This document describes the anatomy and structure of the lacrimal apparatus, which produces and drains tears from the eyes. It includes the main lacrimal gland located in the orbit, accessory lacrimal glands in the eyelid, and the lacrimal drainage system consisting of puncta, canaliculi, lacrimal sac, and nasolacrimal duct leading to the nose. The main lacrimal gland is a serous gland made of acini and ducts and receives blood supply from the lacrimal artery and drains to the ophthalmic vein. Tears produced drain through puncta and canaliculi into the lacrimal sac then through the nasolacrimal duct to

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LACRIMAL
APPARATUS
By DR.SAVITHA
1ST year ophthalmology

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CONTENTS
Lacrimal apparatus:
 Main lacrimal gland
 Accesory lacrimal
gland
 And it’s transport
Location : fossa by
orbital plate of frontal
bone.

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Main lacrimal gland
 aponeurosis of the levator
muscle
 Superior- orbital
size of small almond
 Inferior- palpebral
1/3 rd of orbital part
consists of only two or three
lobules

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Orbital part of main lacrimal gland
 Orbital part
 2-surfaces-superior n inferior
 2 - border-anterior n posterior
 2- extremity –medial n lateral
 Superior surface of the orbital part –
convex, periorbita - part of the frontal
bone forming the fossa for the lacrimal
gland. by fine trabeculae.
 Inferior surface of the orbital part –
concave- on the levator palpebrae
superioris muscle and the lateral horn of
the levator aponeurosis.

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Orbital part of lacrimal gland
• Anterior border - sharp and in contact with the septum orbitale.
• Posterior border - round and in contact with the orbital pad of fat.
. Lateral extremity -on the lateral rectus
muscle.
.Medial extremity - to the levator palpebrae superioris muscle

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DUCTS OF LACRIMAL GLAND
Ducts of lacrimal gland:
10-12 ducts - main lacrimal gland -
open in the lateral part of the superior
fornix.
One or two ducts -open in the lateral
part of the inferior fornix.
all the ducts pass through the
palpebral part of the gland-excision of
the palpebral part alone is enough to
stop secretory function.

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Histological structure of the lacrimal gland
 tubuloalveolar (serous
acinous) gland
 glandular tissue, stroma and
septa
 Acini -pyramidal cells-
secrete tears expelled by
contraction of myofibrils
 Ductules:intralobular and
extralobular
 Stroma of the lacrimal gland -
connective tissue, elastic
tissue,lymphoid tissue, plasma
cells, rich nerve terminals and
blood vessels

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Main lacrimal gland vessels
Blood supply :
 lacrimal artery, a branch of ophthalmic artery (branch of the transverse facial artery )
 Lacrimal veins -ophthalmic vein.
 Lymphatic drainage-preauricular lymph nodes

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NERVES of main lacrimal gland
Main lacrimal gland has three modes of innervations (Fig. 10.10):
1. Sensory nerve supply comes from the lacrimal nerve, a branch of ophthalmic division
of the fifth cranial nerve.
2. Sympathetic nerve supply arises from the superior cervical sympathetic ganglion as
postganglionic fibres which from the carotid plexus of the cervical sympathetics. From
the sympathetic plexus around the internal carotid artery, some fibres join the deep
petrosal nerve, then the nerve of pterygoid gland, and then ultimately reach the lacrimal
gland through the lacrimal nerve branch of V1 (Fig. 10.10).
3. Secretomotor fibres are derived from the superior salivary nucleus. The course of the
nerve fibres reaching the lacrimal gland in summarized in Fig. 10.10. For details, see
page 566.Accessory lacrimal glands

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ACCESSORY LACRIMAL GLANDS
• Glands of Krause
•Glands of Wolfring
• Intraorbital glands
.Glands in the caruncle and plica semilunaris-rudimentary
1.Glands of Krause-subconjunctival tissue of the fronices.
40-42 in the upper fornix
6-8 in the lower fornix.
opens in the fornix.
2.Glands of Wolfring
upper border of superior tarsus (2-5 in number)
lower border of inferior tarsus (2-3 in number)

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LCARIMAL PASSAGES:PUNCTA
1. Lacrimal puncta:
 papilla.
 upper puncta-6 mm and Lower
puncta -6.5 mm lateral to the
inner canthus
 upper punctum-downwards and
backwards
 lower punctum -upwards and
backward.

