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1. Cranial Nerves
Sanjaya Adikari
Department of Anatomy

2. 12 pairs of cranial nerves
III to XII attached to
brain stem
Their cell bodies form
nuclei in the brain stem
First cell body of sensory
nerves lie out side CNS
(form ganglia)

3. Summary of cranial nerves
Aspects to study
1. Position of nucleus
2. Emerging point from brain stem
3. Intracranial course
4. Point of exit from the cranial cavity
5. Extracranial course
6. Distribution

4. Few terms: Somatic, branchial and visceral

5. Branchial (Pharyngeal) Arches
• Core of mesodermal
tissue covered by
ectoderm and
endoderm
• Each of the arch will
have its own
bone/cartilage, muscles,
nerve and artery
endoderm
ectoderm
Branchial

6. Premaxilla, maxilla, zygomatic
bone, part of temporal bone and
mandible
Mandibular branch of
trigeminal nerve (V)
Facial nerve (VII)
Glossopharyngeal nerve
(IX)
Superior laryngeal branch
of vagus nerve (X)
Recurrent laryngeal branch
of vagus nerve (X)

7. Visceral
• In relation to internal organs
– Heart
– Lung
– Intestines
………………
……………..

8. Few hints
Nerve A
Nerve B

9. Posterior horn
Lateral horn
Anterior horn
Motor
Sensory
Motor
Sensory
Posterior
Spinal cord (thoracic or lumbar)
Somatic sensory
Visceral sensory
Visceral motor
Somatic motor

10. SM
VM
VS
BM
SS
Brain stem
SpS
GSS

11. Types of sensations
Visceral sensory
Somatic sensory
General Visceral sensory
pain, temperature, touch, viration
position sense
Special Visceral sensory
taste
General Somatic sensory
pain, temperature, touch, vibration
position sense
Special Somatic sensory
hearing

12. SM
VS
GSS
SS
III
IV
VI
XII
BM
V
VII
IX
X
XI
VM
III
VII
IX
X
VII
IX
X
V
VII
IX
X
VIII

13. Functional components of cranial nerves
Somatic Motor
Muscles of the orbit
(III, IV, VI)
Muscles of tongue
(XII)
III
IV
VI
XII

14. Branchial Motor
Muscles of mastication (V)
Facial muscles (VII)
Pharyngeal and laryngeal
muscles (Nucleus ambiguus
via IX, X, XI nerves)

15. Visceral Motor
Edinger Westphal nucleus
(accessory oculomotor)
Salivary nuclei (NI part of VII, IX)
Dorsal motor nucleus of vagus
(for cardiac muscles, smooth
muscles of alimentary tract)

16. Sensory
Consists of single nuclei for visceral
and somatic sensory
Visceral sensory with taste
Nucleus of tractus solitarious which
receives taste fibres from the tongue
through VII, IX
and sensory from heart, lungs and
other viscera through X

17. General somatic sensory
Sensory nucleus of trigeminal
nerve extending from the
midbrain to the cervical spinal
cord

18. Special somatic sensory
Hearing via VIII
(vestibulocochlear nerve)

19. SM VM
VS
BM
GSS
SS
V
VII
IX
X
XI
III
IV
VI
XII
III
VII
IX
X
VII
IX
X
V
VII
IX
X
VIII

20. Intracranial course and exit
Sanjaya Adikari
Department of Anatomy

22. Superior orbital fissure
(III, IV, V1, VI)
Foramen rotundum
(V2)
Foramen ovale
(V3)
Foramen spinosum
Foramen lacerum
Internal acoustic meatus
(VII, VIII)
Jugular foramen
(IX, X, XI)
Hypoglossal canal
(XII)
Optic canal
(II)

23. Olfactory Nerve (I)
Olfactory bulb
Olfactory tract
Anterior perforated
substance
Uncus
Bypass thalamus and goes directly into
the taste area
Nerve filaments
Cribriform plate of
ethmoid bone

24. Optic Nerve (II)
T
N
T

25. Optic Nerve (II)
Optic nerve
Optic chiasma
Optic tract
Superior colliculus
(body reflexes)
Pretectal nucleus
(pupillary reflexes)
Lateral geniculate body
of thalamus
Internal
capsule
Optic
radiation

26. Oculomotor Nerve (III)
Somatic motor nucleus
Visceral motor nucleus
(Edinger westphal nucleus)
Nerve emerges from ventral
aspect of midbrain
travel’s in the lateral wall of the
cavernous sinus

