How does the nasolacrimal duct connect the eyes and the nasal cavity?

The nasolacrimal duct is a tubelike structure that serves as a drainage pathway for tears, connecting the eye to the nasal cavity.12

The process begins as tears flow across the surface of the eye toward the inner corner of the eyelid. There, they enter two tiny openings known as puncta. These openings lead into small tubes called canaliculi, which carry the fluid into the lacrimal sac. The lacrimal sac acts as the dilated upper end of the nasolacrimal duct, which then directs the tears downward into the nasal cavity.312

This drainage system is essential for managing tear flow, particularly during periods of copious secretion. If the nasolacrimal duct becomes blocked, tears cannot properly drain into the nose, which can result in a watery eye and potential inflammation of the lacrimal sac.43