This PPT is very beneficial for undergraduate medical students

1. Dr. Atul Kumar Anand
Senior Resident
AIIMS Patna

3. Quadrangular pyramid or pear shaped
space b/w anterior cranial fossa above &
maxillary sinus below.
Formed by portion of Seven bones (viz: 1.
frontal, 2. maxilla, 3. zygomatic, 4.
sphenoid, 5. palatine, 6. ethmoid, 7.
lacrimal
Nasal bone not involved in orbit formation

5.  Has four walls, base & apex
Roof: by 2 bones, triangular shape, orbital
plate of frontal & lesser wing of
sphenoid.(lacrimal gland in superotemporal part, so its
tumor push globe inferonasally)
Lateral wall: by 2 bones, greater wing of
sphenoid & zygomatic Thickest wall,
Floor: by 3 bones, zygomatic maxillary &
palatine, quite thin wall, frequently invoved in
blow out fracture.

6.  Medial wall: by 4 bones frontal process of maxilla,
lacrimal ethmoid & sphenoid Thinnest wall {so
infection of ethmoidal sinus spread easily to orbit
causes orbital cellulitis, specially in child as orbital
plate of ethmoid [lamina papyracea ] is absent in child}
has lacrimal fossa formed by lacrimal bone & frontal
process of maxilla
Base of orbit: anterior open end of orbit,
bounded by thick orbital margin

7. Apex of orbit:
posterior end of
orbit , all four
orbital wall
converge here,
has two orifices
optic canal &
superior orbital
fissure

8. Volume of orbit: 30cc, about 1/5th occupied
by eyeball( 6.5cc)
Other content of orbit include part of optic
nerve, EOM, lacrimal gland, lacrimal sac
ophthalmic artery, 3rd, 4th,6th, ophthalmic &
maxillary division of 5th cranial nerves
sympathetic nerve, orbital fat & fascia
Depth of orbit 40mm
Inter orbital distance 25mm

9. Lies b/w roof & lateral wall of orbit in gap
b/w lesser & greater wing of sphenoid.
Comma shaped, 22mm long,longest
connection b/w orbit & middle cranial fossa
Two parts: narrow lateral portion & wider
medial portion, at the junction of two is
spina recti lateralis –LR originates here

11.  Structure passing above common tendinous
ring: lacrimal nerve. Frontal nerve, trochlear
nerve, superior ophthalmic vein & recurrent
laryngeal nervve
 Structure passing within tendinous ring:
superior division of 3rd nerve, inferior division
of 3rd nerve, nasociliary nerve, 6th cranial
nerve, sympathetic root of ciliary ganglion,
inferior ophthalmic vein.

12. Formed by lesser wing & body of sphenoid
Vertically oval
Length 6mm, diameter 4mm
Transmits :1. Optic nerve & its meningeal
covering(dura, arachnoid, & piamater)
2. Ophthalmic artery

13.  From surgical point of view 4 spaces which
are relatively self contained, within each of
which inflammatory process are contained for
a considerable time, if necessary, be opened
separately.
Subperiosteal space: potential space b/w
bone of orbital wall & periorbita(periosteum)
Peripheral/Extraconal space: b/w
periorbita & EOM.(peribulbar anaesthesia injection is
given in this space) tumor present here cause eccentric
proptosis.

14. Central/Intra-
conal/Retrobul
bar space: also
KA Muscle cone,
a cone shaped
area enclosed
by EOM. Tumor
here produce axial
proptosis, (retro-
bulbar injection
site)

15. Tenon’s Space: potential space around
eyeball b/w sclera & tenon’s capsule.

17.  Position: UL covers
1/6th of cornea, LL just
touches limbus.
 Canthus: The two lids
meet each other at
medial & lateral angles.
 Palpebral aperture
elliptical space b/w
lids, vertical 10-
11mm in centre,
horizontal 28-30mm

18.  2mm broad, divided by
punctum in two parts,
Medial Lacrimal portion is
rounded & devoid of
lashes or gland, lateral
ciliary portion consists of
a rounded anterior border,
a sharp posterior
border(placed against
globe) & an intermarginal
stripe(b/w the two
borders)

19. The Grey line(junction of skin &
conjunctiva) divides intermarginal stripe
into anterior part bearing eyelashes –
about100-150 in UL & half in LL and
posterior part on which openings of
meibomian glands are in vertically parallel
row, has surgical importance (splitting of lid
done at this level)