27. Oculomotor Nerve… cont.
Levator palpabrae
superioris
Dilator pupillae
Superior rectus
Medial rectus, inferior
rectus, inferior oblique
Ciliary muscle
Sphincter pupillae
Ciliary ganglion
Superior division
Inferior division
Sympathetic from
Internal carotid plexus
Parasympathetic from
EW nucleus

28. Trochlear Nerve (IV)
Somatic motor nucleus
Emerges from the dorsal aspect of
midbrain
Travels in the lateral wall of the
cavernous sinus
Supplies the superior oblique muscle

29. Abducens Nerve (VI)
Somatic motor nucleus
Nucleus lies in lower pons near
midline
Emerge between pons and pyramid
of medulla
Travels through the cavernous sinus
Supply the lateral rectus muscle

30. Oculomotor N (III)
Ventral
midbrain
Lateral wall
Cavernous S
Divide
Sup. & Inf.
divisions
Sup/infrao
rbital
fissure
Trochlear N (IV)
Dorsal
midbrain
Lateral wall
Cavernous S
Superior
orbital
fissure
Abducent N (VI)
Between
Pons & pyramid
of medulla
within
Cavernous S
Superior
orbital
fissure

31. Cavernous sinus
1- Oculomotor N
2- Trochlear N
3- Abducent N
4- Ophthalmic branch of TN
5- Maxillary branch of TN
6- Sympathetic plexus of N
7- Internal carotid A
8- Pituitary gland

32. LR6(SO4)3

33. Trigeminal nerve (V)
Branchial motor nucleus
Somatic sensory nucleus
Emerge from the ventral aspect of pons
Sensory and motor roots emerge
separately

34. Trigeminal nerve… cont.
Cell bodies of 1st order
SA fibres
Trigeminal ganglion
Somatic
sensory
nucleus
Branchial
motor
nucleus
Foramen ovale
Ophthalmic
division
Maxillary
division
Lat. Wall of
cavernous
sinous
Mandibular
division
Mandibular
nerve
(mixed)

35. Facial Nerve (VII)
Branchial motor nucleus
Visceral motor nucleus
(Superior salivary nucleus)
Taste sensory nucleus
(Tractus solitarius)
Main facial nerve and the
nervous intermedius parts
emerge from the
cerebellopontine angle

36. Geniculate ganglion
(taste 1st order cell bodies)
Nucleus of
Tractus
solitarious
Chorda tympani
nerve
Taste from
anterior tongue
Nervous
intermedius
Facial Nerve…cont.
Branchial motor
nucleus
Nerve to
stapedius
Stylomastoid
foramen
Pure branchial motor facial nerve
Supply muscles of facial
expression
Ear drum
VE to submandibular gland
and glands on the mouth floor
Greater petrosal
nerve
Sup. salivary
nucleus
Internal acoustic
meatus

37. Vestibulocochlear Nerve (VIII)
Cochlear nerve
Vestibular nerve
Hair cells of spiral
organ
Hair cells of utricle,
saccule and semilunar
canals
Spiral ganglion of cochlea
Vestibular ganglion
Internal acoustic
meatus
Cerebellopontine
angle
Cochlear
nuclei
in pons
Vestibular
nuclei
in medulla

38. Glossopharyngeal Nerve (IX)
Branchial motor nucleus (Nucleus ambiguus)
supplies stylopharyngeus muscle
Parasympathetic nucleus (Inferior salivary
nucleus)
supplies parotid gland
Sensory nuclei
GSS from posterior tongue goes to sensory
nucleus of trigeminal nerve
Taste from the posterior tongue goes to the
tractus solitarius
VS from baroreceptors go to nucleus of tractus
solitarius

39. Vagus Nerve (X)
Branchial motor nucleus (Nucleus ambiguus)
supplies pharyngeal constrictors
Visceral motor nucleus (Dorsal motor nucleus
of vagus)
supplies muscles of heart, bronchi, oesophagus,
stomach and intestines
Visceral sensory nucleus
VS from larynx, heart, lung… goes to nucleus of
tractus solitarius
GSS goes to sensory nucleus of trigeminal nerve

40. Accessory Nerve (XI)
Branchial motor nerve
Cranial root From nucleus ambiguus
Fibres in the cranial root join the vagus
nerve
Somatic motor nerve
Spinal root Anterior horn cells of upper 5-6
cervical spinal segments
Fibres in the spinal root supply
sternocleidomastoid and trapezius
muscles

41. Hypoglossal Nerve (XII)
Somatic motor nerve
Leaves cranial cavity through the hypoglossal canal
Supplies all muscles (intrinsic and extrinsic) of tongue except
palatoglossus