Brief review about Cranial Review.

2. CONTENTS
coIntroduction.
Organization of Nervous System.
Related Terminologies.
Cranial Nerves.
Detailed study of
V. Trigeminal nerve
VII. Facial nerve
IX. Glossopharyngeal nerve
X. Vagus nerve
XII. Hypoglossal nerve
References.

3. INTRODUCTION
Nervous system - Controls the functions of
the body.
Composed basically of specialized cells, whose
function is to receive sensory stimuli and to
transmit them to effector organs, whether
muscular or glandular.

4. ORGANIZATION
Organization of
nervous system
Central
nervous
system
Brain Spinal cord
Peripheral
nervous
system
Somatic
nervous
system
Spinal
nerves
(31 pairs)
Cranial
nerves
(12 pairs)
Automonic
nervous
system
Sympathetic
Para-
sympathetic

5. RELATED TERMINOLOGIES
Neuron :
Structural and
functional unit
of nervous system.

6. Nucleus : Discrete group of nerve cell bodies
in the central nervous system.
Ganglion : Group of nerve cell bodies located
outside central nervous system.

7. Tract : Bundles of nerve fibres found in the
central nervous system.
Nerve : Bundles of nerve fibres found in the
peripheral nervous system.
Plexus : A network of
intersecting nerves.

8. Visceral Nerves : They are the nerves which
supply the different viscera, the organs within
the body cavity.
Somatic nerves : They supply somatic
structures (skin and muscles).

9. Afferent nerve : Sensory or receptor neurons -
carry nerve impulses from receptors or sense
organs toward the central nervous system.
Efferent nerve : Motor or effector neurons –
carry nerve impulses away from the central
nervous system to effectors such
as muscles or glands.

10. General : Refers to stimuli conducted
throughout the entire body, common to both
cranial and spinal nerves.
e.g. touch, pressure, vibration, pain and
proprioception.
Special : Afferent impulses are encoded by
highly specific sense organs and transmitted
to the brain in certain cranial nerves.
e.g. Olfaction, vision, taste, hearing and
vestibular function.

11. CRANIAL NERVES
I.Olfactory nerve
II.Optic nerve
III.Oculomotor nerve
IV.Trochlear nerve
V.Trigeminal nerve
VI.Abducens nerve
VII.Facial nerve
VIII.Auditory nerve
IX.Glossopharyngeal nerve
X.Vagus nerve
XI.Accessory nerve
XII.Hypoglossal nerve
Trochlear

12. CLASSIFICATION
Sensory cranial nerves
 Ⅰ Olfactory nerve
 Ⅱ Optic nerve
 Ⅷ Vestibulocochlear nerve
Motor cranial nerves
 Ⅲ Oculomotor nerve
 Ⅳ Trochlear nerve
 Ⅵ Abducent nerve
 Ⅺ Accessory nerve
 Ⅻ Hypoglossal nerve
Mixed cranial nerves
 Ⅴ Trigeminal nerve
 Ⅶ Facial nerve
 Ⅸ Glossopharyngeal nerve
 Ⅹ Vagus nerve

14. TRIGEMINAL NERVE
V cranial nerve.
Largest.
Mixed.
Sensory
root Motor root

15. NUCLEAR CONNECTIONS
Sensory nuclei :
Mesencephalic.
Primary sensory.
Spinal.
Motor nucleus.

16. FUNCTIONAL COMPONENTS
General somatic afferent : Exteroceptive
Proprioceptive
Special visceral efferent : Muscles of first
branchial arch.

17. COURSE
PONS
SENSORY
ROOT
MOTOR
ROOT
TRIGEMINAL
GANGLION
Ophthalmic
branch
(V1)
Maxillary
branch
(V2)
Mandibular
branch
(V3)

18. Sensory root
Motor root
V1
V2
V3

19. BRANCHES
Ophthalmic
Maxillary
Mandibular

20. OPHTHALMIC NERVE (V1)
1st Branch
Sensory
Smallest
Convexity of
Trigeminal Ganglion
Lateral wall of
cavernous sinus
Superior Orbital
fissure
Orbit

21. Branches
LACRIMAL
NASO-
CILIARYFRONTAL

22. Lacrimal nerve
Smallest branch
Communicating branch : Zygomatico-temporal
Provides sensory branches : Lacrimal gland
Conjunctiva
Supplies lateral part of upper eyelid

23. Supra-trochlear : Smaller
• Supplies: conjunctiva and skin of medial aspect
of upper eyelid.
Lower and mesial aspects of forehead.
Supra-orbital : Larger
• Supplies : Upper eyelid
• Skin of the forehead and scalp as far back as
lambdoid suture.
Largest branch
Frontal nerve
Medial branch,
supraorbital
nerve
Supratrochlear
nerve
Frontal nerve
Ophthalmic
nerve
Lateral branch,
supraorbital
nerve

