1. III,IV & VI Cranial Nerves
By.
Dr Rakesh Kumar Verma
Assistant Professor
Anatomy
KGMU,UP, Lucknow

2. Oculomotor (III) cranial nerve (nervus oculomotorius)

3. Functional Component General Somatic Efferent (GSE)
General Visceral Efferent (GVE)
General Somatic Afferent (GSE)

4. Oculomotor nerve (nervus oculomotorius)
contains motor and vegetative (parasympathetic) fibers
Type of fibers
Beginning
End
1. Motor fibers
Neurons contained in the oculomotor nerve nucleus (situated in the midbrain)
Innervated extraocular muscles
Neurons contained in the central nucleus of Perlia (situated in the midbrain)
2. Parasympathetic nucleus
Neurons contained in the accessory oculomotor nerve nucleus (of Edinger-Westphal) (situated in the midbrain)
Innervated intraocular muscles

5. Topography of the oculomotor nerve
nuclei and root

6. Location of oculomotor nerve nuclei
Oculomotor nerve nucleus
(nucleus nervi oculomotorii)
Accessory oculomotor nerve nucleus
(nucleus acceccorius
nervi oculomotorii)
(nucleus of Edinger-Westphal)

7. Location of oculomotor nerve nuclei in midbrain cross-section
Central nucleus of Perlia
(nucleus centralis impar)
Oculomotor nerve nucleus
(nucleus nervi oculomotorii)
Accessory nucleus
(nucleus acceccorius
nervi oculomotorii)
(of Edinger-Westphal)

8. Oculomotor nerve emerges in the oculomotor sulcus
at the region of the interpeduncular fossa

9. Course of oculomotor nerve

10. The course of the oculomotor nerve before the entrance the orbit
Superior orbital fissure
(fissura orbitalis superior)
Central nucleus of Perlia
(nucleus centralis impar)
Superior branch (motor)
(ramus superior)
Parasympathetic fibers
of oculomotor nerve
Motor fibers
to the medial rectus
Accessory nucleus
(nucleus accessorius
nervi oculomotori)
(of Edinger-Westphal)
Motor fibers to other
extraocular muscles
Oculomotor nerve nucleus
(nucleus nervi oculomotori)
Inferior branch (mixed)
(ramus inferior)
Cavernous sinus
(sinus cavernosus)

11. The course of the motor fibres of the oculomotor nerve in the orbit
Levator palpebrae superioris
Superior branch of oculomotor nerve
(ramus superior)
Superior rectus
Medial rectus
Inferior branch of oculomotor nerve
(ramus inferior)
Inferior rectus
Inferior obliquus

12. Location of oculomotor nerve in the orbit
Superior orbital fissure
(fissura orbitalis superior)
Superior branch of oculomotor nerve
(ramus superior)
Levator palpebrae superioris
Superior rectus
Medial rectus
Inferior rectus
Inferior obliquus
Inferior branch of oculomotor nerve
(ramus inferior)

13. The course of the parasympathetic fibres in the orbit
Ciliary muscle
(musculus ciliaris)
Preganglionic fibers
Musculus
sphincter pupillae
Ciliary ganglion
(ganglion ciliare)
Postganglionic fibers
(short ciliary nerves)
(nervi ciliares breves)

14. The ocular muscles innervated by the oculomotor nerve
I. Motor fibers innervate:
1. Levator palpebrae superioris
2. Superior rectus
3. Medial rectus
4. Inferior rectus
5. Inferior obliquus
II. Parasympathetic fibers innervate:
1. Ciliary muscle
2. Sphincter of pupil

15. Symptoms of oculomotor nerve injury

16. The damage to the nucleus, root or trunk of the oculomotor nerve leads to the following symptoms :
Ptosis (falling) of the upper eyelid because of paralysis or paresis of
the levator palpebrae superioris

17. 2. Divergent strobismus – the eyeball is inclined outwards and slightly downwards due to predominance of the functioning of the superior oblique and lateral rectus muscle
3. Mydriasis (dilation of pupil) on the injured side due to predominance of the pupillary sphincter functioning; the pupillary light reflex is absent on the injured side

18. 4. Horizontal diplopia – appearance of two images in the horizontal plane; it increases if to look to the side of the injured medial rectus and disappears if look only with one eye.
5. The movements of the eye upwards and inwards are limited; the eyeball can not converge
7. Paralysis of accomodation due to the damage to the ciliary muscle
8. Small exophthalmos due to the decrease of the muscle tone

19. Trochlear (IV) cranial nerve
(nervus trochlearis)

20. Functional Component General Somatic Efferent (GSE)
General Somatic Afferent (GSE)

21. Trochlear nerve (nervus trochlearis)
is fully motor
Type of fibers
Beginning
End
Motor fibers
Neurons contained in the trochlear nerve nucleus (situated in the midbrain)
Superior oblique muscle of eyeball

