ophthalmology residency program

1.  DR.MOHAMMED MUNEER

2. Olfactory N.
 Originate from small olfacrory
receptors in the mucous mm of the
nose at the level of sup concha
 Unmylinated nerve fibers pass
through the cribriform palate of the
ethmoid bone to enter the olfactory
bulb

3.  Ofactory tract then run posteriorly in a groove beneath the frontal lobe and lateral to gyrus rectus
 Gyrus rectus forms the anterolateral wall of the suprasellar cistern
 Olf tract then divides in to
Lateral stria carries axons to the primary olfactory area of cerebral cortex whic are responsible for
olfactory sensation
Medial stria cross the medline to the opposite side
 Meningioma from arachinoid cells in the area of gyrus rectus can cause important ophthalmic sign
associated with loss of olfaction
 ( foster kennedy syndrome )

5. Optic Nerve
 It consist of more than 1 million axons that
originate in the gaglion of cell layer of the
retina and extend toward the occipital
cortex
 It is part of the brain , similar in
orginization to the white matter,
Fibers are surrounded by glial ( not
schwann ) cells sheaths
 It is divided in to 4 tpographic areas
1- intraocular ( od,prelaminar,laminar)
2- intraorbital (muscle cone)
3- intracanalicuar
4- intracranial ( end in chiasm)

7. Intraocular part
 includes the optic disc and that portion of
the optic nerve that lies within the sclera.
The optic disc lies about 3 mm nasally to the
macula lute a and slightly above the
posterior pole of the eyeball.
 It measures about (1.76mm) H , (1.92mm) V
 Physiological cup ( axon free region )
located slightly temporal to the optic disc
geometric centre
 CRV + CRA pass through the centre of the
cup
 Has 4 parts
1- superficial nerve fiber layer
2- prelaminar area
3- laminar area
4- retrolaminar area

9. superficial nerve fiber layer
 Nonmylinated nerve fiber from retina enter
the optic nerve head ,
fibers from upper retina are above
fibers from lower retina are below
temporal retina lateral
nasal retina medial
macular fibers ( 1/3 of the nerve) lateral
 In nerve head
Foveal fiber periphrally
Peripapillary fibers centrally

10. Prelaminar area
 Ganglion cell axons are suppoted by
wicker basket of astrocytic cells and are
segregated into bundles that pass
through the lamina cribrosa
 Astrocytes form 10% of the of the nerve
head volume and they replace the muller
cells in forming the ILM over the disc area

11.  Narrow pigmented cresent is present
on the temporal edge and formed by
exposed pigmented epithelium
 If the choroid and PE fail to reach the
temporal margin cresent of partial
absent of pigmentation may be
observed
 Relation btw the choroid and the
prelaminar portion acounts for
staining of the OD in the late phase of
the FFA
disc vessels do not leak
choroidal capillaries are freely
permeable for fluorescien which therefore
diffuse to the lamina

12. Lamina area
 Lamina cribrosa comprises about 10 CT plates which
are integrated with sclera and its pores transmit the
axon bundles
 Openings are wider above than below
which imply less protection from mechanical effects
of pressure in glaucoma
Contain type I , III collagen ,, elastin , laminin and
fibronectin.
 Function
1- scafold for nerve fiber axons
2- point of fixation for CRA and CRV
3- reinforcement of posterior segment of the lobe

13. Retrolaminar area
 Optic nearve diameter increase to
3mm as a result of myelination of
nerve fiber and presence of
oligodendroglia and the surrounding
meningeal sheath ( pia, arachnoid
,dura)

14. Meningeal sheath
Pia mater
 The inner most layer
 It is vascular CT coat that send septa
that divide the axon into bundles
 End just before chiasm
 Contain collagen , fibroblast , elastic
tissue , nerves and small arterioles and
venules .
 Function
1- mechanical support for the n.
Bundles
2- nutrition to the axon and the
glial cells
 ( mantle of astrocytic glial cells prevent
pia and septa from having direct
contact with nerve axons)
Arachnoid mater
 Composed of collagenous tissue ,
elastic tissue , meningothelial cells
 Subarachnoid space end
ant in the Lamina Cribrosa
post usually continous with the
subarachnoid space of the brain
 Because the CRV cross this space
so a rise in the intracranial
pressure will result in rise in the
venous pressure with in the retina
 This situation cause intraocuar
venous dilation and loss of
spontanous pulsation at the nerve
head
Dura mater
 Outer layer of the meninges
 0.3-0.5 mm thick
 Consist of dense bundles of
collagen and elastic tissue
 Fuse ant with the outer layer
of the sclera

16. Intraorbital part
 The orbital portion of the optic nerve is
about 25 mm long, which is about 6 mm
longer than the distance between the
eyeball and the optic canal. This allows
the nerve to have a slightly sinuous
course and permits freedom of
movement to the eyeball.
 The optic nerve is surrounded by a
dense sheath of dura mater, a middle
delicate sheath of arachnoid, and an
innermost vascular sheath of pia.These
sheaths, together with an extension ofthe
subarachnoid space, extend anteriorly to
the eyeball. Here the sheaths blend with
the sclera. Posteriorly, the sheaths are
continuous through the optic canal with
the meningeal coverings of the brain.

