Lacrimal Apparatus: Anatomy, Physiology, Pathology, Watering

Lacrimal Apparatus is the system which helps the secretion of tear fluid and its drainage. Here is the complete discussion of lacrimal apparatus i.e: Applied Anatomy, Applied Physiology, Drainage of tear, Watering, Pre-corneal tear film and Disease of Lacrimal gland and sac.

LACRIMAL APPARATUS

APPLIED ANATOMY:

A) Secretory Portion:

i)Lacrimal Gland

ii) Accessory Lacrimal Glands [Glands of Krause & Glands of Wolfring]

B) Drainage Portion:

i) Puncta: Superior & Inferior

ii) Canaliculi: Superior, Inferior, Common

iii) Lacrimal Sac

iv) Nasolacrimal Duct

APPLIED PHYSIOLOGY:

The tear is secreted from Lacrimal and Accessory Lacrimal Glands:

i) Evaporation

ii) Drain

iii) Form Aqueous Humour

DRAINAGE OF TEAR:  

Tear > Conjunctival Sac > Puncta > Inferior Canaliculi > Common Canaliculi > Lacrimal Sac > Nasolacrimal Duct > Inferior Meatus of Nose.

WATERING:

It is the overflow of tear fluid.

a) Lacrimation: Due to lacrimal hypersecretion.

b) Epiphora: Due to lacrimal drainage problem:

i) Obstruction

ii) Malposition due to Ectropion or Entropion

iii) Lacrimal Pump Failure

PRE-CORNEAL TEAR FILM:

Consists of [Outside to Inwards]

a) Lipid bilayer: Outer layer, secreted by the Meibomian glands.

b) Aqueous layer: Middle Layer, secreted by the Lacrimal gland.

c) Mucin layer: Inner layer, secreted by the Goblet cells of the conjunctiva.

DISEASES OF LACRIMAL GLAND:

a) Dacryoadenitis: Inflammation of lacrimal gland.

b) Tumor: Pleomorphic adenocarcinoma, Benign Mixed Tumour

DISEASES OF THE LACRIMAL SAC:

a) Dacryocystitis: Inflammation of lacrimal sac.

Types: i) Infantile dacryocystitis

ii) Adult dacryocystitis: Acute, Chronic