LACRIMAL APPARATUS.pptx
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The lacrimal apparatus includes structures involved in tear secretion and drainage. It consists of the lacrimal gland, conjunctival sac, lacrimal puncta and canaliculi, lacrimal sac, and nasolacrimal duct. Tears are produced by the lacrimal gland and drained through the puncta, canaliculi, lacrimal sac, and nasolacrimal duct into the nose. Inflammation of the lacrimal sac is called dacryocystitis and excessive tearing is called epiphora.
LACRIMAL APPARATUS.pptx
- 1. LACRIMAL APPARATUS Dr. Mohammad Amaan
- 2. Lacrimal Apparatus The structures concerned with SECRETION and DRAINAGE of the lacrimal /tear fluid forms the lacrimal apparatus.
- 3. • The lacrimal apparatus include structures concerned with:- • Formation of tears - Lacrimal gland • Drainage of tears - Lacrimal passage The lacrimal passage include:- Punctum, canaliculi, lacrimal sac and Nasolacrimal duct
- 4. It is made up of the following parts:- 1. Lacrimal gland and its ducts 2. Conjunctival sac 3. Lacrimal puncta and lacrimal canaliculi 4. Lacrimal sac 5. Nasolacrimal duct
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- 6. 1. Lacrimal gland and its ducts • Main lacrimal gland • Small accessory lacrimal glands :- - gland of Krause - gland of Wolfring
- 7. Main lacrimal gland • It is a serous gland • Situated :- - mainly in the lacrimal fossa (on the anterolateral part of the roof of the orbit) - partly on the upper eyelid • It is ‘J’ shaped • It lies on the tendon of levator palpebrae superioris (LPS)
- 8. • It has:- a) A large upper ORBITAL PART (large and deep) b) A smaller lower PALPEBRAL PART (small and superficial, lying within the eyelid) Ducts: 10-12 ducts open into the superior fornix • Most of the ducts of the orbital part pass through the palpebral part • Removal of the palpebral part is functionally equivalent to removal of the entire gland.
- 9. . Blood supply – lacrimal artery, a branch of ophthalmicartery Nerve supply – lacrimal nerve, a branch of ophthalmic division of fifth cranial nerve • The nerve has both sensory and secretomotor fibres • The lacrimal fluid is secreted by the lacrimal gland flows into the conjunctival sac. Periodic blinking helps to spread the fluid over the eye. • Most of the fluid evaporates, the rest is drained by the canaliculi and when excessive , it overflows as tears.
- 10. Accessory lacrimal glands • Located in the middle of lid (Wolfring glands) or superior & inferior fornices (Krause glands).
- 11. 2. Conjunctival sac The conjunctival lining the deep surfaces of the eyelid Palpebral conjunctiva. (Thick and opaque) The conjunctival lining the front of the eyeball Bulbar conjunctiva (Thin and transparent)
- 12. 3. Lacrimal Punctum and lacrimal canaliculi • On medial side there are 2 lacrimal Punctum - upper Punctum and - lower Punctum • Each Punctum lies on a elevation called - lacrimal papilla
- 13. . CANALICULI • Begins from the lacrimal Punctum • 10 mm long • Consist of :- i. vertical part – 2 mm long & ii. horizontal part – 8 mm long
- 14. • Both the upper and the lower canaliculi joins to form a COMMON Canaliculi, and opens in the Lateral wall of the LACRYMAL SAC. • The common canaliculi drains the lacrimal into the lacrimal sac • And at the junction of the common canaliculi and lacrimal sac there is a fold of mucosa called as VALVE of ROSENMULLER, which prevents the back flow entry of the tears.
- 15. 4. Lacrimal sac • It is a membranous sac, lies in the lacrimal fossa behind the medial palpebral ligament which is:- - 12 mm long and - 5 mm wide • Formed by:- i) Lacrimal bone & ii) frontal process of maxilla • Common canaliculi drains lacrimal into the lacrimal sac • Is consist of :- i. Fundus ii. Body and iii. Neck
- 16. 5. NASOLACRIMAL DUCT • Neck of the lacrimal sac continues into the NASOLACRIMAL DUCT / lower end of the lacrimal sac continues into duct. • It runs downwards, backwards and laterally, and opens into the INFERIOR MEATUS OF THE NOSE. • At the end the Nasolacrimal duct there is a fold of mucous membrane which forms a valve called as – VALVE OF HASNER.
- 17. Clinical Anatomy • Inflammation of lacrimal sac is called DACRO – CYSTITIS. • Excessive secretion of the lacrimal fluid over flowing on the cheeks is called EPIPHORA