17.  About 12 mm behind the eyeball, the
inferomedial surface of the dural sheath is
pierced by the central artery and vein of the
retina. The artery crosses the subarachnoid
space obliquely before entering the optic
nerve. The vein has a more prolonged course
in the subarachnoid space lying posterior to
the artery.

18.  the optic nerve is surrounded and supported by
orbital fat in which are embedded the ciliary
vessels and nerves.
 The ciliary ganglion lies between the lateral
border of the nerve and the lateral rectus muscle
 Posteriorly, the nasociliary nerve and the
ophthalmic artery run forward and then pass
medially to cross above the optic nerve. At about
the same position, the nerve to the medial rectus
muscle from the inferior division ofthe ocu-
lomotor nerve crosses below the optic nerve
 Since the intraorbital part lie with in the muscle
cone , Superior and medial partially share a Ct
sheath with the optic nerve
 This connection may partly explain why patients
with retrobulbar neuritis report symptoms of pain
with eye movement.

19. Intracanalicular Portion
 The optic canal lies within the lesser wing of the sphenoid
bone and is about 5 mm long.
 The optic nerve passes through the optic canal
surrounded by its three meningeal sheaths. The dural
sheath fuses with the periorbita lining the canal, thus
fixing the nerve .
 ( trauma to eyebrow will transmit the force of injury to
this area which will cause shearing and interuption of
blood supply to the nerve in this area ) causing ( indirect
traumatic optic neuropathy )
 The subarachnoid space filled with cerebro- spinal fluid
around the optic nerve communicates and is continuous
with the intracranial subarachnoid space.
 Also passing through the optic canal are the ophthalmic
artery on the inferolateral border ofthe optic nerve and
the postganglionic sympathetic nerves accompanying the
artery.
 As the nerve traverses the canal it is separated on its
medial side from the sphenoidal and posterior ethmoidal
air sinuses by a thin layer of bone.

20. Intracranial Portion
 The optic nerve leaves the canal and
passes backward, upward, and medially
within the subarachnoid space to reach the
optic chiasma in the floor of the third
ventricle
 It is related
above to the olfactory tract, the gyrus
rectus, and the anterior cerebral artery;
it is related laterally to the internal
carotid artery.
below to it is the ophthalmic artery .

21. Blood Supply
Intraocular Portion
Superficial NFL
CRA
Laminar
Short post ciliary a.
Branches of arterial circle of
Zinn and Haller
Retrolaminar
Short post ciliary a.
Pial vessels
Some help from CRA and
recurrent choroidal a
Prelaminar
Short post ciliary a.
( cilioretinal a. If present )
Recurrent choroidal a

23. Orbital Portion
Proximally blood supply is from the
pial plexus vessels;
branches of the plexus pass into
the nerve along the pial septa.
The pial plexus receives its arterial
supply from neighboring branches
of the ophthalmic artery .
Most ant part is supplied by short
post ciliary a.
The intraneural part of the central
artery supply the distal part
Intracanalicular Portion
This is supplied by branches
from ophthalmic artery.
Intracranial Portion
.
This part is supplied by
branches from the superior
hypophyseal artery from the
internal carotid, and from the
ophthalmic artery

25. Optic Chiasm
 Is situated in the junction ant wall and the
floor of the 3rd ventricle
 It is 12mm wide
8mm long
4mm thick
 Anatomical relation
Ant ant ciliary a and ant communicating a
Post tuber cinereum with
infundibuum below and ventricle cavity above
Lat ICA
Sup lamina terminalis and
cavity of the 3rd ventricle
Inf diaphragma sellae and
hypophysis cerebri

26.  Aproximately 53% of the ON fiber cross and
47% are uncrossed.
 Extramacular fiber
Inferonasal fiber cross ant at ( willbrand
knee)
superonasal fiber cross at the post part of the
chiasm
The nerve fibers from the temporal half of the
retina pass backward into the optic tract of the
same side.
Macular fiber form are located centrally in the ON
and costitute 80-90% of the ON and chiasm fibers.
Nasal fiber cross in the post part in the chiasm
Temporal fiber go uncrossed through the chiasm
to the same

