Nasolacrimal duct
Ductus nasolacrimalis
Definition
The nasolacrimal duct is the continuation of the lacrimal sac that drains tears from the lacrimal sac into the nasal cavity. It extends inferiorly from the lacrimal sac through the bony nasolacrimal canal within the maxilla and opens into the inferior meatus of the nose beneath the inferior nasal concha.
The nasolacrimal duct is lined by mucous membrane (with columnar epithelium) and is partly surrounded by a venous plexus. At its distal end, a mucosal fold called the lacrimal fold or the valve of Hasner helps prevent reflux of air or nasal contents into the duct.
Obstruction of the nasolacrimal duct may cause epiphora and predispose to dacryocystitis.
References
Cochran ML, Aslam S, Czyz CN. Anatomy, Head and Neck: Eye Nasolacrimal. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482213/
Standring, S. (Ed.). (2015). Eye (Chapter 42). In Gray's anatomy: The anatomical basis of clinical practice (41st ed., pp. ). Churchill Livingstone.
Medscape (n.d.) Lacrimal system anatomy. Available at: Medscape (Accessed: 13 May 2026).
