Introitus

An introitus is an entrance that goes into a canal or hollow organ. The vaginal orifice is an introitus.

The vaginal introitus has also been used for classifying uterine prolapse:
 * 1st degree prolapse: cervix is in the vagina
 * 2nd degree: cervix at the level of the introitus
 * 3rd degree: cervix comes out of the introitus
 * procidentia: the uterus also comes out of the introitus