27. Optic tract
 The optic tracts emerge from the
posterolateral angles ofthe optic
chiasma as cylindrical bands ,, Most of
the nerve fibers in the optic tract
terminate in the lateral geniculate body
 Each optric tract contains ipsilateral
temporal and cotralateral nasal fibers
 Fibers ( crossed and uncrossed ) from
upper retina travel medially and those
from lower retina travel laterally
macular fiber adopt dorsolateral
orientation

28. lateral Geniculate Bodies
 The lateral geniculate body is a small
ovoid swelling on the undersurface of the
pulvinar of the thalamus
 lateral geniculate nucleus has a laminated
structure and consists of six curved layers
of cells oriented in a dome shaped mound,
similar to a stack of hats set one on
another.
 Layer 1,4,6 receive axons from contralatera
ON
 Layer 2,3,5 receive axons from ipsilateral
ON

29. Optic radiation
 Connect LGB with the cortex of the occipital lobe
 Those fibers arising from the lateral portions of the lateral
geniculate body, receiving impulses from the inferior retinal
quadrants (superior visual field), fan out laterally and inferiorly
around the anterior tip of the inferior (temporal) horn of the
lateral ventricle, before swinging posteriorly .
 The fibers associated with the peripheral part ofthe retina
swing farthest forward,
 and those related to the macula loop very little.
 These forward-looping fibers form the loop of Meyer
 The fibers continue posteriorly , and turn medially to enter the
occipital cortex where they end at the inf lip of calcarine fissure
 Fibers originating from the medial portions of the lateral
geniculate body, receiving impulses from the superior retinal
quadrants (inferior visual field), turn almost directly posteriorly,,
On entering the occipital cortex, the fibers terminate in the
superior lip of the calcarine fissure
 Damage to the OR in the ant tempopral lobe gives rise to
wedge shaped upper homonymous (( pie in sky )) visual field
defect

30. VISUAL CORTEX
 Is the thinnest are of the human cerebral cortex
 Has 6 celluar layers
 Occupies the sup and inf lips of the calcarine
fissure on the post and med surfaces of the
occipital lobes .
 Macular function is extremely well represented
in the visual cortex and occupies the most
posterior portion at the tip of the occipital lobe
.
 Most ant portion of the calcarine sulcus is
occupies by only contralateral nasal retinal
fibers
 Post cerebral a. ( branch of basillar a.) supplies
the visual cortex exclusively ,
Anatomical variation exist , in some indivisuals
middle cerebral a. also contributes .

31. OCULUMOTOR NERVE
 CN III contains 24000 fibers
 The oculomotor nerve involves two separate
components, each of which has a distinct
function.
somatic motor component
visceral motor component
 Somatic motor component –
Supplies four extraocular muscles in the
eye and the upper eyelid's levator palpebrae
superioris with motor (movement) fibers. - It
controls the muscles that allow for visual
tracking and fixation by the eye.
 Visceral motor component
controls parasympathetic innervation
(nerves related to involuntary actions) of the
ciliary muscles and constrictor papillae, aiding
ACCOMMODATION and pupillary light reflexes.

32.  The oculomotor nerve originates from the
anterior aspect of the midbrain.
 It moves anteriorly, passing below the
posterior cerebral artery, and above the
superior cerebellar artery.
 The nerve pierces the dura mater and enters
the lateral aspect of the cavernous sinus.
 Within the cavernous sinus, it receives
sympathetic branches from the internal carotid
plexus
 CN III ,, arises from a complex group of
cells in rostral midbrain or mesencephalon
at the level of the sup colliculus.
 CN III nucleus consist of several distinct
large motor cell sunbuclei , each of which
subserve the the EOM it innervates
 The levator palpebrae superioris muscles of
both sides are supplied by a single central
group of cells (central caudal nucleus)
 the superior rectus muscle is supplied by
the contralateral oculomotor nucleus
 the remaining muscles innervated by the
oculomotor nerve are supplied ipsilaterally

33.  The nerve leaves the cranial cavity via the
superior orbital fissure. After passing the
annulus of zinn ,, it divides into superior and
inferior branches. Once within the orbital
cavity, both branches innervate accessory
structures of the eye:
 a. Superior branch:
Motor innervation to the superior rectus and
levator palpabrae superioris.
Sympathetic fibres run with the superior branch
to innervate the superior tarsal muscle.
 b. Inferior branch:
Motor innervation to the inferior rectus,
medial rectus and inferior oblique.
Parasympathetic fibres to the ciliary ganglion,
which ultimately innervates the sphincter
pupillae and ciliary muscles.