24. Nasociliary nerve
Enters orbit through Superior orbital fissure
Branches
Short ciliary nerves
: sensory fibres from
ciliary ganglion to
eyeball
Long ciliary nerves :
iris and cornea
Infratrochlear nerve :
skin of both
eyelids,adjoining sides
of nose,lacrimal sac
and caruncle
Posterior ethmoidal
nerve : ethmoidal and
sphenoidal sinuses
Anterior ethmoidal
nerve : medial and
lateral internal nasal
branches
Long ciliary
nerves
Infratrochlear
nerve
Short ciliary
nerves
Posterior
ethmoidal
nerve
Anterior
ethmoidal
nerve
Nasociliary
nerves

25. Anterior ethmoidal nerve : continuation of
Nasociliary nerve
Branches : Medial internal nasal
Lateral internal nasal
Lateral internal nasal emerges as External
nasal nerve.
Supplies skin over tip and ala of the nose.

26. MAXILLARY NERVE (V2)
Pre-trematic branch of trigeminal nerve
Sensory
Trigeminal ganglion
Lateral wall of cavernous sinus
Leaves skull through foramen
rotundum
Pterygo-palatine fossa
Inferior orbital infra-orbital
fissure foramen

27. Branches
Middle
cranial
fossa
Ptreygo
palatine
fossa
Infra-
orbital
canal
Face

28. Middle cranial fossa
- Middle meningeal
Pterygo-palatine fossa
1. Zygomatic
zygomaticotemporal (a)
zygomaticofacial (b)
2. Pterygo-palatine
orbital
nasal - nasopalatine (i)
palatine - greater palatine(ii)
- lesser palatine (iii)
pharyngeal
3. Posterior superior alveolar
1
2
3
a
b
i
ii
iii

29. Infraorbital canal
a. Middle superior
alveolar
b. Anterior superior
alveolar
Face
a. Inferior palbebral
b. External nasal
c. Superior labial
MSA
ASA

30. MANDIBULAR NERVE(V3)
Largest branch
Post-trematic nerve of 1st branchial arch
Mixed
Sensory root : Trigeminal
ganglion
Motor root : Pons and Medulla
oblongata
Exit cranium through foramen
ovale
Unite to form the main trunk
After 2-3 mm divides to form
Anterior and Posterior

31. Branches
Main
trunk
PosteriorAnterior

32. Undivided nerve
-Nervous Spinosus
-N. to medial pterygoid
Anterior division
-N. to lateral pterygoid
-N. to masseter
-N. to temporal muscle
-Buccal n.

33. Posterior division
- Auriculotemporal
Auricular
Superficial temporal
Articular
Communicating branches
- Facial nerve
- Otic ganglion
- Lingual
- Inferior alveolar
Mylohyoid
Incisive
Mental
Mylohyoid br.
Inferior alveloar
n.
Lingual n.
Mental n.
Incisive
n.
Mandibular
n.
Auriculo
temporal n.

34. CLINICAL TESTING
Motor system :
Masseter and temporal muscles
Pterygoids.
Sensory system :
Pain, temperature and
light touch in ophthalmic,
maxillary and mandibular
division.
Reflexes :
Corneal reflex
Jaw reflex
V1
V2
V3

35. APPLIED ANATOMY
Trigeminal neuralgia/Tic Douloureux
characterised by extremely severe lancinating
pain that occurs in paroxysms, limited to one or
more branches of Trigeminal n.
Etiology: Idiopathic
Vascular
compression
Progressive
degeneration
Intra-cranial
tumor
Peripheral nerve
injury

36. Clinical features:
- Older adults, Female predilection
- Right side affected more
- Intense shooting stabbing pain
- Electric shock-like
- Unilateral
- Maxillary > Mandibular > Ophthalmic
- Trigger zone
- Spasmodic contraction of facial muscle

37. Treatment : Carbamazepine
• Cryosurgery
• Peripheral neurotomy
Peripheral
nerve
• 1.Percutaneous radiofrequency
thermo-coagulation
• 2.Glycerol injection
• 3. Balloon microcompression
Gasserian
ganglion
• Microvascular decompression of
nerve rootBrainstem

38. Frey’s syndrome
Damage to auriculotemporal nerve &
subsequent reinnervation of sweat glands.
Clinical features :
Flushing & sweating on
the involved side of the face
Treatment : Botulinum toxin
injections
Resection of
nerve

42. CONTENTS
Introduction.
Organization of Nervous System.
Related Terminologies.
Cranial Nerves.
Detailed study of
V. Trigeminal nerve
VII. Facial nerve
IX. Glossopharyngeal nerve
X. Vagus nerve
XII. Hypoglossal nerve
References.

