The lacrimal apparatus is responsible for producing and draining tears. It consists of the lacrimal gland, conjunctival sac, lacrimal puncta, canaliculi, lacrimal sac, and nasolacrimal duct. The lacrimal gland produces tears which flush the conjunctival sac and nourish the cornea. Tears drain through the puncta and canaliculi into the lacrimal sac and then the nasolacrimal duct, which empties into the nose. Obstruction of the nasolacrimal duct can cause inflammation of the lacrimal sac due to retained tears.

1. Lacrimal Apparatus
DR.Chandra Philip.

2. Lacrimal
apparatus- It is
concerned with
production and
drainage of
lacrimal fluid

3. Components
1) Lacrimal
gland
2) Conjunctival
sac
3) Lacrimal puncta
with
canaliculi
4) Lacrimal sac
5) Nasolacrimal
duct

4. Lacrimal gland
Parts-
1) Upper part or
orbital part
2) Lower part or
palpebral part

6. • Situation
Orbital part-
Lateral part
of roof of
the orbit
Palpebral part-
lateral part
of the upper
eyelid

7. Ducts-
Gland has about one
dozen ducts which
open into the
superior
conjunctival fornix
Accessory lacrimal
glands- are present
in the conjunctival
fornices of both
the eyelids

8. • Histology
Compound tubuloalveolar type
of gland
1) Alveoli are lined by simple
columnar epithelium
showing two types of cells
a) G cells- mainly secrete
serous fluid
b) K cells – secrete mucus
fluid
2) Gland produces 1ml of
secretion per day
3) Secretion is alkaline in nature
rich in various salts and
lysozyme enzyme which is
bactericiidal in nature.

9. Functions of tears
1) Flush the conjuctival sac and keep the cornea
moist and transparent
2) It provides nourishment to the cornea
3) Bactericidal
4) One can express emotions with out break of
tears

10. Nerve supply
Sensory –
Lacrimal
nerve
Secretomotor-
from
parasympathe
tic nerves via
pterygopalati
ne ganglion.

11. Arterial supply-
Lacrimal artery
branch of
ophthalmic
artery.

12. • Conjunctival sac
Potential space
between eyelids
and eyeball is
known as
conjunctival sac
Conjuctival
fornices-
Line of reflexion
between bulbar
and palpebral
conjunctiva

14. Lacrimal canaliculi-
measures 10
mm in length.
1) Superior
canaliculi-
begins from the
lacrimal puncta,
passes upward
and then
downwards and
medially and
open into the
lacrimal sac

15. Inferior canaliculi
begins from
the puncta,
passes
downward
and then
horizontally
medialward
to reach the
lacrimal sac
At the bending
each
canaliculi
presents a
dilatation
known as
ampulla.

16. Lacrimal sac-
It is the upper blind end of
the nasolacrimal duct
situated in the lacrimal
fossa, formed by the
frontal process of the
maxilla and lacrimal
bone.
Boundaries-
Infront- Medial palpebral
ligament
Behind- Lacrimal part of
orbicularis oculi.
Laterally – lacrimal fascia
Medially- sac is separated
from bony fossa by an
arterial plexus derived
from terminal branches
of facial artery.

17. Nasolacrimal duct-
1) It is a
membranous
canal
measuring
about 18mm
in length
2) It begins from
the lower
end of
lacrimal sac
runs
downward
and opens
into the
inferior
meatus of
the nose

19. 3) The duct is
narrow in the
middle and
wide at both
the ends.
4) Lower opening
is guarded by
valve of Hasner
which prevents
air being
blown up the
duct into the
eye.

20. • Inflammation of
the lacrimal sac
due to
obstruction of the
nasolacrimal duct,
leading to
retention of
mucus and tears
in the sac .