1. SIVATEJA
CHALLA
ANATOMY OF THE LACRIMAL
APPARATUS

2. 1.Lacrimal gland
2.Lacrimal ducts
3.Conjunctival sac
4.Lacrimal puncta
5.Lacrimal canaliculi
6.Lacrimal sac and
7.Naso lacrimal duct

3. Embryology
Osteology
Secretory system
Excretory system

4. EMBRYOLOGY
DEVELOPMENT-LACRIMAL GLAND
 surface ectoderm
 Initially solid cords formed from supero lateral
conjunctiva,but by 3months central cells vacuolte and
lumina appear
 Full differentiation by 3-4 yrs postnatally
 Composed of ectodermal glandular units and
mesodermal myoepidermal cells and fibrous
tissue.
 Functions 6wks after birth.so no tears in new born
when crying.

5. DEVELOPMENT- LACRIMAL SAC & NASO LACRIMAL
DUCT
At junction of maxillary process and lateral nasal process a
mass of ectodermal cells submerge gets canalised to form
lacrimal sac and NLD. The lacrimal canaliculi
are extensions from the
lacrimal sac in to the
eyelid
 Non fusion of maxillary
and lateral processes
resuts in oblique facial
cleft and in such cases
NLD not formed

6. Fig. 6. Lacrimal drainage system embryology. A. At 5.5 weeks' gestation, an
ectodermal invagination forms between the lateral nasal process and
maxillary process,
which becomes pinched off from the surface. B. At 6 weeks' gestation, a solid
cord of ectoderm is located between the primitive medial canthus and nose.
C. At 12 weeks' gestation, proliferation of the cord occurs laterally toward the
eyelid and inferiorly toward the
inferior turbinate. The isolated cavities shown appear at3 to 4 months. D. At 7
months, canalization is nearly complete, with only the puncta and valve of

7. OSTEOLOGY
 The lacrimal sac fossa is a depression in the
inferomedial orbital rim,
 Maxillary and lacrimal bones.
 Bordered by the anterior lacrimal crest (maxillary
bone) & posterior lacrimal crest (lacrimal bone).
 The fossa is approximately 16-mm high, 4- to 9-
mm wide, and 2-mm deep.

9.  The medial orbital wall : Frontal process of
maxilla, lacrimal ,ethmoid , lesser wing of
sphenoid bone.
 The frontoethmoidal suture is important in
lacrimal surgery
 It marks the roof of the ethmoid sinus. Bony
dissection superior to this suture may expose the
dura of the cranial cavity.

10.  The nasolacrimal canal originates at base of
lacrimal fossa.
 Formed by the maxillary bone laterally and the
lacrimal and inferior turbinate bones medially.
 The width of superior opening is 4–6 mm.
 The duct courses posteriorly and laterally in the
bone for 12 mm to drain into the inferior meatus
of the nasal cavity.

11. SECRETORY SYSTEM
 It includes lacrimal gland, accessory glands
 Lacrimal gland is above & anterolateral to globe.
 Secretes tears into superior fornix.
 Tears moisten & lubricates the : cornea ,
conjunctiva.

12. LACRIMAL GLAND
DEVELOPMENT
 Develops from surface ectoderm
 Develops as epithelial bud evaginating from basal
cells of conjunctiva in supratemporal portion of
embryonic fornix
 Initially solid cords formed,but by 3months central cells
vacuolte and lumina appear
 Full differentiation by 3-4 yrs postnatally
 Composed of ectodermal glandular units and
mesodermal myoepidermal cells and fibrous
tissue.
 Functions 6wks after birth.so no tears in new born
when crying.

13. ANATOMY
 Located in anterolateral
part of the roof of orbit
in fossa for lacrimal
gland
 Divided in to large
superficial orbital part
and small deep
palpebral part which
are continuous with
each other around
aponeurosis of LPS

14. ORBITAL PART
Almond shaped
Two surfaces (superior and inferior) two borders
(anterior and posterior and two extremities (medial
and lateral)
superior surface convex and related to orbit roof
Inferior surface concave and related to LPS
Anterior border limited by orbital septum
Posterior border related to orbital pad of fat
Medial extremity related to LPS
Lateral extremity rests on lateral rectus

15. PALPEBRAL PART
1/3RD size of orbital part
Superiorly related to
LPS and inferiorly to
superior fornix
When lid is everted the
gland can be seen in
superior fornix of
conjunctiva

16. ANCHORS
1.Above by suspensory ligament
2.Below by fibrous attachment to the zygomatic bone
3.Behind by fascial condensation around lacrimal
nerves and vessels
4.Internally by fascial expansion of ocular muscles

17. LACRIMAL DUCTS
 10-12 ducts
 Ducts arising from the orbital part passes through
palpebral part and opens in to superior fornix of
conjunctiva
 Additional ducts from palpebral part open directly in
to conjunctiva
 Removal or damage to palpebral part of the gland
will stop secrections reaching the fornix
 So biopsy of gland always done in orbital part of
lobe