44. FACIAL NERVE
VII Cranial nerve
Mixed
Sensory component: Nervus intermedius of
Wrisberg
Nerve of 2nd branchial arch

45. NUCLEAR CONNECTIONS
Motor nucleus
Superior salivatory nucleus
Lacrimatory nucleus
Nucleus of tractus solitarius

46. coMotor nucleus
Upper part of face :
Cortico-nuclear fibres
from motor cortex of
both sides.
Lower part of face:
Cortico-nuclear fibres
from opposite
cerebral hemisphere.
CENTRAL CONNECTIONS

47. FUNCTIONAL COMPONENTS
Special visceral efferent*
muscles of 2nd branchial arch
General visceral efferent*
secretomotor
Special visceral afferent*
taste sensation from
anterior 2/3rd of tongue
and palate
General somatic afferent*
part of skin of the ear

48. COURSE
The course of the nerve can be explained as :
• Intracranial course
• Extracranial course

49. INTRACRANIAL

50. EXTRACRANIAL
Superficial to styloid
process
Pierces surface of parotid
gland
Runs forward
Temporo-facial and Cervico-facial trunks
Divides into 5 branches – ‘pes anserinus’

51. BRANCHES
FACIAL
CANAL
FACE
BELOW
STYLO-
MASTOID
FORAMEN

52. Facial canal 1. Greater petrosal
n.
2. N. to stapedius
3. Chorda tympani n.
Below stylomastoid foramen 1. Posterior Auricular
2. N. to Post. Belly of
diagastric
3. N. to Stylohyoid
Face 1. Temporal
2. Zygomatic
3. Buccal
4. Marginal
mandibular
5. Cervical

53. CLINICAL TESTING
Motor function : Ask the patient to raise
eyebrows, wrinkle, close eyes tightly, show teeth,
blow out cheek, whistle.
Sensory function : Sweet, salty, sour, bitter
taste.
Secretory function : Lacrimation
- Schirmer’s test
- Nasolacrimal reflex
Salivation
Reflexes : Corneal reflex
Stapedial reflex

54. APPLIED ANATOMY
Supranuclear paralysis
Nuclear paralysis
Infranuclear paralysis

55. Nuclear Supranuclear

56. Infranuclear paralysis : according to site of
involvement :
1. Below stylo-
mastoid foramen
2. Facial canal
3. Genu
4. Internal acoustic
meatus
3 4
2
1

57. BELL’S PALSY
Idiopathic unilateral lower motor neuron paralysis
of sudden onset.
Sir Charles Bell
Etiology :
Inflammation or
compression
Symptoms

58. TREATMENT
No standard course of treatment –
symptomatic treatment
Steroids - prednisolone 1mg/kg body wt for
10-14 days with a gradual tapering
Anti-viral drug
Analgesics
Eye protection

60. GLOSSOPHARYNGEAL NERVE
IX cranial nerve
Mixed
Post-trematic branch of 3rd branchial arch
Ganglia
• Detached part of
inferior ganglion
• No branches
Superior
• Larger
Inferior

61. NUCLEAR CONNECTIONS
Nucleus ambiguus
Inferior salivatory nucleus
Spinal nucleus of trigeminal nerve
Nucleus of tractus solitarius

62. FUNCTIONAL COMPONENTS
Special visceral efferent : stylopharyngeus
muscle.
General visceral efferent : from inferior
salivatory nucleus to otic ganglion, the
postganglionic fibers supply parotid gland
General visceral afferent : pharynx, posterior
part of the tongue, carotid sinus, carotid body
Special visceral afferent : posterior 1/3rd of
tongue, circumvalate papillae
General somatic afferent : posterior 1/3rd of
tongue, tonsils, soft palate, oral part of
pharynx

63. SVE
GVE
AFFERENT

64. COURSE
3-4 rootlets
Medulla oblongata
Root trunk
Presents 2 ganglia
Jugular foramen

65. Internal jugular vein and
Internal carotid artery
Internal and External
carotid arteries
Side of the pharynx
Submandibular region
Tonsillar Lingual

66. BRANCHES
Tympanic
Carotid
Pharyngeal
Muscular
Tonsillar
Lingual

67. CLINICAL TESTING
Gag reflex
Taste sensation

68. APPLIED ANATOMY
GLOSSOPHARYNGEAL NEURALGIA
Rare
Paroxysmal pain
Trigger zone
May be associated with vagal symptoms
Etiology : Tumours and vascular abnormalities
Treatment :
Carbamazepine
Surgical section of nerve
Percutaneous radiofrequency thermocoagulation
Microvascular decompression