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LACRIMAL PASSAGES:CANALICULI
2. Lacrimal canaliculi
Each canaliculus is 0.5 mm - vertical (2 mm) and
horizontal (8 mm),
at right angle
ampulla.
Pierce lacrimal fascia
lacrimal sinus of Maier.
In about 10% individuals, each canaliculus enters the
sac separately.
Structure:
 Epithelium -stratifiedsquamous type.
 Corium rich in elastic tissue,-dilated to about 2 mm
(normal diameter 0.5 mm) while passing a probe.
 Fibres of orbicularis -pars lacrimalis. draw the lid
inward-puncta to glide in the groove between the
plica semilunaris and the eyeball.

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LACRIMAL PASSAGES:SAC
3. Lacrimal sac
 lacrimal fossa -lacrimal bone and
frontal process of the maxilla.
 Lacrimal fascia-The periorbita
(periosteum lining the orbit).Between
the lacrimal sac and the fascia lie
alveolar tissue and venous plexus
which is continuous around the
nasolacrimal duct.
 Dimension. The lacrimal sac when
distended is about 15 mm in length
and 5-6 mm in breadth with a
capacity (volume) of about 20 cm
 Parts:fundus,body,neck

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Relations of the lacrimal sac
1.Medially:anterior ethmoidal sinus in the upper part and middle meatus of the nose in the lower part.
2.Anterolateral relations of the sac from deep to superficial include :
 Lacrimal fascia and few fibres of the inferior oblique muscle which arise from it.
 Lacrimal fibres of the orbicularis muscle(Homer’s muscle).
 Medial palpebral ligament-covers only the upper part of the sac.distension -occurs in lower part. Lacrimal abscess
and fistula also open in the lower part owing to less resistance.
 Palpebral fibres of orbicularis.
 Angular vein which crosses the medial palpebral ligament about 8 mm from the medial canthus. Many a time a tributary
of the Angular vein runs between it and the medial canthus. Therefore, to avoid profuse bleeding during sac surgery,
the incision should not be made more than 3 mm medial to the medial canthus.
 Skin
3. Posteriorly:anterior to posterior important structures are:
• Lacrimal fascia.
• Fibres of lacrimal part of orbicularis. Septum orbitale which separates the sac from the orbital fat and check ligament of the
medial rectus muscle.

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LACRIMAL PASSAGES:NLD
4. Nasolacrimal duct (NLD):
 inferior meatus of the nose
 18 mm (may vary from 12-24 mm) in length
 3 mm in diameter.
 Direction of the NLD is downwards, backwards and laterally
 2 PARTS:intraosseous part (12.5 mm) : anterolaterally by the Maxilla and posteromedially by the
lacrimal and inferior nasal concha. The nasolacrimal canal lies lateral to middle meatus and produces
a ridge in the maxillary antrum; therefore, lesions of the maxillary sinus often cause epiphora.
 intrameatal part (5.5 mm).-The opening of the NLD in the inferior meatus is situated at a depth of
about 30-40 mm from the anterior nares.
 The lumen of the NLD has valve of Hasner situated at its lower end. It prevents the entry of the air
into the lacrimal sac, when air is blown out of a closed nose.
 In the fetus, the NLD is a solid cord of cells, which gets canalised later. In about 30% of the newborn
infants, the canalization is delayed or does not occur at its lower end near the valve of Hasner. This
congenital NLD blockage causes epiphora and may predispose to congenital dacryocystitis.

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Structure of lacrimal sac and duct
1. Epithelium: superficial layer is of non-ciliated columnar cells and contains goblet cells. deep layer is of
flattened cells.
2.Subepithelial tissue c- lymphocytes which may aggregate in pathological condition to form follicles.
3.Fibroelastic tissue
4. Plexus of vessels--Engorgement of these vessels is said to be sufficient to cause obstruction of the
NLD and produce epiphora.
Blood supply of the lacrimal passages
Arterial supply -superior and inferior palpebral arteries (branches of ophthalmic artery), angular artery,
infraorbital artery and nasal branches of sphenopalatine artery.
Venous drainage- angular vein and infraorbital vein from above and into the nasal vein from below.
Lymphatics drain -submandibular and the deep cervical glands.
Nerve supply
Sensory nerve supply to the lacrimal sac and NLD comes from the infratrochlear nerve and the anterior
superior alveolar nerves.Probably, there is a reflex relation between the nerve supply of the lacrimal
gland and the lacrimal sac, because extirpation of the latter greatly diminishes the tear production.