2. ANATOMY:
• Formation of tears : Main and accessory lacrimal glands
• Transport : Lacrimal passages
Lacrimal Gland :
• Situated in the fossa for lacrimal gland at the anterolateral part of roof of orbit
formed by orbital plate of frontal bone
3.
4. Anterior Posterior
Lat.horn of LPS
Superior orbital Inferior palpebral
- Superior surface - Two or three lobules
- Inferior surface - Superiorly Orbital part
- Anterior border - Inferiorly superior fornix
- Posterior border - Can be seen through conjun
- Lateral extremity ctiva when lid is everted
- Medial extremity
5.
6.
7. Ducts :
• 10-12 ducts open into lateral part of superior
fornix
• 1-2 ducts open into lateral part of inferior
• All ducts pass through palpebral part of gland
• Therefore excision of palpebral part alone
amounts to excision of whole gland
Histology :
• Branched tubuloalveolar (serous acinous )
similar to salivary gland
• Has Glandular tissue , Stroma and septae
• Glandular tissue has acini and ducts
8. - Acini are arranged in lobes and lobules separated by fibro
vascular septae
Pyramidal cells Myoepithelial cells
- single layer - expel tears
- secrete tears
Ductules( intralobular
and extra lobular )
Ducts
9. - Stroma has connective tissue , elastic and lymphoid tissue ,
plasma cells , rich nerve terminals and blood vessels
Blood supply :
- Lacrimal A. branch of ophthalmic A.
- Sometimes branch of transverse facial A.
- Lacrimal V. drain into Ophthalmic V.
Lymphatic drainage :
along with conjuctival drainage into
preauricular lymph nodes
10. Nerve supply :
Sensory – Lacrimal branch of ophthalmic N.
Sympathetic – Superior cervical sym. Ganglion
plexus around ICA
Deep petrosal N.
N. of pterygoid canal
Lacrimal gland
Secretomotor – Superior salivary nucleus
11. Accessory lacrimal glands :
Glands of Krause : at subconjunctival tissue of fornices
upper - 40 to 42
lower – 6 to 8
open into fornix
Glands of Wolfring : upper border of superior tarsus(2-5)
lower border of inferior tarsus(2-3)
Rudimentary : at caruncle , plica semilunaris and
infraorbital region
12.
13. Lacrimal passages :
Puncta : - at the junction of ciliary and lacrimal portions of
eyelid
- Situated on an elevation – lacrimal papillae
- Upper 6mm , lower 6.5mm from medial canthus
Canaliculi : - 0.5mm diameter
vertical ampulla horizontal
(2mm) (8mm)
common canaliculus
lacrimal sinus of Maier
lacrimal sac
14. Structures - inside to outside
• Epithelium : stratified squamous
• Corium : elastic tissue
• Fibres of orbicularis : pars lacrimalis
Lacrimal sac :
• In lacrimal fossa – anterior part of medial orbital
wall
• ( lacrimal bone and frontal process of maxilla )
• Enclosed by lacrimal fascia. Periorbita spits at
posterior lacrimal crest into two layers enclose sac
and meet at anterior lacrimal crest
15. • Between them alveolar tissue and venous plexus
Dimensions :
Length – 15mm
Breadth – 5 to 6 mm
Volume – 20cm
Parts :
Fundus (3-5cm)
Body (10-12 cm)
Neck
Relations :
• Medially – Anterior ethmoidal sinus in upper part
Middle meatus in lower part
• Anterolateral – Lacrimal fascia
16. • Lacrimal fibres of orbicularis ( Horner's muscle )
• Medial palpebral ligament only in upper part
• Angular vein crosses medial palpebral ligament
8mm from medial canthus
• Skin
Posteriorly :
• Lacrimal fascia
• Fibres of lacrimal part of orbicularis
• Septum orbitale
Nasolacrimal duct :
• Neck to inferior meatus of nose (30-40mm from
anterior nares)
17.
18. - 18mm length(12-24), 3mm diameter
- Upper end is narrowest
- Direction downwards , backwards and laterally
- Externally line joining ala to medial canthus
Intraosseous part intrameatal part
(12.5mm) (5.5mm)
- in nasolacrimal canal - mucous membrane of lat.
- Ridge in max.antrum wall of nose
- Lesions of max sinus
epiphora
- Lumen has many valves lowest end VALVE OF HASNER
- Prevents entry of air when blown through closed nose
19. - In fetus NLD is solid cord of cells canalized later
- 30% not canalized at lower end or delayed
congenital dacryocystitis
epiphora
Structure :
- Epithelium – 2 layers
- Sub epithelial tissue - lymphocytes
- Fibro elastic tissue – continuous with corium
- Plexus of vessels – engorgement causes epiphora
20. Blood supply :
• Superior and inferior palpebral A. – ophthalmic
A.
• Angular A.
• Infraorbital A.
• Nasal branches of Sphenopalatine A.
• Angular and infraorbital V. from above
• Nasal V. from below
Lymphatic drainage :
• Submandibular and deep cervical glands
21. Nerve supply :
• Sensory – Infratrochlear N.
Anterior superior alveolar N.
• Extirpation of lacrimal sac diminishes tears production may be reflex relation
22. Elimination of tears :
pre ocular tear film
lacus lacrimalis (inner canthus )
25% evaporation capillary action through
lacrimal pump mechanism
Lacrimal pump mechanism:
• pretarsal portion of orbicularis
• Preseptal portion( lacrimal fascia and Horner's muscle )
23. On eyelid closing :
Contraction of pretarsal fibres
compresses ampulla and shortens Canaliculi
tears in ampulla and hor. Canaliculi towards sac
Contraction of Preseptal fibres
opens the lacrimal sac
tears from Canaliculi into sac
- Inferior portion closes tightly prevents aspiration from nose
24. On eyelid opening :
Relaxation of pretarsal fibres
Canaliculi expand and reopen
Tears from lacus lacrimalis through Puncta
Relaxation of Preseptal fibres (Horner's muscle)
Collapse of sac Atony of sac
Tears into NLD Epiphora
25. From NLD to nose :
• Gravity
• Air current mechanisms
• Hasner valve – open when nose pressure low than NLD
