Sense organs (eye and ear)
Nasolacrimal duct
Ductus nasolacrimalis
- Origin
- Runs from the lacrimal sac down through the nasolacrimal canal of the maxilla
- Insertion
- Opens below the inferior nasal concha into the inferior nasal meatus, closed by the valve of Hasner
- Function
- Drains tear fluid into the nasal cavity, which is why the nose runs when crying and the eye waters with a cold
- Innervation
- Sensory via the infraorbital nerve (V2)
- Movement & chain
- The valve of Hasner acts as a non-return valve during blowing and sneezing
- Palpation
- Patency tested with fluorescein (disappearance test) or by syringing the lacrimal passages
- Clinical
- Congenital obstruction from an unopened valve of Hasner (watering eye in infants), acquired stenosis, dacryocystorhinostomy as treatment
- Segmental innervation
- Sensory V2
- In clinical practice
- Eye drops can be absorbed systemically along this route: punctal compression after instillation limits side effects
- Region in the model
- Sense organs (eye and ear)