21.  Following layers from Anterior to Posterior
Skin: thinnest in the body, fine & elastic
Subcutaneous areolar tissue: very
loose, no fat, so easily distended by edema
Layers of striated muscle: contains
orbicularis oculi forms an oval sheet across
eyelid, it closes eyelids. In UL also contains
Levator Palpebrae Superioris(LPS), it arises
from apex of orbit & inserted by three parts

22.  On skin of lid, anterior surface of tarsal plate &
conjunctiva of superior fornix. It raises UL.
Submascular areolar tissue: loose
connective tissue nerves & vessels lie in this
layer
Fibrous layer: framework of lid, two parts,
central tarsal plate & peripheral orbital septum
Tarsal plate: one for each lid, give shape &
firmness to lid, upper & lower tarsal plate join

23.  With each other at medial & lateral canthi &
attached to orbital margin by medial & lateral
palpebral ligaments.
Orbital septum: thin connective tissue attached
centrally to tarsal plate & peripherally to
periosteum of orbital margin.
Layers of non- striated muscle: contains
Muller muscle, in UL arises from LPS fibres & in
LL from prolongation of inferior

24.  rectus, & inserted on peripheral margin of tarsal
plate.
Conjunctiva: lines the lid & this part of
conjunctiva KA palpebral conjunctiva.

26. Meibomian gland: modified sebaceous
gland, present in tarsal plate(KA Tarsal gland),
vertically parallel, in UL 30-40 & LL 20-30, duct
opens at lid margin, secretion constitute lipid
layer of tear film.
Gland of Zeis: modified sebaceous gland,
duct opens into follicles of eyelashes.
Gland of Moll: modified sweat gland(the only
sweat gland of lid), at hair follicle, open into hair
follicle or into duct of Zeis gland.

27. Both lid by marginal arterial arcade, UL
also by superior arterial arcade.
Veins: two plexus, post tarsal into ophthalmic
vein, pre tarsal into subcutaneous vein.
Lymphatics: lateral half of lids drain into
preauricular lymph nodes & medial half of lids
into submandibular lymph nodes.

28. Motor nerves: orbicularis by zygomatic
branch of facial,(in facial palsy lagophthalmos–
exposure keratitis) LPS by oculomotor & Muller
muscle by sympathetic fibre( in 3rd nerve palsy
ptosis due to LPS, complete ptosis, as in UL
Muller arise from LPS){ in Horner syndrome due
to sympathetic lesion ptosis due to Muller
muscle, so partial ptosis}

30. A translucent
mucous
membrane which
lines posterior
surface of the
eyelids and
anterior aspects of
the sclera.
‘Conjoin’ means to
join (it joins the
eyeball to the
eyelid)

31. 1. Palpebral Conj : it lines the eyelid,
firmely adherent
(sulcus subtarsalis: shallow groove common
location for extraocular FB)
2. Bulbar Conj : loosely adherent to
anterior sclera, moved easily, 3mm ridge
around cornea KA limbal conjunctiva,
where its epithelium becomes continuous
with that of corneal epithelium.

32. 3. Conjunctival Fornix : joins the bulbar
conjunctiva with palpebral conjunctiva.
(divided into superior, inferior, medial &
lateral fornices.)

33. Three layers :
Epithelium : stratified sq. non keratinized
Adenoid layer : also KA lymphoid layer
Fibrous layer

34. Two types
Mucin secretory glands : are goblet
cells (crypts of Henle in palpebral conj. &
glands of Manz in limbal conj.) secret
mucin : a component of tear
Accessory lacrimal gland : glands of
Krause & glands of Wolfring.

35. Pinkish crescentric
fold of conj. in
medial canthus,
lateral free border
concave, vestigeal
str. in human,
represents
nictitating memb. of
lower animal

36. Small ovoid pinkish
mass in inner
canthus, just medial
to plica semilunaris,
piece of modified
skin, so contains
sweat & sebaceous
gland & hair follicles

37. Arteries : peripheral arterial arcade of the
eyelid
marginal arcade of the eyelid
anterior ciliary arteries
Veins : drain into the venous plexus of the
eyelid

38. Arranged in two layers : superficial &
deep
From lateral side drain into
Preauricular lymph node
From medial side drain into
submandibular lymph node