34. Pathways of the pupil reflexes
 Light reflex
 Consist of simultaneous constriction of pipils in
response to light of one or the other eye
 The afferentr fibers coincide with tghat of the visual
pathway including a decussation of nasal fibers in the
chiasm,, at the post part of the optic tract ,, pupillary
fibers leave the visual fibers and pass to reach the
pretectal n. At the level of the sup colliculus
 Efferent fibers pass to the ( edinger westphal n ) ,,
decussating partially
 Preganglionic PSF leave each N. And run in the
oculumotor n as it leaves the brain stem ,, fibers lie
inferiorly in the inferior division of CN III as it enters the
orbit
 Fibers synapse in the ciliary ganglion and give rise to
postganglionic myelinated short ciiary nerves ,, 3-5%
of those are pupillomotor ,, the rest are designatec for
ciliary m and near reflex

35.  Near reflex
 Is synkinesis that occur when attension come from distance to near .
 Includes accomodation , pupil constriction and convergence
 Initiated in the occipital cortex ,, from which impulses descend along
corticofugal pathway to relay in pretectal and possibly tegmental
areas
 Then fibers pass to EWN , motor n of med rectus m and the n of CN
VI .
 Fibers for near reflex approach the pretectal n from the ventral aspect
,,, thus compressive dorsal lesion will spare the near reflex ( light –
near dissiciation )
 Efferent fibers for accomodation has the same pathway as those for
near reflex but their final destination is to ciliary mmuscle ..

36. TROCHLEAR NERVE
 CN IV
 Contains fewest nerve fibers (3400)
 Has the longest intracranial coarse
(75mm)
 Only motor component + completely
decussate ( contralateral SOM )
 Nucleus :
in tegmentum of the mid brain , at the
level of the inf colliculus
inferior to the n of the CN III and sup
to the MLF
 The nerve exit the brainstem just
beneath the inferior colliculus
 Pass btw the post cerebral a and sup
cerebellar a
 Pierce the dura matter to enter the
cavernous sinus
 continue in the lateral wall of the sinus
below the CN III and above the
ophthalmic division of the CN V
 Enter the orbit through the SOF outside
the annulus of zinn ( so it is not affected
by retrobulbar injection )
 Cross over the levator palpebrae
superioris and sup rectus to enter the
belly of the SOM

40. TRIGEMINAL NERVE
 Largest CN , posses both sensory and
motor component
 Sensory subserve the the greater part
of the scalp , forehead ,face ,eyelids
,eyes , lacrimal glands EOM , ears ,
dura mater and tongue
 Motor portion innervates the muscle
of mastication through branches of
mandibular division
 Nuclear complex extend from the
midbarin to the upper cervical
segments as caudal as C4
Consist of 4 nuclei ,, from above downward
1- msencephalic nucleus
2- main sensory nucleus
3- spinal nucleus and tract
4- motor nucleus located in the pons

41.  Msencephalic nucleus
proprioception
Deep sensation from masticatory , fascial, EOM
 main sensory nucleus
Lies in pons
Receive inputs from ascending branches of
sensory root
Serves light touch from skin and mucous mm
 Spinal nucleus and tract
Extend from medulla to C4
Receive pain and temp through the descending spinal tract ,
which carries cutaneous component CN VII , IX, X
That serve sensation from the ear and ext auditory meatus .
 Ophthalmic division terminate in the most ventral portion
 Maxillary division terminate in the mid portion
 Mandibuar division terminate in the dorsal portion

43.  Cutaneous territory of each of CN V division
1- perioral region terminate most rostrally
2- periphral face and scalp terminate in the caudal
portion
3- midfascial region terminate in central portion
 Damage to the trigeminal nerve at the level of
the brain stem
bilateral sensory loss of the concentric area of
the face ,, with sensory area surrounding the mouth
in the center
 Lesion outside the brain stem
Sensory loss that follows the periphral distribution
of the trigeminal sensory divisions ( opth , maxillary
,, mandibular )..

45.  Motor nucleus
 Located medial to the main sensory n in the pons
 Receive fibers from boh cerebral hemispheres
( reticular formaion ,, red nucleus ,, tectum ,, MLF ,, and
mesencephalic nucleus )
 Motor nucleus send off axons that form the motor root
which supplies the muscle of mastication ( pterygoid ,,
masseter ,, temporalis ) ,, tensor tympani , tensor veli
palatini ,, mylohoid muscle,, ant belly of digastric muscle ..

