Conjunctival anatomy

CONJUNCTIVA
Anatomy & Blood Supply
Dr Md Afzal Mahfuzullah
MCPS,FCPS,Felow Vitreo-Retina
Assistant Professor(Vitreo-Retina)
Bangabandhu Sheikh Mujib Medical University

Introduction
Conjoin = to join
So the name conjuctiva has
been given to this mucous
membrane owing to the fact
that it joins the eyeball to
the lids
It is a translucent mucous
membrane which lines the
posterior surface of the
eyelids and anterior aspect
of the eyeball

The normal conjuctiva is
o Pink
o Smooth
o Thin
o Transparent
There are normally large
deep blood vesells that run
vertically

Functions of conjunctiva
The conjunctiva helps lubricate the eye by
producing mucus and tears, although a smaller
volume of tears than the lacrimal gland
It also contributes to immune surveillance and helps
to prevent the entrance of microbes into the eye

Parts of the conjunctiva
Conjunctiva
Palpebral
Marginal
Tarsal
Orbital
Bulbar
Scleral Limbal
Fornix
Superior
Inferior
Lateral
Medial

Palpebral conjunctiva:
o It is richly vascular, extremely thin and strongly
bounded to the tarsal plate

oIt lines the lids and is subdivided into
marginal
tarsal
orbital

Marginal-
o Extends from the lid margin to about 2mm back of
the lid upto the sulcus subtarsalis
o Actually a transitional zone between skin and the
conjunctiva proper
o Lacrimal puncta open in the marginal zone

Tarsal-
o Thin, transparent and highly vascular
o Firmly adherent to the whole tarsal plate in the
upper lid and only to half width of the tarsus in
the lower lid
o The tarsal glands are seen through it as yellow
streaks

oOrbital-
o It lies loose between the tarsal plate and the
fornix
o Orbital margin of the upper eyelid is loose and lies
over the muller’s muscle

Bulbar conjunctiva-
o It is transparent and
lies loose over the
underlying structures
and thus can be
moved easily
o It is separated from
the anterior sclera by
episcleral tissue and
o tenon’s capsule

o The average thickness is 33 microns
o It is also known as ocular conjunctiva
o It is further of two types
Limbal
Scleral

 Limbal-
o A 3mm ridge of bulbar conjunctiva around the
cornea is called limbal conjunctiva
o Strongly adherent to sclero-corneal junction
 Scleral-
o Covers the eyeball above the anterior sclera and
hence known as scleral conjunctiva
o Thin, transparent & loosely attached to underlying
sclera
o Separated from the sclera by episcleral vessels and
Tenon’s capsule

oConjunctival fornix:
o It is thin, transparent , continuous circular cul-de-
sac
o It is broken only on the medial side by caruncle
and the plica semilunaris
o It joins the bulbar conjunctiva with the palpebral
conjunctiva

Lateral
Medial
inferior
It is further of four types
Superior

oSuperior
o Located at the level of superior orbital margin
o Extends from slightly upper border of the tarsal
plate to a distance about 10mm from the upper
limbus
o Here we can find the glands of Krause and
o Mullers’s muscle in the subconjunctival tissue

oInferior fornix
o Extends from slightly below the lower border of the
lower tarsal plate to a distance about 8mm from the
lower limbus
o Located near the inferior orbital margin
o Helps in maintaining the recess of the inferior fornix
during movements of the lower lid

oLateral
o Small in size like a cul de sac
o Extends to just behind the equator of the eyeball
o It is 14mm from the lateral limbus and about 5mm
from the lateral canthus
oMedial
o It is a shallow cul de sac in which lie the caruncle
and plica seminlunaris dipped in pool of tears
called as tear lake

Structure of conjunctiva
Histologically cornea consists of 3 layers
Conjunctiva
Epithelium
Adenoid layer
Fibrous layer

 Epithelium
a. The layers of epithelial cells in the conjunctiva vary
from region to region and its different parts are
oMarginal conjunctiva-
oHave 5 layers non keratinised stratified
squamous type of epithelium
oSuperficial layer- squamous cell
oIntermediate 3 layers- polyhedral cells
oDeepest layer- goblet cells

oTarsal conjunctiva-
oHas 2 layer epithelium in the upper eyelid
oSuperficial layer- cylindrical cells
oDeep layers- cubical cells
oLower tarsal conjunctiva is made of 3-4
layers of cells like the cubical, polygonal,
elongated wedge shaped and cone shaped
cells

