Lacrimal appartus

1. LACRIMAL APPARATUS

Secretory Portion 
Excretory portion

2. Secretory Portion
Accessory Lacrimal glands (see before)
=> Basic secretion
Main lacrimai gland => Reflex secretion.

3. Gross
Anatomy
o Size: 20 X 12 X 5 mm
o Weight: 75 gm
o Portions:
the gland is devided by the lateral part
of levator aponeurosis into:

4. orbital portion
Size : Small
Site:
Lacrimal gland fossa (in the anterior
lateral part of the orbital roof)
Shape
Almond shaped
Superior surface —> convex
lies in the fossa connected to it by
weak trabeculae
Inferior surface —> concave
lies on the levator aponeurosis & LR
Anterior border —> Sharp
in contact with the orbital septum
(reached by division of skin.
Orbicularis oculi & orbital
septum)
Posterior border —> Rounded in
contact with orbital fat
Medial extremity —» rests on levator
Lateral extremity -> rests on LR

5. Palpepral portion
Smaller (1/3 of the orbital
portion)
In the lateral part of upper
eyelid
(can be seen through the
conjunctiva when the
upper lid is everted
Flattened from above
downwards
Anterior border —» lies just
above the lateral part of
the superior fornix.
Posterior border —>
continuous with the rest
of the gland around the
lateral border of the
levator aponeurosis.

6. Ducts:
3-5 ducts pass from the
orbital portion through the
palpebral portion to open
into the superior fornix.
5-7 ducts from the palpebral
portion open separately
into the superior fornix -»
So, surgical removal of
the palpebral part will
destroy the whole gland.

7. Structure:
Tubulo-alveolar (tubulo-aciner) gland
Consist of lobules (each about the size of pin
head) formed of:
numerous Acini (composed of a double layers of
cells resting on B.M)
1. outer myoepithelial contractile cells
2. inner secretory cylindrical cells
3. surrounding a central canal
4. open into larger ducts (intralobular then
interlobular ducts)
5. open into excretory ducts
(lined by columnar epithelium & have a fibrous
coat)

8. Intralobular (between acini) & interlobular
(between lobules) C.T reticulum is
present containing Blood vessels, Nerve
fibers, Plasma cells & lymphocytes
(aggregate into follicles)

9. Ligaments & support:
• Superior —> to the lacrimal fossa
= suspensory ligament
• Inferior pole —> to zygomatic
bone
• Posterior —> where lacrimal
nerve & vessels enter the
periorbita
• Internally accompanying the
ducts.

10. Blood supply:
o Arterial -> Lacrimal
artery (enters the
posterior border of
the gland)
o Venous —>
Corresponding vein
join the ophthalmic
vein
o Lymphatic —>
Conjunctival
lymphatics —» Pre-
auricular LNs

11. Function:
Tears Secretion (mainly the reflex secretion)
(Moisting the eye - Prevent friction
between globe & lids - Keep the cornea
transparent)

12. Nerve supply:
1. Parasympathatic
2. Sympathatic
3. Sensory

13. A. Parasympathetic
lacrimal (Superior salivalory
nucleus of the facial n.) (N
VII) in the floor of the 4th
ventricle)
Preganglionic fibers extends
with facial n.(nervus
intermedius part)
geniculate ganglion (no relay)
greater superficial petrosal n.
nerve of pterygoid canal
sphenopalatine ganglion
(synapse)
postganglionic parasvmpatheic
fibers Join maxilary n. (of
trigeminal)
Zygomatico-temporal branch
Lacrimal n.
Lacrimal Gland. (Vasomotor)

14. B. Sympathetic
Superior cervical sympathetic
ganglion
Postganglionic fibers accompany
I.C.A.
Deep petrosal n.
nerve of pterygoid canal‘
sphenopalatine ganglion(no relay)
postganglionic sympatheic fibers
Join maxilary n. (of trigeminal)
Zygomatico-temporal branch
Lacrimal n.
Lacrimal Gland.

