from our department (Al Azhar university)grand round

1. بسم الله الرحمن الرحيم

2. Anatomy of ocular cranial nerves

3. Ocular cranial nerves
Motor nerves
Oculomotor nerve
Trochlear nerve
Abducent nerve
Mixed motor and sensory nerves
Trigeminal nerve
Facial nerve
Visual system
Optic nerve & visual pathway

4. Oculomotor nerve
(3rd)

5. Nuclei of origin: (at the upper level of mid
brain)
Nuclear complex:
Site:
In the midbrain at the level of the superior
colliculus
Ventral to the Sylvain aqueduct

6. • Levator subnucleus
Unpaired
Innervates both levator muscles
• Superior rectus subnuclei
Paired
Innervates the contralateral superior rectus
• Medial rectus, inferior rectus & inferior oblique
subnuclei
Paired
Innervate the ipsilateral muscles
Edinger-Westphal:
Paired
Give preganglionic parasympathetic -- ciliary ganglion.

8. Course and parts:
Fasciculus
Third nerve nucleus (Efferent fibers)
pass through the red nucleus----substantia nigra ---
emerge at the medial aspect of the cerebral peduncle ---
 interpeduncular fossa.
Basilar part
Starts as a series of rootlets which leave the midbrain on
the medial aspect of the cerebral peduncle --- coalesce
to form the main trunk
Passes between posterior cerebral a. & superior
cerebellar a.
Running lateral to and parallel with the posterior
communicating a.

10. Intercavernous part
Third nerve enter the cavernous sinus and runs in
the lateral wall above the 4th nerve.
Divides in the anterior part of cavernous into
superior and inferior branches which enter the orbit
through the SOF within the annulus of Zinn.
Intraorbital part
Superior division---levator palpebrae superiosis &
superior rectus.
Inferior division---medial rectus, inferior rectus &
inferior oblique.

12. Parasympathetic preganglionic fibers---
pass with n. to inf.oblique
---Ciliary ganglion ----short ciliary nerves---
constrictor muscle + ciliary muscle.
Sympathetic postganglionic
fibers---pass with n. to levator palpebrae
superiosis---Muller muscle

13. Trochlear nerve
(4th)

14. Nucleus
Site: In the midbrain at the level of the inferior
colliculus.
Ventral to the Sylvain aqueduct
It is caudal to, and continuous with the 3rd nerve
nuclear complex.

15. Course and parts
Fasciculus
Consists of axons which curve posteriorly & decussate
around the cerebral aqueduct in the anterior medullary
velum.
The trunk
It leave the brainstem on the dorsal surface just caudal to
the inferior colliculus --- curve laterally around the
brainstem--- runs forwards under the free edge of the
tentorium--- pass between the posterior cerebral artery &
the superior cerebellar artery.

17. Intracavernous part
The 4th nerve enters the cavernous sinus and runs in
the lateral wall inferior to the 3rd nerve and above the
1st division of the 5th.
In the inferior part of the cavernous sinus it rises and
passes through SOF above and lateral to the annulus of
Zinn.
Intraorbital part
It passes anteriorly and medially crossing above the
Oculomotor nerve, levator palpebral superiors muscle
and the superior rectus muscle
It enters the superior oblique muscle on its orbital
surface.

19. Abducent nerve

20. Nucleus
Site: at the lower level of the pons.
Ventral to the floor of the 4th ventricle.
The fasciculus of 7th nerve curve around the
Abducent nucleus and produce an elevation in
the floor of the 4th ventricle (facial colliculus).

22. Course and parts
Fasciculus
Passes ventrally to leave the brainstem at the ponto
medullary junction.
Basilar part
• Passes upward close to the base of the skull.
• Crossed by the anterior inferior cerebellar artery.
• Pierces the dura below the posterior clinoid.
• Crosses the apex of petrous bone.
• Enter the cavernous sinus.

23. Intracavernous part
Runs forwards inferolateral to I.C.A. at the lower
level than 3rd & 4th nerves, as well as the
ophthalmic n.
Intraorbital part
SOF within the annulus of Zinn (between the two
heads of the LR muscle) --- lateral rectus muscle
through its bulbar surface.

25. The trigeminal nerve

26. The trigeminal nerve has two roots, sensory and
motor, and has a ganglion
Origin:
The two roots arise from
the lateral border of the pons.
Course:
On emerging from brainstem --- push the dura at
apex of petrous bone ---- forming a dural the
pocket called Cavum Trigeminal.

