An inconstant fold or valve of mucous membrane sometimes found in the root or upper wall of the navicular fossa of the urethra. [ MP:anna MP:0011839 http://www.drugs.com/dict/valve-of-navicular-fossa.html ]
Synonyms: urethral valve of Guérin Guérin's fold Guérin's valvule Guerin's valve valvula fossae navicularis valve of fossa navicularis of urethra