18. STRUCTURE OF LACRIMAL GLAND
Lobulated tubulo acinar gland
Microscopically has Glandular tissue,Stroma and
Septa
-Glandular tissue consists of
acini and ducts arranged in
lobes and lobules seperated by
Septa
-acini has pyramidal cells which
secrete the tears expelled by the
contraction of myofibrils
-Stroma formed by mesodermal
tissue which has connective
tissue,lymphoid cells,plasma
cells,rich nerve terminals and

19. BLOOD SUPPLY-
Internal carotid artery Angular vein
Ophthalmic artery Superior
ophthalmic vein
Lacrimal artery Lacrimal vein
Some times by infraorbital artery(Br of maxillary artery)
LYMPHATIC DRAINAGE-
Pre auricular group

20. NERVE SUPPLY
 Parasympathetic secretomotor fibres(efferent) from
superior salivatory nucleus
 Sympathetic nerve supply from carotid plexus
 Sensory supply(afferent) from lacrimal nerve Br of
ophthalmic division of fifth nerve

21. EXCRETORY SYSTEM

22. CONJUNCTIVAL SAC
 Conjunctiva stretches from lid margin to limbus
and encloses a potential space conjunctival sac
which opens at palpebral fissure
 Sac is closed only when lids are approximated

23. LACRIMAL PUNCTA
 Two puncta situated in
each lid margin at the
junction of ciliary and
lacrimal parts on
elevtion called lacrimal
papilla
 Upper punctum 6mm
and lower 6.5 mm from
medium canthus
 Surrounded by fibrous
tissue which keeps them
patent

24. LACRIMAL CANALICULI
 2 in number,Joins puncta to lacrimal sac
 Two parts vertical(2mm) and horizontal(8mm) at
junction dilated to form ampulla
 Pierce lacrimal fascia and unite to form common
canaliculi opens in to lacrimal sinus of maier
 At opening in to sac protected by valve of
rosenmuller
 Surrounded by fibres of pars lacrimalis of orbicularis
oculi muscle
 During blink canaliculi pulled medially,shortened and
compressed by pars lacrimalis.also helps in dilatation
of lacrimal sac

25. LACRIMAL SAC
 Upper expanded portion of
NLD
 Lodged in lacrimal fossa(medial
wall is lamina
papyracea,formed by lacrimal
bone and frontal process of
maxilla)
 Surrounded by lacrimal fascia
which results from splitting of
periorbita
 Between sac and fascia are
venous plexus
 Part of sac above MPL is
fundus.At junction of fundus

26.  RELATIONS
Anteriorly to medial palpebral ligament
Posteriorly to posterior lacrimal crest and orbicularis
oculi
Medially to middle meatus and ant ethmoidal sinus
Laterally to skin,fascia and orbicularis oculi(lacrimal
part)
ANGULAR VEIN and ANGULAR ARETRY crosses
MPL about 8mm from the medial canthus.many times
a tributary runs 3mm from medial canthus.so to avoid
profuse bleeding during sac surgery incison should
be made within 3mm medial to medial canthus

28.  Extends from lacrimal
sac to inferior meatus of
nose
 18 mm in length and
3mm diameter
 Upper end is the
narrowest
 Runs
downward,backward
and laterally
 Lined by two layers of
coloumnar epithelium
 Has intraosseus and
intra mural part
NASO LACRIMAL DUCT

29.  Intraosseus part lodged in naso lacrimal Canal
formed by maxilla anterolaterally,lacrimal bone
and inferior nasal concha postero medially
 Intramural part variable in length and lies in inferior
meatus.
 NLD opens below in to anterior part of inferior
meatus.
 opening guarded by a fold of mucosa-valve of
hasner.prevents air from entering the sac when air
blown out of closed nose
 In infants some times canalisation is delayed or do
not occur causing epiphora and cong dacrocystitis
 Duct is surrounded by rich plexus of veins,forming a
erectile tissue .engorgement leads to obstruction of
NLD and epiphora

30. BLOOD SUPPLY
ARTERIAL SUPPLY
Superior and inferior palpebral
A.
Angular A.
Infraorbital A.
Nasal br. Of sphenopalatine A.
VENOUS DRIANAGE
Angular vein
Infraorbital vein
Nasal vein
LYMPHATICS
Sub mandibular group
Deep cervical group
NERVE SUPPLY
Infra trochlear nerve
Anterior superior alveolar N.

31. ELIMINATION OF TEARS
 Lacrimal fluid over the preocular surfacemarginal
tear stripLacus lacrimalisinner canthus lacrimal
passages  nasal cavity
 Lacrimal pump mechanism:- fibres of the pretarsal &
preseptal portion of the Orbicularis which arise from
the lacrimal fascia & posterior lacrimal crest.
 This LPM operates with the blinking movements of
the eyelids as follows:-

35. DRAINAGE OF LACRIMAL FLUID FROM NLD INTO
NASAL CAVITY
 Gravity helps downward flow.
 Air currents in nose induce negative pressure within
NLD draw the fluid down the potential lumen of the
duct into the nose.
 Hasner’s valve present at lower end of NLD, remains
open as long as the pressure within nose is less than
the NLD, allows the tears to flow from NLD to nose

36. THANK YOU