39. Circumcorneal zone by branch from
long ciliary nerve
Rest of conjunctiva by branches from
lacrimal, infratrochlear, supratrochlear,
supraorbital & frontal nerves

41. Cornea :
Transparent
Sclera :
opaque
{both avascular
(sclera proper)}

42. Corneoscleral
junction KA
Limbus.(where
bulbar conjunctiva
Tenon’s capsule &
episcleral tissue
fused & strongly
adherent to it.
Limbus is marked by
shallow sulcus KA
Sulcus sclerae

43. Tough white
coloured opaque
structure
Lamina cribrosa :
sieve like sclera
from which fibres
of optic nerve
pass

44. Whole outer surface covered by Tenon’s
capsule, in anterior part it is also covered
by bulbar conjunctiva.
Inner surface lies in contact with choroid
with a potential suprachoroidal space in
between. It is pierced by anterior Ciliary
arteries & episcleral vein anteriorly and
vortex vein, posterior ciliary nerve &
vessels and optic nerve posteriorly.

45. Thee layers:
Episcleral tissue: thin vascularised layer.
Sclera proper: an avascular structure.
Lamina fusca: innermost layer.
Nerve supply: by branches from long
ciliary nervs which pierce it 2-4mm from
limbus & form a plexus.

46. Refractive power about +45D (about 3/4th
of total refractive power{+60D} of eye)
Refractive index 1.376 (1.38)
Thickness: central 0.5-0.6mm , peripheral
1.2mm
Diameter horizontal 11.7, vertical 10.6
Avascular & devoid of lymphatics.

48.  Five layers:
Epithelium: stratified sq. non keratinized, 5-6
layer, excellent property to regenerate(from
epithelial stem cell present as Palisade of Vogt at limbus)
Bowman’s layer: condensed superficial
stroma, does not regenerate, once damaged
leaves opacity
Stroma: thickest layer(90% thickness)
consists of collagen fibrils(lamellae)

49. Descemet’s membrane: strong layer, very
resistant to chemical agent, trauma, &
infection, can regenerae to some extent.
Endothelium: single layer, hexagonal cells,
density at birth 2500- 3000
cells/mm2,(specular microscopy) with age
No. decreases, 1500-2000 cells/mm2 in adult,
does not regenerate but adjacent cell slide to
fill in a damaged area, have Na+K+ATPase
pump, imp. role in transparency of cornea.

50. By long ciliary nerve which is branch
of ophthalmic division of the 5th cranial
nerve.
Nerve fibres are unmyelinated.(forms
three plexus).
Due to dense nerve supply cornea is
extremely sensitive.

51. Tear film for maintaining corneal epithelial
cell healthy.
Relative Dehydrated State: maintained
by barrier effect of hydrophobic epithelium,
endothelium, endothelial pump & osmotic
gradient of tear & aqueous(as hypertonic). epithelium
& endothelium maintain steady fluid content of
cornea(trauma to either of these layers produce corneal
edema, in acute glaucoma raised IOP open endothelial
pump pushing aqueous into cornea causing edema----
compromising transparency.

52. Avascularity
Unmyelinated nerve fibres
Uniform refractive index of all layers
Uniform spacing of collagen fibrils in
stroma(lattice arrangement of corneal
lamella) collagen fibrils are separated by a distance
which is less than wavelength of light(400-700nm) so
any irregularly refracted rays of light are eliminated by
destructive interference. If increase in separation or
loss of this arrangement cornea becomes opaque.

54.  From anterior to posterior
three parts:
Iris
Ciliary body
Choroid

55.  Anterior most part of
uveal tissue
 Diameter – 21mm
 Central aperture 3-4mm in
diameter KA pupil,
regulate amount of light
reaching retina
 At periphery attached to
anterior surface of ciliary
body, where iris is
thinnest
 Divides space b/w cornea
& lens into anterior &
posterior chamber

56.  Divided by collarette
(thickest part, 2mm from
pupil) into inner pupillary
zone & outer ciliary zone.
 Crypts are depressions
where superficial layer of
iris missing, present in
ciliary zone, arranged in
two rows:- peripheral
present near iris root &
central present near
collarette, allows easy
transfer of fluid b/w iris &
anterior chamber

