Nasolacrimal duct

Ductus nasolacrimalis

Sensory (eye & ear)OrgansHeadLeft and right

View left in 3D View right in 3D

What it is

A membranous canal running down from the lacrimal sac through a bony canal in the maxilla to open under the inferior nasal concha, guarded by a mucosal fold (valve of Hasner).

Function

Carries tears into the nose - which is why crying makes the nose run.

Size

12-18 mm long, 3-4 mm wide.

Clinical note

In ~5% of newborns the lower end is still closed, causing a watery, sticky eye that usually opens by itself within the first year.