22. Topography of the trochlear nerve
nucleus and root

23. Location of the trochlear nerve nucleus
(nucleus nervi trochlearis)

24. Location of the trochlear nerve nucleus
in the cross-section of the midbrain
Trochlear nerve nucleus
(nucleus nervi trochlearis)

25. Trochlear nerve (nervus trochlearis)
emerges on the dorsal surface of the midbrain, lateral to the frenulum of the superior medullary velum; then the nerve skirts the cerebral peduncle from the lateral side and appears on the cerebral base (the trochlear nerve is a single cranial nerve which emerges on the dorsal surface of the brain steam)

26. The course of the trochlear nerve

27. The course of the trochlear nerve before entering the orbit
Superior orbital fissure
(fissura orbitalis superior)
Trochlear nerve
Trochlear nerve nucleus
(nucleus nervi trochlearis)
Cavernous sinus
(sinus cavernosus)

28. The course of the trochlear nerve in the orbit Superior oblique muslce
(nervus trochlearis)

29. Location of the trochlear nerve in the orbit
Superior orbital fissure
(fissura orbitalis superior)
Trochlear nerve
(nervus trochlearis)
Levator palpebrae superioris
Supeior rectus muscle
Superior oblique muscle
Medial rectus muscle
Inferior rectus muscle
Inferior oblique muscle

30. The trochlear nerve innervates
Superior oblique muscle of eye

31. Symptoms of the trochlear nerve injury

32. The damage to the nucleus, root or trunk of the trochlear nerve leads to the following symptoms:
1. Convergent strabismus - the eyeball is turned inwards and slightly upwards due to the disorder of the superior oblique muscle innervation; it increases if to look down.
2. Vertical diplopia – appearance of two images in the vertical plane, especially if to look down. During bending of the head to the side of the injured muscle, diplopia increases; to the opposite side – decreases.

33. Abducent (VI) cranial nerve
(nervus abducens)

34. Functional Component General Somatic Efferent (GSE)
General Somatic Afferent (GSE)

35. Abducent nerve (nervus abducens)
is fully motor
Type of fibers
Beginning
End
Motor fibers
Neurons contained in the abducent nerve nucleus (situated in the pons)
Lateral rectus muscle of eye

36. Topography of the abducent nerve
nucleus and root

37. Location of the abducent nerve nucleus
(nucleus nervi abducentis)
is arched by the curve of the facial nerve fibers
(genu nervi facialis)
in the facial colliculus
of the rhomboid fossa

38. Location of the abducent nerve nucleus
in the cross-section of the pons
Abducent nerve nucleus
(nucleus nervi abducentis)

39. Abducent nerve (nervus abducens)
Emerges in a transverse pontomedullary groove between the pons
and pyramids of the medulla oblongata

40. The course of the abducent nerve

41. The course of the abducent nerve before the entering the orbit
Superior orbital fissure
(fissura orbitalis superior)
Abducent nerve
Abducent nerve nucleus
(nucleus nervi abducentis)
Cavernous sinus
(sinus cavernosus)

42. The course of the abducent nerve in the orbit
(nervus abducens)
Lateral rectus muscle
(has been cut)

43. Location of the abducent nerve in the orbit
Superior orbital fissure
(fissura orbitalis superior)
Levator palpebrae superioris
Superior rectus muscle
Superior oblique muscle
Abducent nerve
(nervus abducens)
Lateral rectus muscle
Medial rectus muscle
Inferior rectus muscle
Inferior oblique muscle

44. The abducent nerve innervates
Lateral rectus muscle of the eye

45. Symptoms of the abducent nerve injury

46. The damage to the nucleus, root or trunk of the abducent nerve leads to the following symptoms :
1. Convergent strabismus - the eyeball is turned inwards due to disorder of the lateral rectus muscle innervation.
2. Horizontal diplopia – appearance of two images in the horizontal plane if to look to the injured side.

47. the III, IV, VI cranial nerves
Topography of
the III, IV, VI cranial nerves

48. Location of the nuclei of the III, IV and VI cranial nerves
Trochlear nerve nucleus
(nucleus nervi trochlearis)
Accessory nucleus of
oculomotor nerve
(nucleus accessorius
nervi oculomotorii)
(of Edinger-Westphal)
Abducent nerve nucleus
(nucleus nervi abducentis)
Oculomotor nerve nucleus
(nucleus nervi oculomotorii)

49. Location of the branches of the III, IV and VI
cranial nerves in the orbit
Trochlear nerve
(nervus trochlearis)
Superior branch of
oculomotor nerve
(ramus superior)
Short ciliary nerves
(nervi ciliares breves)
Abducent nerve
(nervus abducens)
Inferior branch of
oculomotor nerve
(ramus inferior)
Ciliary ganglion
(ganglion ciliare)

50. Location of the branches of the III, IV and VI
cranial nerves in the orbit
Superior branch of
oculomotor nerve
(ramus superior)
Trochlear nerve
(nervus trochlearis)
Inferior branch of
oculomotor nerve
(ramus inferior)
Abducent nerve
(nervus abducens)