57.  From anterior to posterior:
Anterior limiting layer: (previously KA endothelial
layer) consists of melanocytes & fibroblast, so color of
iris depends on this layer, deficient in crypts
Iris Stroma: consists of loose connective tissue, in it
embedded:- sphincter pupillae, dilator pupillae muscle
vessels, nerves, pigment cells
 Sphincter pupillae: circular 1mm broad smooth
muscle, form a ring all around pupillary margin, derived
from neuroectoderm, supplied by 3rd cranial
nerve(parasympathetic), constrict the pupil

59.  Dilator pupillae: thin
layer of plain muscle fibre,
extend from pupil to iris,
supplied by cervical
sympathetic nerve, dilates
the pupil.
Anterior epithelial
layer: anterior
continuation of pigment
epithelium of retina &
ciliary body

60. Posterior pigmented epithelial layer: anterior
continuation of non pigmented epithelium of ciliary body.
Nerve supply:
 Iris richly supplied by sensory nerve fibres from
trigeminal nerve
 Sphincter pupillae by 3rd CN(parasympathetic)
 Dilator pupillae by cervical sympathetic chain

62.  Forward continuation of
choroid at ora serrata,
begins 1mm behind limbus,
in cut section triangular in
shape, two parts: -Anterior
part( 2mm) have finger like
ciliary process(KA Pars
Plicata ) each process
2mm long & 70-80 in NO.
These are site of aqueous
production. Posterior
smooth part (4mm) KA
Pars Plana

63. CUT SECTION
CILIARY
PROCESS

64.  Microscopic structure :- from without inwards(5 layers)
 Supraciliary lamina
 Stroma
 Layers of pigmented epithelium
 Layers of non-pigmented epithelium
 Internal limiting membrane
 Stroma of ciliary body contain ciliary muscle(smooth
muscle),which has 3 parts, outermost– longitudinal, middle–
oblique(radial), & inner-- circular, action –
Accommodation(helps in near vision), this is mainly done by
circular & radial part of muscle
 Resting tone of ciliary muscle is +1D
 Richly supplied with sensory nerve fibres fom trigeminal nerve
ciliary muscle supplied with motor fibre by 3rd CN

66.  Posterior most part of uveal
tissue, extremely vascular,
pigmented
 Extends from optic disc to
ora serrata
 Inner smooth brown surface
lies in contact with RPE of
retina
 Outer rough surface lies in
contact with sclera with a
potential space in between
the two KA supra- choroidal
space

67.  From without inwards
following layers
 Suprachoroidal lamina or
lamina fusca: supra-
choroida space b/w this &
sclera, contains long &
short posterior ciliary
arteries & nerves
 Stroma: loose connective
tissue, contains layersof
large vessels, layer of
medium vessels, & layer of
choriocapillaris

68. Basal lamina/Bruch’s membrane: firmly
adherent to RPE
Choroid is supplied with sensory nerve
fibres from trigeminal nerve (so sensory
supply of whole uvea by trigeminal nerve)

69.  Uveal tract is supplied by:- ciliary arteries, which are divided
into three groups– short posterior, long posterior & anterior
 Short posterior ciliary arteries – supply choroid
 Long posterior ciliary & anterior ciliary arteries -- supply iris &
ciliary body
Short posterior ciliary arteries: arise as two trunks
from ophthalmic artery; each trunk divides into 10-20
branches which pierce sclera in a ring around optic nerve &
supply choroid in a segmental manner.
Long posterior ciliary arteries: two in NO.(nasal &
temporal), derived from ophthalmic artery, pierce sclera
obliquely on medial(nasal) & lateral(temporal) side of optic
nerve & run forward in supra choroidal space to

70.  reach ciliary muscle, without giving any branch. At anterior
end of ciliary muscle these anastomose with each other &
with anterior ciliary arteries & gives branches which supply
ciliary body.
Anterior ciliary arteries: derived from muscular
branches of ophthalmic artery. 7 in NO. 2 each from arteries
of SR, IR & MR and one from that of LR muscle. These
arteries pass anteriorly in episclera, give branches to sclera,
limbus & conjunctiva and ultimately pierce sclera near
limbus to enter ciliary muscle where they anastomose with
two long posterior ciliary arteries to form circulus arteriosus
major(major arterial circle),near root of iris

71.  Several branches arise from circulus arteriosus major &
supply ciliary processes(one branch for each process).
Similarly, many branches from this major arterial circle run
radially through iris towards pupillary margin, where they
anastomose with each other to form circulus arteriosus
minor(minor arterial circle)
 Major arterial circle: site-- on ciliary body & root of iris,
made of long posteror ciliary arteries & anterior ciliary
arteries.
 Minor arterial circle: present at collarette of iris.
Venous drainage: series of small veins which
drain blood from iris, ciliary body & choroid join to form
vortex vein

72. Vortex vein are 4 in NO.-
superotemporal, inferotemporal,
superonasal & inferonasal. They pierce
sclera behind equator & drain into superior &
inferior ophthalmic veins which ultimately
drain into cavernous sinus.