27. Trigeminal ganglion
• Crescent-shaped mass of cells
• Lying in the trigeminal impression on the
anterosuperior surface of petrous bone.
• Enclosed inside cavum trigeminal.
• It has 2 borders:
Posterior concave border ---- attached to sensory root.
Anterior convex border ---- attached to ophthalmic,
maxillary & mandibular nerves.

29. The ophthalmic nerve
Course:
• It start at the trigeminal ganglion --- passes
forward in the lateral wall of the cavernous sinus
• Just posterior to SOF, it receives the frontal,
lacrimal, and nasociliary nerves
• The frontal and lacrimal nerves leave the orbit
above the ligament of Zinn, while the nasociliary
leaves through the annulus of the ligament.

31. Frontal nerve
• The largest
• Runs over Levator palpebrae superiosis.
• Branches:
Supra trochlear n. --- sensory from the medial
scalp, eyelid and conjunctiva.
Supra orbital n. --- sensory from the forehead,
scalp & upper eyelid.

32. Nasociliary nerve
• Medium sized
• Passes forward and medially (with the ophthalmic a.)
crossing over optic n.
• Branches:
 Sensory root to ciliary ganglion.
 2 long ciliary nerves --- sensory to the globe +
sympathetic to dilator ms.
 Posterior ethmoidal n.
 Anterior ethmoidal n.
 Infratrochlear n. --- superior and inferior palpebral
nerves.

33. Lacrimal nerve
The smallest.
Runs over the upper border of LR (with lacrimal a.)
Branches:
 Superior branch (the lateral palpebral nerve) ---
sensory from the skin and conjunctiva of the upper
and lower eyelids.
 Inferior branch
Sensory supply to lacrimal gland.
Secretory to lacrimal gland.

34. The maxillary nerve
Course:
It start at the trigeminal ganglion --- pass forward in
the lateral wall of the cavernous sinus --- foramen
rotundum --- ptrego palatine fossa --- infratemporal
fossa --- inferior orbital fissure --- continuous as
infra orbital nerve .
 It has 2 terminal branches:
Infraorbital nerve & Zygomatic nerve

36. Infraorbital nerve:
It runs forwards from the inferior orbital fissure to --
- infraorbital groove --- infraorbital canal ---
infraorbital foramen
Branches:
• Middle superior alveolar n.
• Anterior superior alveolar n.
• Terminal ( Nasal , Labial , Palpebral )
The palpebral branch supply the skin and
conjunctiva of lower lid.

37. Zygomatic nerve
It is divided into:
Zygomatico temporal and Zygomatico facial
nerve
Zygomatico temporal nerve:
It runs in a groove on the lateral wall of orbit.
It gives a communicating branch to the lacrimal
nerve which carries parasympathetic secretory
fibers to the lacrimal gland.

38. Facial nerve

39. Nuclei of origin:
Facial motor nucleus:
• Located in the lower pons
• Supplies the 2nd brachial arch.
Nucleus solitaries:
• Located in the medulla.
• Receives taste from anterior 2/3 of tongue.

40. Parasympathetic nuclei:
Lacrimatory nucleus --- parasympathetic
preganglionic fibers to sphenopalatine ganglion ---
lacrimal gland
It receives afferent fibers from hypothalamus (for
emotional response) & from the sensory nuclei of the
trigeminal nerve (for reflex lacrimation to irritation of
the cornea or conjunctiva).

41. Course:
In the brain stem
It has 2 roots:
Motor root & nervus intermedius.
Both roots emerge from the brain stem at the inferior
border of the pons, lateral to the Abducent nerve.
Intracranial & extracranial course
On emerge from the brain stem --- pass in the
posterior cranial fossa --- internal auditory meatus ---
facial canal.

42. In the facial canal
Runs above the inner ear.
Descend behind the middle ear --- stylomastoid
foramen.
Below the stylomastoid foramen:
The nerve turns anteriorly around the base of
the styloid process to enter the parotid gland,
where it divide into its terminal branches.

44. Branches:
In the facial canal:
 Greater petrosal nerve :
• From geniculate ganglion
• Ptregopalatine fossa
• Sphenopalatine ganglion (relay) --- postganglionic
parasympathetic fibers --- join maxillary n. ---
Zygomatico temporal n. --- lacrimal n. --- lacrimal
gland.
 Nerve to Stapedius.
 Chorda Tympani

45. Below the stylomastoid foramen:
 Nerve to posterior belly of Digastric.
 Nerve to stylohyoid.
 Posterior auricular nerve.
 Terminal branches (inside the parotid)
 Upper temporofacial --- temporal and zygomatic
branches ( supplying the orbicularis oculi, the
frontalis, and the corrugator supercilii)
 Lower cervicofacial --- lower face.

46. Thank you