Anatomy of lacrimal apparatus
The lacrimal apparatus for each eye consists:
1. Secretory system
- i. Lacrimal gland and its ducts ii. Accessory lacrimal glands.
2. Excretory system
- i. Lacrimal puncta ii. Lacrimal canaliculi iii. Lacrimal sac iv. Nasolacrimal duct.
Lacrimal Glands
- Location: These are serous glands situated at the upper and outer angle of the orbit, in a depression known as the fossa for the lacrimal gland.
- Morphology: Each gland is approximately the size and shape of an almond. It is composed of secretory epithelial cells. Anteriorly the gland is divided into two parts—the upper orbital part and the lower palpebral part. Consist of 12 ducts which open into the fornix of the upper eye lid.
- Function: The glands secrete tears composed of water, salt and lysozyme, a bactericidal enzyme.
Accessory Lacrimal Glands
These are very small glands with the same structure as the lacrimal glands and they include:
- Glands of Krause: These are about 20 in the upper lid and about 8 in the lower lid situated within the stroma of the conjunctiva mainly near the fornix.
- Glands of Wolfring: These are few and situated near the upper border of tarsal plate.
Lacrimal Puncta: Two small openings situated superiorly and inferiorly on a small elevation called lacrimal papilla, about 6 mm from the inner canthus on each lid margin.
Lacrimal Canaliculi (cute word for small canals!) These are narrow tubular passages, located superiorly and inferiorly next to the lacrimal punca.
They are separated by a small body, the caruncle.