73.  Coloboma means absence of tissue
 Congenital coloboma of iris, ciliary body & choroid may be
seen in association or independently.
 May be typical or atypical
 Typical coloboma: seen in inferonasal quadrant, occurs
due to defective closure of embryonic fissure.
 Atypical coloboma: found in other position
 Complete coloboma: extends from pupil to optic nerve,
with sector shaped gap involving retina, choroid, ciliary
body, iris & indentation of lens where zonular fibres
missing

76.  Extends from optic disc to
ora serrata
 Purplish red background
colour due to RPE &
vascular choroid
 Neurosensory retina is
transparent
 Divided into two region :
posterior pole and
peripheral retina by
imaginary line called
retinal equator.

77.  Retinal equator: an imaginary line, considered to lie in
line with exit of 4 vortex vein.
Ora serrata: serrated peripheral margin where retina
ends, here retina firmly attached both to vitreous &
choroid.
 Retina posterior to equator is posterior pole (& anterior to
equator upto ora serrata is peripheral retina which is best
examined by indirect ophthalmoscope)
 Posterior pole have two distinct area: Optic disc &
Macula lutea.

78. Optic disc(ONH):
pink coloured, 1.5mm
diameter, only layer
peresnt- nerve fiber layer
which pass through
lamina cribrosa to run into
optic nerve. A depression
seen in disc KA
physiological cup, normal
C:D ratio=0.3, (increase in
glaucoma)

79.  On Optic Disc--No photoreceptors,--if light falls—no
visual Impression excited, so KA BLIND SPOT.
 Disc Diameter(1.5mm)– unit of measurement in retina.
 Central retinal artery & vein emerge through centre of
Cup
Macula Lutea: also KA yellow spot, small,
circular area, comparatively deeper red due to pigment
xanthophyll, 5.5mm in diameter, situated about
3mm(2DD) temporal to optic disc & a little below the
horizontal meridian,
Fovea centralis: depression in centre of macula,
1.5mm(1DD) in diameter, 6-8 layers of ganglion
cells(outside macula only one layer)

81. Foveola: central depression in fovea, 0.35mm in
diameter, only cones, no rod present, THINNEST part of
retina, one cone connected to one ganglion cell( in rest of
retina one ganglion cell connected to 100 cones),so
vision most acute at foveola
 Site of maximum vision- foveola> Fovea> Macula.
 Foveal Avascular Zone(FAZ): no retinal blood
vessels at fovea itself & for a short distance around the
centre known as FAZ.
 Thickness of retina: not uniform, 100 micron at ora
serrata, 350 micron at macula(THICKEST), 90micron at
foveola(THINNEST)

82.  10 layers of retina from without inwards:
 Retinal Pigment Epithelium(RPE)
 Layers of Rods & Cones(Photoreceptors)
 External Limiting Membrane(ELM)
 Outer Nuclear Layer(ONL)
 Outer Plexiform [Molecular] Layer(OPL)
 Inner Nuclear Layer(INL)
 Inner Plexiform [Molecular] Layer(IPL)
 Ganglion Cell Layer(GCL)
 Retinal Nerve Fibre Layer(RNFL)
 Internal Limiting Membrane(LM)
 Inner 9 layers of retina collectively KA Neuro-sensory
Retin(so 2 layers develomentally:- RPE & Neuro-sensory retina)

84.  RPE: outermost layer, extends from ONH to ora serrata,
single layers of cells firmly adherent to Bruch’s
membrane of choroid but loosely to rods & cones, many
function, also macrophagic function, forms part of outer
Blood Brain Barrier
 Layers of rods & cones: name derived from shape of
cell--- rods– long & cylindrical, cones – conical, Rods
contain photosensitive pigment Rhodopsin, helps in
peripheral vision & dim light vision(Scotopic vision),
about 120 milions rods & 6.5 millions cones in retna,
cones help in central vision(photopic vision) & color
vision

85.  ONL: consists of nuclei of rods & cones
 OPL: involved layer in CME
 RNFL: consists of axons of ganglion cells which
pass through lamina cribrosa to form optic nerve,
layer damage in glaucoma.
 ILM: innermost layer that separates retina from
vitreous.

