lacrimal system ppt

lacrimal system anatomy
learn about lacrimal gland

1. LACRIMAL SYSTEM PRESENTED BY- Maaz ul haq C.L Gupta eye hospital

2. CONTENT Lacrimal glands Duct of lacrimal gland Histology of lacrimal gland Blood, nerve supply, lymphatic drainage& Venous Drainage Accessory lacrimal gland Lacrimal passage Lacrimal puncta Lacrimal canaliculi Lacrimal sac and its relation Nasolacrimal duct (NLD) 7. Blood, nerve supply, lymphatic drainage& venous drainage.

3. LACRIMAL APPARATUS It is concerned with the tear formation and transport. Lacrimal passage includes : Lacrimal gland Conjunctival sac Lacrimal puncta Lacrimal canaliculi Lacrimal sac Nasolacrimal duct

4. LACRIMAL GLAND Main lacrimal gland Located in anterolateral part of the roof of orbit in fossa for lacrimal gland. Divided into large superficial orbital part and small inferior palpebral part which are continuous with each other posteriorly.

5. ORBITAL PART Almond shaped Two surfaces (superior and inferior) two borders (anterior and posterior) two extremities (medial and lateral) Superior surface – convex and related to orbital part Inferior surface – concave and related to LPS

6. 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

7. PALPEBRAL PART 1/3 part 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.

8. LACRIMAL DUCTS 10-12 ducts pass downward and open in lateral parts of superior fornixs. 1-2 ducts also open in lateral part of the inferior fornixs. Since all the ducts pass through the palpebral part of the gland ,so the entire gland excision through it.

9. HISTOLOGY STRUCTURE OF THE 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 separated by septa. Acini has pyramidal cells which secrete the tears expelled by the contraction of myofibrils.

10. Stroma is formed by mesodermal tissue which contain connective tissue, elastic tissue, lymphoid tissue, plasma cells, rich nerve terminal and blood vessels.

11. BLOOD SUPPLY Main lacrimal gland supplied by lacrimal artery ,a branch of ophthalmic artery and transverse facial artery also supply the gland. Lacrimal veins draining the gland join the ophthalmic vein. Lymphatic drainage is along the Conjunctival drainage into the the preauricular lymph nodes.

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

13. ACCESSORY LACRIMAL GLANDS These includes: Glands of Krause Gland of wolfring Intraorbital gland Glands in the caruncle and plica semilunaris

14. Gland of Krause : Upper lid 40-42 Lower lid 6-8 Deeply situated in the conjunctiva near the fornix on lateral side. Gland of wolfring : Few in numbers Situated near the upper border of the tarsal plate. Rudimentary accessory lacrimal gland : Present in the caruncle, plica semilunaris and infraorbital region.

15. LACRIMAL PASSAGE Lacrimal puncta Two small or oval rounded openings one each eyelids. Upper puncta – 6mm in dia. Lower puncta – 6.5mm in dia. Lateral to inner canthus respectively. Each puncta is situated upon a slight elevation called lacrimal papilla, which becomes prominent in old age.

16. The puncta are surrounded by a ring of dense fibrous tissue which keeps them patent.

17. Lacrimal canaliculi- Hollow tubes of 0.5mm in dia. Connecting the puncta to the lacrimal sac. It has- Vertical part – 2mm in length Horizontal part - 8mm in length There is a dilation at the junction of these two parts – called AMPULLA.

18. The point of entry of common canaliculus into the lacrimal sac is called the lacrimal sinus of Maier. The canaliculi are lined by stratified squamous epithelium.

19. 3. Lacrimal sac- Dimension : 12-15mm in length 4-6mm anteroposteriorly 2-3 mm wide Situation : lies in lacrimal fossa formed by lacrimal bone and frontal process of the maxilla, bounded by ant. And post. Lacrimal crests and continues below with Nasolacrimal duct.

20. Parts – has 3 parts Fundus – portion above the opening of canaliculi (3-5mm). Body – middle part (10 -12mm) Neck – lower small part which is narrow and continues with the nasolacrimal duct.

21. RELATIONS OF LACRIMAL SAC Anteriorly to medial palpebral ligament Posteriorly to post. Lacrimal crest and orbicularis oculi Medially to middle meatus and ant. Ethmoidal sinus Laterally to skin, fascia and orbicularis oculi

22. 4. Nasolacrimal duct (NLD)- Continuation of lacrimal sac. It is divided into 2 parts- An interosseous part : 12.5mm An intermeatal part : 5.5mm The opening of nasolacrimal duct has a mucosal fold, the Valve of Hasner, which prevents air from entering the lacrimal sac on sudden blowing the nose.

23. STRUCTURE OF THE LACRIMAL SAC & NLD Double-layered epithelium The superficial layer composed of columnar cells, the deeper cells being flatter. Fibroelastic tissue of the lacrimal sac becomes continuous with that of the canaliculi.

24. BLOOD SUPPLY Superior and inferior br. Of ophthalmic artery , angular and infraorbital artery and nasal br. Of sphenopalatine artery. VENOUS DRAINAGE- Angular and infraorbital vessel above, below into the nasal vein.

25. LYMPHATIC DRAINAGE Submandibular and deep cervical nodes. NERVE SUPPLY Infratrochlear and anterior superior alveolar nerves.

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