46.  Intracranial coarse
 Emerge from the lateral portion of the pons
 Form the trigemenal ganglion ( gasserian ganglion ) which
occupies a recess in the dura mater ( meckel cave ) it is
the apex of the petrous part of the temporal bone in the
middle cranial fossa ,,
medially related to ICA
posteriorly related to cavernous sinus
 Then the nerve is divided into 3 branches
Ophthalmic V1
Maxillary V2
Mandibular V3

47. OPTHALMIC DIVISION
 Enters the cavernous sinus
lateral to ICA
inferior to CN III ,, IV
 With in the sinus gives off ( tetorial – doral branch ) which
supply sensation to :
dura mater of the ant fosa ,, cavernous sinus ,, sphnoid
wing ,, meckel cave ,, tentorium cerebelli ,falx cerebri
 Then it passes through the SOF where it divides into 3
branches
 Frontal
 Lacrimal
 nasociliary

49. Frontal nerve
It divides into supraorbital and
supratrochlear branches
Provide sensation to the medial part
of the eyelid ,, conjunctiva,,
Forehead ,, scalp ,, frontal sinus ,,
side of the nose
Lacrimal nerve
It innervates the lacrimal gland and
adjacent conj and skin
Exit the orbit through the lacrimal
foramen to innervate the lateral part
of the forehead

50. 1) ramus communicans to the ciliary ganglion
arises from the nasociliary nerve as soon as it enters the orbital cavity
,, after a short course enters the ciliary ganglion. The ramus contains
sensory nerve fibers from the eyeball.
The sensory fibers reach the ganglion from the eyeball by the
short ciliary nerves. They pass without interruption through the
ganglion to reach the ramus and so enter the nasociliary nerve.
2) long ciliary nerves
usually two in number, arise from the nasociliary nerve as it crosses
the optic nerve,, The long ciliary nerves are made up of
1) sympathetic postganglionic fibers to the dilator pupillae muscle
and
2) sensory fibers from the cornea,iris , ciliary body.
3) infra trochlear nerve
arises from the nasociliary nerve close to the anterior ethmoidal
foramen .The infratrochlear nerve supplies the lacrimal sac, the
conjunctiva, the skin of the medial parts of the lower eyelids, and the
upper part of the lateral aspect of the nose.
4) posterior ethmoidal nerve
It arises close to the posterior ethmoidal foramen .
It supplies the ethmoidal and sphenoidal air sinuses.
 Nasociliary nerve
 It enters the orbit through the superior orbital
fissure ,, It lies within the tendinous ring.
 The nasociliary nerve ends by passing through
the anterior ethmoidal foramen, where it
becomes what known as the anterior ethmoidal
nerve..
 The anterior ethmoidal nerve supplies the
mucous membrane of the anterior ethmoidal
air cells ,, gives off two internal nasal nerves,
which are distributed to the mucous membrane
of the upper part of the nose,,
 The terminal part of the anterior ethmoidal
nerve supplies the skin on tip of the nose.
 The branches of the nasociliary nerve are as
follows:
 1) ramus communicans to the ciliary ganglion
 2) long ciliary nerves,
 3) infra trochlear nerve, and
 4) posterior ethmoidal nerve. .

51. Maxillary division V2
 Exit the skull through foramen
rotundum which lie below the SOF
 Then coarse through ptergopalatine
fossa into IOF and pass through inf
orbital canal as infraorbital nerve ..
 Then didvides into
1- inf palpebral branch which supply the
lower eyelid
2- nasal branch for the side of the nose
3- sup labial brach for upper lip
Mandibular division V3
 Contain sensory and motor fibers
 Exit the skull through foramen ovale
 Motor input for masticatory muscles
 Sensation supply to mucosa and skin
of the mandible , lower lip , tongue ,
external ear , tympanum

52. ABDUCENS NERVE
 CN 6
 Nucleus is situated in the floor of the 4th
ventricle in the caudal pons
 MLF lie medial to CN VI
 Fascicular portion leaves the brain stem
in the pontomedullary junction
 Coarse vertically along the ventral face
of the pons ,, continues through the
subarachinoid space along the surface
of the clivus
 Perforate the dura mater approximately
2cm below the post clinoid process
 Then pass beneath petroclinoid
(.GRUBER.) lig through the dorello canal
where it enters the cavernous sinus
 In the cavernous sinus runs below
and lat to the carotid artery
 Pass through the SOF within the
annulus of Zinn
 Innervates the lateral rectus muscle