86.  Outer 4 layers of retina(RPE, layers of rods &cones, ELM &
ONL) get nutrition from choroidal vessels
 Inner 6 layer supplied by central retinal artery, a branch of
ophthalmic artery.
 Central retinal artery: emerges from centre of cup of optic
disc &divides into 4 branches namely: supero-nasal,
supero-temporal, infero-nasal, infero-temporal. These are
end arteries(do not anastomose with each other)
 Retinal veins follow pattern of retinal arteries Central
retinal vein drains into cavernous sinus directly or through
superior ophthalmic vein.

88.  Transparent,Biconvex
crystalline structure
placed b/w iris &
vitreous KA patellar
fossa
 Diameter 8.8-9.2mm
 Antero-posterior
thickness changes
with accommodation
 Has two surfaces:
anterior surface less

89.  Convex( radius of curvature 10mm) than
posterior(radius of curvature 6mm), these two
surfaces meet at equator. Anterior surfaces
shortens with accommodation.
 Lens grows throughout life(unique organ), weight
at birth 65mg & by 80 yrs 258mg
 35% refractive power eye(power +18 to 20D)
refractive index 1.42(nucleus has high RI than
cortex) accommodative power of lens varies with
age(at birth 14-16D,7-8D at 25yrs,1-2D at 50yrs
of age)

90. Composed of 64% water, 35% protein & 1%
lipid carbohydrate & trace element(protein
concentration in lens is highest amongst
body tissue), main type of protein are
alpha[31%] beta[55%] & gamma[2%]
crystallins{so called crystalline lens} and
insoluble albuminoids[12%]

92. Lens capsule: thin, transparent, elastic, anterior
capsule is 3 times thicker than posterior. Thickest at pre-
equator region & thinnest at posterior pole
Anterior epithelium: single layer cuboidal cells
linnig anterior capsule, cells are of two types, in central zone
not actively dividing, in pre-equatorial germinative zone that
give rise to lens fibre. Lens fibre elongates undergo
differentiation, loss of cell organelles & nucleus. As new lens
fibre form, older one pushed towards depth of lens, so
youngest fibres are most superficially located (no
correspondig posterior epithelium)

93. Nucleus: central part consists of densely compacted,
oldest fibre, depending upon period of development
different zone of lens nucleus:
 Embryonic nucleus: innermost part of nucleus, upto 6-
12 weeks of embryonic life. Primary lens fibre.
 Fetal nucleus: around embryonic nucleus, upto 3-8
months of fetal life, fibres meet around sutures, anterior
Y shaped, posterior inverted Y shaped, secondary lens
fibres.
 Infantile nucleus: last month of IU life till puberty.
 Adult nucleus: after puberty to rest of life.
Cortex: peripheral part b/w capsule & nucleus.

94. Suspensory ligament: that suspend
lens from ciliary body, attached to ciliary
process of pars plicata & pars plana’
Holds lens in position & have role in
Accommodation--- ciliary muscle
contracts---- zonules relax--- lens more
convex(increase in lens power)--- near
object better viewed (accommodation)

95.  Maintained by regular arrangement of lens fibres which
are devoid organelles & nucleus.
 Avascularity
 Devoid of nerve supply
 Pump mechanism of lens fibre membrane that regulate
electrolyte & water balance, maintaining Relative
Dehydration.
Loss of transparency--- opacity--- cataract

97.  Comprises of main
lacrimal gland,
accessory lacrimal
gland & lacrimal
drainage system(viz:
puncta, canaliculi
lacimal sac & naso
lacrimal duct NLD)

98. Main lacrimal gland: 95% of aqueous component of
tear, two parts
Orbital parts: large superior part, lies in anteolateral
part of roof of orbit in orbital plate of frontal bone(fossa for
lacrimal gland)
Palpebral part: small inferior part, lies in fornix &
palpebral conjunctiva
 Lacimal gland is tubulorecemose gland
 Duct of lacrimal gland: 10-12 ducts open in lateral part of
superior fornix, 1-2 duct in lateral part of inferior fornix

