View source for Nasolacrimal duct

{{Infobox Anatomy |
  Name         = Nasolacrimal duct |
  Latin        = d. nasolacrimalis |
  GraySubject  = 227 |
  GrayPage     = 1029 |
  Image        = Gray896.png |
  Caption      = The lacrimal apparatus. Right side. |
  Image2       = Gray1199.png |
  Caption2     = Outline of bones of face, showing position of air sinuses. |
  System       = |
  MeshName     = Nasolacrimal+Duct |
  MeshNumber   = A09.371.463.640 |
  DorlandsPre  = d_29 |
  DorlandsSuf  = 12314970 |
}}
The '''nasolacrimal duct''' (sometimes called '''tear duct''') carries [[tears]] from the [[lacrimal sac]] into the [[nasal cavity]]. Excess tears flow through nasolacrimal duct which drains into the [[inferior nasal meatus]]. This is the reason the nose starts to run when a person is crying or has watery eyes from an allergy, and why one can sometimes taste eye drops.

Like the lacrimal sac, the duct is lined by [[stratified columnar epithelium]] containing mucus-secreting [[goblet cells]], and is surrounded by connective tissue. 

Obstruction of the nasolacrimal duct leads to the excess overflow of tears called ''[[epiphora (medical)|epiphora]]''. A congenital obstruction can cause cystic expansion of the duct and is called a [[dacrocystocele]] or Timo cyst. Persons with dry eye conditions can be fitted with [[punctal plugs]] that seal the ducts to limit the amount of fluid drainage and retain moisture.

The canal containing the nasolacrimal duct is called the [[nasolacrimal canal]].

==Additional images==
<gallery>
 Image:Gray196.png|Roof, floor, and lateral wall of left nasal cavity.
</gallery>

<br>

==See also==
*[[Congenital lacrimal duct obstruction]]
*[http://rad.usuhs.mil/medpix/index.html?mode=single&recnum=8298* Dacrocystocele]
*[[Lacrimal apparatus]]

==External links==
* {{SUNYAnatomyFigs|33|04|09}}
* {{NormanAnatomy|lesson9}}

{{Accessory organs of the eye}}

{{DEFAULTSORT:Nasolacrimal Duct}}
[[Category:Ophthalmology]]
[[Category:Anatomy]]

[[de:Tränenwege]]
[[es:Conducto nasolagrimal]]
[[fr:Canal lacrymonasal]]
[[pl:Przewód nosowo-łzowy]]
[[fi:Kyynelkanava]]
[[zh:泪器]]
[[Category:2Fix]]