Lacrimal canaliculus

The lacrimal canaliculus is a small epithelial-lined channel that carries tears from the lacrimal punctum to the lacrimal sac. There are two canaliculi:

• The superior lacrimal canaliculus, and

• The inferior lacrimal canaliculus

Location and Course

Each canaliculus begins at a lacrimal punctum and has:

1. Vertical part

• Approximately 2 mm long and extends vertically from the punctum.

2. Horizontal part

• Approximately 8 mm long and it runs medially toward the lacrimal sac.

The superior and inferior canaliculi usually unite to form a common canaliculus before opening into the lacrimal sac.

Structure

• Each lacrimal canaliculus is lined by stratified squamous epithelium, surrounded by elastic tissue

• Closely associated with fibres of the orbicularis oculi muscle (lacrimal part), aiding tear drainage during blinking

Function

• Conduct tears from the lacrimal puncta to the lacrimal sac, contributing to the lacrimal pump mechanism.