory tract
( superior part & inferior part )

84. COURSE OF VAGUS NERVE

85. VAGUS NERVE (MIXED)
BRANCHES -
Superior Ganglion
- Meningeal nerve
- Auricular nerve
Inferior Ganglion
- Pharyngeal branches
- Superior laryngeal nerve
- external laryngeal n.
- internal laryngeal n.
- Recurrent laryngeal
- Cervical Carotid branches
-Anterior esophageal plexus
-gastric, celiac, hepatic branches

86. •It supplies -
•Cricothyroid muscle
Levator veli palatini muscle
•Salpingopharyngeus muscle
•Palatoglossus muscle
•Palatopharyngeus muscle
•Superior, middle and
inferior pharyngeal constrictors
•Muscles of the larynx (speech)

87. Accessory nerve (motor)
Course -

88. Cranial root –
Cranial root joins Vagus nerve and innervates
- all laryngeal muscles except cricothyroid
Spinal root -
Spinal root innervates
-Trapezius
-Sternocleidomastoid

89. Hypoglossal nerve (motor)
COURSE & RELATIONS
Medulla Oblongata
(Hypoglossal Nucleus)
Hypoglossal Canal
Behind Vagus Nerve
Between IJV & ICA
Posterior Belly of Digastric
Tongue(Intrinsic and extrinsic muscles)

91. It supplies --
Extrinsic muscles
Genioglossus
Hyoglossus
Styloglossus
Intrinsic muscles
Superior longitudinal
Inferior longitudinal
Verticalis
Transversus
Except Palatoglossus which is supplied by cranial part of accessory nerve

92. References
 Gray’s Anatomy
 Oral and maxillofacial surgery – Laskin
 Atlas of Anatomy - Anne Gilroy
 LA – Malamed
 Guyton (physiology )
 Ganong (physiology )
 Internet

93. Thank you