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
Position of nucleus
Emerging point from brain stem
Intracranial course
Point of exit from the cranial cavity
Extracranial course
Distribution

4. Few terms: Somatic, branchial and visceral

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

6. Mandibular branch of trigeminal nerve (V)
Facial nerve (VII)
Premaxilla, maxilla, zygomatic bone, part of temporal bone and mandible
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
Somatic sensory
Visceral sensory
Motor
Sensory
Visceral motor
Somatic motor
Spinal cord (thoracic or lumbar)
Posterior horn
Lateral horn
Anterior horn
Motor
Sensory

10. Brain stem
SpS
GSS SS VS VM BM SM

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

12. SpS SS VS BM SM VM
SpS SS VS BM SM VM

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

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

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

16. 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)

17. Sensory Visceral sensory with taste
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

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

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

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

21. Intracranial course and exit
Sanjaya Adikari
Department of Anatomy

24. Optic canal
(II)
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)

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

26. Optic Nerve (II) T N

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

28. 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

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

30. 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

31. 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

32. Oculomotor N (III) Trochlear N (IV) Abducent N (VI) Ventral midbrain
Lateral wall
Cavernous S
Divide
Sup. & Inf.
divisions
Sup/infraorbital 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

33. 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

34. LR6(SO4)3

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

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

37. Facial Nerve (VII) Visceral motor nucleus (Superior salivary nucleus)
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

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

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

40. 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

41. 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

42. Accessory Nerve (XI) Branchial motor nerve Somatic 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 cervical spinal segments
Fibres in the spinal root supply sternocleidomastoid and trapezius muscles

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

46. GSA VE BE BA

47. GSA BE BA VE