QS Study

Lacrimal Apparatus

The structures concerned with secretion and drainage of the lacrimal fluid (tear fluid) constitute the lacrimal apparatus. It is the system responsible for the drainage of lacrimal fluid from the orbit. Lacrimal fluid acts to the clean, nourish and lubricate the eyes. It forms tears when produced in excess.

Components of lacrimal apparatus –

(1) Lacrimal gland: It is a serous gland. It secretes the tears, and its excretory ducts, which convey the fluid to the surface of the human eye;

  • Situation: Chiefly in the lacrimal fossa and partly on the upper eyelid.
  • Parts: Orbital part and Palpebral part.

(2) Lacrimal ducts: About a dozen lacrimal ducts open into the conjunctival sac near the superior fornix.

(3) Conjunctival sac: The potential space between palpebral & bulbar conjunctiva is the conjunctival sac.

(4) Lacrimal puncta & lacrimal canaliculi: Each lacrimal canaliculus begins at the lacrimal punctum and opens into the lacrimal sac. It has a dilated ampulla at the bend. It is 10 mm long.

Parts: Vertical part and Horizontal part.

Lacrimal Apparatus 1

Fig: Lacrimal Apparatus

(5) Lacrimal sac: It is a membranous sac situated in the lacrimal groove.

  • Size: 12mm long, 5mm wide.
  • Upper end: Blind.
  • Lower end: Continuous with the nasolacrimal duct.

(6) Nasolacrimal duct: It is a membranous passage.

  • Size: 18mm long.
  • Begins: at the lower end of the lacrimal sac.
  • Opens: Into the inferior meatus of the nose.
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