Anatomy of Conjunctiva- bulbar ,palpebral and forniceal

The conjunctiva can be divided into three regions: the palpebral or tarsal conjunctiva, the bulbar or ocular conjunctiva, and the conjunctival fornices. The palpebral conjunctiva is further divided into the marginal, tarsal, and orbital regions. The bulbar conjunctiva is divided into scleral and limbal parts.
The conjunctiva is the mucous membrane of the eye. It lines the inner surfaces of the eyelids or palpebræ, and is reflected over the forepart of the sclera and cornea.

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.

The Palpebral conjunctiva (Palpebral Portion) is thick, opaque, highly vascular, and covered with numerous papillæ, its deeper part presenting a considerable amount of lymphoid tissue. At the margins of the lids it becomes continuous with the lining membrane of the ducts of the tarsal glands, and, through the lacrimal ducts, with the lining membrane of the lacrimal sac and nasolacrimal duct. At the lateral angle of the upper eyelid the ducts of the lacrimal gland open on its free surface; and at the medial angle it forms a semilunar fold, the plica semilunaris. The line of reflection of the conjunctiva from the upper eyelid on to the bulb of the eye is named the superior fornix, and that from the lower lid the inferior fornix.

The bulbar conjunctiva (Bulbar Portion)- Upon the sclera, the conjunctiva is loosely connected to the bulb of the eye; it is thin, transparent, destitute of papillæ, and only slightly vascular. Upon the cornea, the conjunctiva consists only of epithelium, constituting the epithelium of the cornea. Lymphatics arise in the conjunctiva in a delicate zone around the cornea, and run to the ocular conjunctiva.

The histology of conjunctiva consists of non-keratinized, stratified squamous epithelium, with interspersed goblet cells. The epithelial layer contains blood vessels, fibrous tissue, and lymphatic channels. Accessory lacrimal glands in the conjunctiva constantly produce the aqueous portion of tears. Additional cells present in the conjunctival epithelium include melanocytes, T and B cell lymphocytes.
The conjunctiva is the mucous membrane of the eye. It lines the inner surfaces of the eyelids or palpebræ, and is reflected over the forepart of the sclera and cornea.

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.

The Palpebral conjunctiva (Palpebral Portion) is thick, opaque, highly vascular, and covered with numerous papillæ, its deeper part presenting a considerable amount of lymphoid tissue. At the margins of the lids it becomes continuous with the lining membrane of the ducts of the tarsal glands, and, through the lacrimal ducts

1. Anatomy Of Conjunctiva

2. CONJUNCTIVA
Covers the lid
posteriorly
Reflected anteriorly
on the sclera.
Becomes continuous
with corneal
epithelium.

4. Palpabral Conjunctiva
Marginal
Tarsal
Orbital

5. Transitional zone between skin and the
conjunctiva proper.
Extends from the lid margin to about 2 mm
on the back of the lid.
Ends at the sulcus subtarsalis.( a shallow
groove at which the perforating vessels
traversethe tarsus to conjunctiva).
Common site for lodgement of foreign
body.
Marginal conjunctiva

6. Tarsal conjunctiva
Thin
Transparent
Adherent
Highly vascular(reddish colour).
Through this tarsal glands appear as yellow streaks
Common site for follicles, papillae and concretions.

7. Orbital conjunctiva
Between tarsal upper border and fornix.
Loosely attached to sub adjacent Muller’s muscle.
Horizontal folds-
Formed by movements
Maximum when eyes are open.
Least when eyes are closed.

8. Bulbar conjunctiva
Thin, translucent: underlying sclera thus appears
white.
Tied to subjacent structure by areolar tissue-mobile
enough to allow ocular movements.
Subconjunctival vessels and the anterior ciliary
arteries forming the pericorneal plexus can be seen.
Site to see
Icterus
Bitot`s spots.

9. Bulbar conjunctiva contd..
At about 3 mm from the cornea , conjunctiva ,
tenon’s and episcleral tissue are fused into a dense
tissue which is strongly adherent to underlying
corneo-scleral junction. Here the mobility is less.
At this union some times a slight ridge is seen called
limbal conjunctiva.
Preferred site for obtaining a firm hold during ocular
surgery.

10. Conjunctival Fornix
Superior fornix
Inferior fornix
Lateral fornix
Medial fornix

11. Conjunctival fornix
Dimensions in mm of
human conjunctival sac
measured from lid
margins with the
palpebral aperture
open.
Dimensions in mm of
human conjunctival sac
measured from the
limbus.

12. Superior forniceal conjunctiva
Adherent to areolar tissue,which is
continuous with expansions from the sheaths
of the levator and rectus muscles-
contractions can therefore deepen the
fornices.
Contains-gland of krause and palpebral
muscle of muller.
Well vascularized.

13. Forniceal conjunctiva
Adjoins orbital fat thus hemorrhage from a
basal cranial fracture can advance under the
conjunctiva to the limbus.
Incision at the superior fornix enter between
levator and superior rectus.
Foreign body lodged can be seen after
double eversion of upper lid

14. Inferior fornix-The extension of the
fascial sheath of the inferior rectus and
inferior oblique muscles is attached to
the conjunctival fold in the lower fornix.
Lateral fornix-Small cull de sac
extends just behind the equator.
Medial fornix-Here lies the caruncle
and plica semilunaris in the pool of
tears called lacus lacrimalis.

