valve of Hasner

(redirected from Hasner's valve)

valve of Hasner 

A fold of mucous membrane at the lower end of the nasolacrimal duct. If well developed, it generally prevents air from being blown back from the nose into the lacrimal sac. Syn. plica lacrimalis; valve of Bianchi. See lacrimal apparatus.
References in periodicals archive ?
The ostium is usually protected by a fold of mucous membrane called Hasner's valve.
Care should be taken to avoid injury to the nasolacrimal duct and Hasner's valve.