15. C. Sensory:! -> Lacrimal nerve.

16. Excretory Portion
Puncta:
• Shape: slightly elevated,
rounded or slightly oval
openings
• Diameter: About 0.3 mm
• Site: on the upper & lower
eyelid margins (at the
junction of the ciliary &
lacrimal portions), on the
papilla lacrimalis, about
6mm (upper) — 6.5mm
(lower) from the medial
canthus

17. • The puncta openings of the lacrimal canaliculi
are inverted into the lacrimal lake when the
eyelids are closed.
• The puncta are surrounded by:
- Dense, Fibrous, relatively avascular C.T. —>
Prevents their collapse + gives the pale colour
- Orbicularis oculi muscle —> Helps tear
drainage
How to know its site ? => 6 mm from the medial
canthus + 0.5 mm from the tarsal gland +
elevated + paler (avascular)

18. Canaliculi:
• The upper and lower
canaliculi consist of:
o vertical portion about 2-
3.5 mm
o horizontal portion about
8 mm (directed medially) =>
two join to Form, the
common canaliculus —>
opens in the lacrimal sinus of
Maier
• Diameter: About 0.5 mm.
• Site:Lacrimal portion of the
lid margin.
• Structure & surroundings:
o Lined by stratified
squamous epithelium.
o Surrounded by elastic
tissue then orbicularis
fibers. (Homer's muscle)

19. Lacrimal sac:
• Site: lacrimal fossa (in the anterior
part of the medial orbital wall),
between:
1. the anterior lacrimal crest of the
frontal process of the maxilla.
2. the posterior lacrimal crest of the
lacrimal bone.
Dimentions; 15 X 5 X 5 (When
distended)
• Parts: Fundus (above M.P.L)
Body (behind M.P.L) Neck
(continuous with NLD)
• Lateral sinus of Maier: is a diverticulum
that arise just behind the middle of the
lateral surface (2.5 mm from the apex)
—» in which open the canaliculi.

20. Structure:
A. Sac: Lined by 2 layers of columnar cells with
goblet cells, surrounded by fibro-elastic CT
B. Lacrimal fascia:
o Formed by splitting of the periorbita into 2
layers at the posterior lacrimal crest —>
enclose the sac —> meet again at the anterior
lacrimal crest.
o Venous plexus is present between the
lacrimal sac & lacrimal fascia (continuous with
that around the duct)

21. Nasolacrirmal duct:
• Definition: A downward extension of
the neck of lacrimal sac till the inferior
nasal meatus (at the anterior portion of
the lateral wall) (lateral to & below the
inferior turbinate)
• Length: 15-18 mm
• Site:
o In the bone of the nasolacrimal canal
=> formed by a groove on the maxilla &
completed by lacrimal bone & lacrimal
process
of inferior concha => The duct is loosely
adherent to the canal above, but
strongly adherent below —>
mucoperiosteum (infection is easily
transmitted from bone to duct & vice
versa)
o The duct may pass for millimeters in
the nasal mucous membrane before its
opening
• Direction: Downwards, Laterally &
posteriorly (Massage -> stretch &
press down laterally & little back)

22. Valves: numerous mucous membrane folds,
not valvular in function
Hasner's valve (guards the opening of the
NLD) —> prevent sudden blast of air from
nose to the sac as during blowing the nose
into a handkerchief)

23. • Structure:
o Epithelium: 2 layers
• Superficial columnar (reach the BM through
deep cells) with goblet cells & mucous
glands.
. Deep flattened.
o Subepithelial layer: contains lymphocytes
o Fibroelastic membranous wall
o Dense vascular erectile venous plexus
surrounding the duct (engorgement -» duct
obstruction)

24. • Relations;
o Laterally => Maxillary antrum
o Medially => Middle meatus of the nose
• Blood supply:
o Arteries —> Medial palpebral a. Angular a.
Infraorbital a. Nasal br. of sphenopalatine
o Veins —> Angular v. & Infraorbital v. (above)
Nasal veins (below)
• Lymphatic supply; -> Submandibular LNs
• Nerve supply:
o Infratrochlear n. (branch of ophthalmic) _
o Anterior superior alveolar n. (branch of
maxillary)