15. The caruncle
caruncle
Plica semilunaris

16. Caruncle
Caruncle {latin caro means flesh}
Soft pink ovoid body 5mm high 3mm
broad.
It is a piece of modified skin ( contains
sweat glands, sebaceous glands and
hair follicles) , differs from skin as it
contains glands of krause, goblet cells
and absence of keratinization.

17. Plica Semilunaris
Pinkish fold of conjunctiva present in
the medial canthus.
Vestigeal structure in human beings
and represents the nictitating
membrane.

18. Conjunctiva : structure
Broadly consist
of two layers
Epithelium
Submucosal
lamina propria
Lymphoid
layer (adenoid
layer).
Fibrous layer.
Epithelium
Lymphoid layer
(adenoid layer).
Fibrous layer.

19. Conjunctiva : Adenoid layer
Fine connective tissue reticulum containing
many lymphocytes
Thickest in the fornix and ends at the
subtarsal fold .
Not present since birth
Developed at 3-4 month of life
clinical importance
Follicles are not found in new borns

20. Conjunctiva : Fibrous layer
Consist of a meshwork of collagenous and
elastic fibers
Thicker than the adenoid layer except in the
region of the tarsal conjunctiva.
Contains conjunctival vessels , nerves and
glands of krause.

21. Specific cells
Goblet cells.
Mucin secreting cells .
Arising from the basal layer of the epithelium.
Occurs through out conjunctiva specially plica
semilunaris.
Contained in crypts of Henle.

22. Specific cells
Goblet cells.
Most dense nasally ,
Least dense in upper temporal fornix
Absent at the palpebral mucocutaneous
junction and limbus.
Chief source of tear mucin
number decreases with
age,
dry eye
vitamin A deficiency

23. Specific cells
Melanocytes
Occur at the limbusfornix , plica,
caruncle, and at sites of perforation of
anterior ciliaryvessels.
Langerhanscells
Part of the dendriticsystem.
Involved in allograft rejection of
conjunctiva

24. Accessory lacrimal gland
Glands of krause
Present in
subconjunctival
connective tissue of
fornix about 42 in upper
fornix and 6-8 in lower
fornix.
Glands of wolfring
Present along the upper
border of superior tarsus
and lower border of
inferior tarsus (2-5).

25. Arterial supply
Peripheral tarsal arcades
Marginal tarsal arcades
Anterior ciliary arteries
Deep ciliary system.

26. Peripheral tarsal arcades
Section of the upper lid and the anterior
portion of the eye to show the blood supply
to the conjunctiva

27. Tarsal arcades
Derived from medial and lateral palpebral
arteries , which are branches of ophthalmic
and lacrimal arteries.
Branches of the arcade supply the
orbicularis
skin
conjunctiva
tarsal glands.

29. Peripheral tarsal
arcades
Runs at the upper border of the tarsus between
the two parts of the levator.
Its peripheral perforating branches pierce the
palpebral muscles and divide into
ascending conjunctival branches
become posterior conjunctival arteries
descending conjunctival branches
supply the proximal 2/3 of tarsal
conjunctiva.

30. Marginal arcade
Send perforating branches through the
tarsus to the marginal conjunctiva.
Divide into marginal and tarsal twigs to meet
with the corresponding branches of the
peripheral arcade.

31. Anterior ciliary arteries
Derived from muscular arteries of the recti
They give rise to episcleral arteries which
enters the bulbar conjunctiva as the anterior
conjunctival arteries
anterior conjunctival arteries anastamose
with the posterior conjunctival arteries about
4 mm from limbus

32. Deep ciliary system
Derived from long posterior ciliary arteries.
This system communicates through
perforating scleral arteries with the
superficial episcleral arterial circle.

33. Superficial
conjunctival
congestion
More marked in the
fornices.
Bright red colour
Vessels move with
conjunctiva
Direction of flow from
fornix towards limbus
1:1000 epinephrine
leads to blanching
Deep ciliary
congestion
More marked around the
limbus
Purple colour
Vessels do not move.
Direction from limbus
towards fornices
1:1000 epinephrine do
not blanch

34. Venous drainage
Conjunctival veins are more numerous than
arteries.
Accompany the corresponding arteries
They dilate in hyperemia.

35. Venous drainage
Muscular veins
Ophthalmic vein
Venous plexus between
levator tendons
Conjunctival veins
Palpebral, forniceal and posterior
bulbar conjunctiva
Palpebral veins

36. Venous drainage
Ophthalmic veins
Muscular veins
Conjunctival veins
anterior
bulbar conjunctiva
Radial episcleral
collecting veins

37. Lymphatic drainage
Superficial plexus
(small lymphatics placed below the capillaries )
Deep plexus
(larger lymphatics in fibrous layer of conjunctiva)
Lateral canthus
Medial canthus
Preauricular
lymph nodes
Submandibular
lymph nodes

39. Nerve supply
From 1
st
division of fifth cranial nerve
Peripheral part
Infra-trochlear branch of nasocilliary
nerve
Lacrimal nerve
Supra and infra trochlear branches of
frontal nerve.
Infra orbital nerve.
Limbal area
Long ciliary nerve

41. Nerve supply
Free nerve endingsform
a subepithilial plexus in the substantia
propria.
an intra epithelial plexus around the bases
of epithelial cells and send free nerve
fibrils between the epithelial cells.