70. VAGUS NERVE
X cranial nerve
Extensive (vague)
course
3 parts- Cervical
Thoracic
Abdominal
Cervical part presents 2 ganglia
Inferior Superior

71. NUCLEAR CONNECTIONS
Nucleus ambiguus
Dorsal nucleus of the vagus
Nucleus of tractus solitarius
Nucleus of the spinal nerve

72. FUNCTIONAL COMPONENTS
Special visceral efferent : muscles of palate,
pharynx & larynx
General visceral efferent : thoracic &
abdominal viscera.
General visceral afferent : sensations from
pharynx, larynx, trachea, oesophagus and
abdominal & thoracic viscera
Special visceral afferent : sensation of taste
from the posterior most part of the tongue &
epiglottis
General somatic afferent : skin of the
external ear

73. COURSE
Medulla oblongata
Jugular foramen
Carotid Sheath
Root of the neck
Right/Left Vagus

74. COURSE
Coeliac
plexus
Pulmonary plexus
Oesophageal plexus
Hepatic
Gastric

75. BRANCHES
Jugular
foramen
Abdomen
Thorax
Neck

76. BRANCHES
JUGULAR FORAMEN
Meningeal
Auricular
NECK
Pharyngeal branches
Superior laryngeal
Branches to carotid body
Cardiac branches
Right recurrent laryngeal
THORAX
Cardiac
Left recurrent laryngeal
Pulmonary
Oesophageal
ABDOMEN
Gastric
Coelic
Hepatic

77. CLINICAL TESTING
General sensation and Taste sensation
Palatal reflex
Gag reflex

78. APPLIED ANATOMY
Paralysis of vagus nerve
Irritation of recurrent laryngeal nerve
Irritation of auricular branch in external ear
Low grade stimulation of the auricular branch

80. HYPOGLOSSAL NERVE
XII cranial nerve
Motor
Supplies all muscles of the tongue, except
palatoglossus muscle

81. NUCLEAR CONNECTIONS
Hypoglossal nucleus: elongated nucleus
Functional components:
General somatic efferent

82. COURSE
10- 15 rootlets through medulla oblongata
Two bundles
Pierce dura mater
Lower part of the canal – single nerve trunk
Hypoglossal canal
Between internal jugular vein and internal carotid artery
Carotid triangle

83. COURSE
Digastric triangle
Rests on hyoglossus muscle
Deep to mylohyiod muscle
Pierces genioglossus
Substance of the tongue

84. BRANCHES
Meningeal branch
Descending branch
Nerve to thyrohyoid and geniohyoid muscles
Muscular branches

85. CLINICAL TESTING
Patient asked to put out his tongue
Check for :
- deviation
- abnormal movement
- strength
- wasting, tremor, fibrillation

86. APPLIED ANATOMY
UPPER
MOTOR
NEURON
LESION
LOWER
MOTOR
NEURON
LESION

87. CONCLUSION
A clinicians’ thorough understanding of the
anatomy of the cranial nerves and its clinical
applications is essential for treatment planning
as well as avoiding any untoward complications
while treating the patients.

88. REFERENCES
1. Human anatomy BD Chaurasia. Vol 3, 4th edition
2. Grays anatomy 39th edition
3. Clinical neuroanatomy, Richard S. Snell 6th edition
4. Essentials of Human Anatomy-Head & neck, A K Dutta 3rd edition
5. A Regional Atlas of the human body, Clemente
6. Shafer’s text book of oral pathology 5th edition
7. Handbook Of Local Anaesthesia, Malamed 5th edition
8. Medicine for dental students, Allagapan 1st edition
9. Burkets Oral medicine-10th edition

90. XII COURSE
10- 15 rootlets emerge through medulla oblongata
Runs laterally
Joins to form 2 bundles
Each pierce dura mater separately
Lower part of the canal –unite to form a single nerve trunk
Leaves skull through hypoglossal canal
Passes vertically downward between internal jugular vein
and internal carotid artey
Appears in carotid triangle
Passes forward to appear in the diagastric triangle
Rests on hyoglossus muscle,deep to deep part of
submandibualr gland,submandibular ganglion and lingual
nerve
Passes deep to mylohyiod muscle,pierces genioglossus
Reaches substance of the tongue

91. Right vagus
Passes downward
right posterior pulmonary
plexus
oesophageal plexus
posterior vagal trunk
gastric coeliac

92. Left vagus
Passes downward
Left posterior pulmonary
plexus
Anterior vagal trunk
gastric hepatic