99.  Main lacrimal gland is supplied by lacrimal artery, a branch
of ophthalmic artery
 Lymphatics: to conjunctival lymphatics—preauricular lymph
nodes
 Nerve supply: sensory supply from lacrimal nerve, a branch
of ophthalmic division of 5th nerve
Accessory lacrimal gland: 5% of aqueous
component of tear, gland of Krause in palpebral conjunctiva–
about 42 in upper fornix, 6-8 in lower fornix, gland of
Wolfring—superior &inferior tarsus

100.  Puncta: one small
opening each on upper &
lower lid on papila
lacrimalis, prominent in old
age, normally puncta dip
into lacus
lacrimalis(collection of tear
in medial canthus)
 Canaliculi: join puncta to
lacrimal sac, two parts:
vertical(2mm) &
horizontal(8mm), horizontal
part converge towards
inner canthus to open in
sac

101.  Two canaliculi may open
separately or may join to form
common canaliculus which
opens in lacrimal sac, common
canaliculus– guarded by valve
of Rosenmuller– prevents
reflux of tear from sac to
canaliculi
 Lacrimal sac:10-15mm long,
lies in lcrimal fosaa(formed by
lacrimal bone & frontal process
of maxilla) b/w anterior &
posterior lacrimal crest in
medial wall of orbit.

102.  Sac has 3 parts: Fundus(portion above opening of
canaliculi), Body(middle part),& Neck(lower small part
continuous with NLD)
 In front of sac Medial Palpebral ligament(MPL), Angular vein
crosses MPL 8mm from medial canthus
Nasolacrimal Duct(NLD): 24mm long, extends from
neck of sac to Inferior meatus of nose Direction:-
backwards, laterally & downwards, externally its location
represented by a line joining inner canthus to ala of nose,
opening(lies 3cm from external nare) guarded by valve
of Hasner which prevents reflux from nose

105. Plays an important
role in aqueous
drainage
Clinically angle
structures seen by
Gonioscope/Goniol
ens

106. From anterior to posterior
Schwalbe’s Line(SL): corresponds to
peripheral termination of Descemet’s membrane
of cornea.
Trabecular Meshwork(TM): - 2 parts
 Parts adjacent to schwalbe’s line – whitish, non-
functional
 Functional part – pigmented, lies adjacent to
schlemm’s canal

107. Scleral Spur(SS): part that is attached to
longitudinal part ciliary muscle
Ciliary Body Band(CBB): dull brown
Root of Iris(ROI):

108.  it includes:-
Trabecular meshwork: sieve like structre,
consists of three portion:--Uveal meshwork,
Corneoscleral meshwork & juxtacanalicular
meshwork
Schlemm’s canal:
Collector channels:
Aqueous vein:
Episcleral vein:

110. Grade Angle width
in degree
Structures
visible on
gonioscope
Configration Chances of
closure
0 0 None of angle
structure
Closed angle Closed
I 10 SL only Very narrow High
II 20 SL, TM Narrow Possible
III 20-35 SL, TM, SS Open angle Nil
IV 35-45 SL, TM, SS,
CBB
Wide open NIl

114.  6 in NO.
 4 recti & 2 obliques
 SR
 IR
 MR
 LR
 SO
 IO

115.  All EOM (Except IO)
originate from a common
tendinous ring(annulus of
zinn) attached at orbital
apex .
 All recti inserted into sclera
anterior to equator by flat
tendons at different
distances from limbus as
under
 MR – 5.5mm (closet to limbus)
 IR – 6.5mm
 LR – 7mm
 SR – 7.7mm (farthest from
limbus)

116. SO: arises from orbital apex run forward & turns
around a pulley(KA trochlea present at anterior
part of superomedial angle of orbit) & inserted in
upper & outer part of sclera behind equator.
IO: arises anteriorly from lower & inner orbital
wall near lacrimal fossa, passes laterally &
backward to be inserted into lower & outer part
of sclera behind equator.
Nerve Supply: SO4, LR6 & RO3

117. Muscle Primary action Secondary action Tertiary action
MR Adduction
LR Abduction
SR Elevation Intorsion Adduction
IR Depression Extorsion Adduction
SO Intorsion Depression Abduction
IO Extorsion Elevation Abduction