The
Epithelium
The
Adenoid
Layer
The
Fibrous
Layer
The
Epithelium

oFornix and bulbar conjunctiva
o3 layered epithelium
oSuperficial layer- cylindrical ells
oMiddle layer- polyhedral cells
oDeep layer- cuboidal cells

oLimbal conjunctiva
o8-10 layers of stratified squamous
epithelium
oMost superficial 1-2 layers- squamous
cells
oIntermediate several layers- polygonal
cells
oBasal layer- cylindrical or cubicalcells

Cells Present In The Epithelium
oGoblet cells-
oPresent between the epithelial cells in all
regions of conjunctiva
oMelanocytes-
oFound in conjunctiva at limbus, fornix,
crancule and at the site of entry of anterior
ciliary vessels

Cells Present In The Epithelium,Cont
oLangerhans cells-
oPresent in all parts of conjunctiva
oConjunctival associated lymphoid tissue (
CALT)-
oConsists of T and B lymphocytes

d. Mucosal associated lymphoid
tissue(MALT)
o MALT of the gut and bronchi are also found in the
conjunctiva

Adenoid layer
o Also called as
lymphoid layer
o Consists of fine
connective tissue
reticulum in the
meshes of which lie
the lymphocytes
o Most developed in the
fornices and ends at the
subtarsal fold
o Develops after 2-3
months of life
The Adenoid Layer

oFibrous layer
o Consists of a meshwork of collagenous and elastic
fibres
o Thicker than the adenoid layer
o Except in the tarsal conjunctiva where it is very
thin
o This layer consist vessels and nerves of the
conjunctiva
o The adenoid layer and the fibrous layer are
collectively called as substantia propia

The
Epithelium
The
Adenoid
Layer
The
Fibrous
Layer
The fibrous
layer

Conjunctival glands
Mucin
secretory
glans
• Goblet cells
• Crypts of henle
• Glands of manz
Acessory
lacrimal
glands
• Glands of krause
• Glands
of
wolfring

o Goblet cells
o Round or oval in shape with
an eccentric flat nucleus
o Unicellular mucous cells
located abundantly within the
epithelium of all regions of
conjunctiva

o These cells are formed from the deepest cells of
the conjunctiva
o Once discharging their content- the mucin they
are destroyed
o Density is more in children
o than adults
o More in the bulbar conjunctiva and inferior
fornix

 Henle’s glands
o Not true glands but folds of mucous membrane
present in the palpebral conjunctiva
o These are tubular structures with lumina of 15-30
µm
 Glands of manz
o Found in limbal conjunctiva in animals

 Glands of krause
o Microscopic glands that lie in the sub conjuctival
tissue of the fornices
o These are about 40-42 in the upper fornix and
about 6-8 in the lower fornix
 Glands of wolfring
o Also called as the glands of Ciaccio
o These are microscopic glands present along the
upper border of superior tarsus and lower border
of inferior tarsus

Blood supply
Arteries supplying the conjunctiva are derived from
3 sources. They are:
1. Marginal arcade of the eyelid
2. Peripheral arterial arcade of the eyelid
3. Anterior ciliary artery

Blood supply,Cont
The palpebral conjunctiva and the fornices are supplied
by branches from the marginal and peripheral arcades of
the artery

 Bulbar conjunctiva is supplied by posterior conjunctival
arteries and anterior conjunctival arteries

Venous drainage
The veins from conjunctiva drain into the venous
plexus of eyelids which in turn drain into the superior
and inferior ophthalmic veins.

Venous drainage,Cont
A cicumcorneal zone of limbus drain into the
anterior cilliary veins

Lymphatic drainage
Lymphatics from the
lateral side drain into
the periauricular lymph
nodes
The lymphatics from
the medial side drain
the submandibular
lymph nodes

Nerve supply
A circumcorneal zone of the conjunctiva is supplied
from the long ciliary nerves.
Rest of the conjunctiva is supplied by the branches
from the lacrimal, infratrochlear, supratrochlear,
supraorbital and the frontal nevers

Conjunctival anatomy

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