The anterior wall of the female vagina is about 7 to 9 centimeters deep and the posterior wall of the vagina is about 9 to 12 centimeters deep. There are also individual differences in the depth of the female vagina. The vagina is the connecting part of a woman’s internal and external reproductive organs, and is wider at the cervical area, forming a channel that is wider at the top and narrower at the bottom. The vagina is the organ through which a woman’s menstrual flow occurs, the fetus is delivered from the vagina, and sexual intercourse takes place. The front and back walls of the vagina are composed of vaginal mucosal tissue, muscular tissue and other components of the muscular tube, with a certain degree of elasticity and stretch, the vaginal tissue surface has many transverse folds, under normal circumstances can accommodate two fingers . When the vagina is in a state of excitement, the depth and width of the vagina will be increased to varying degrees, and can pass through the biparietal diameter of about 10 centimeters fetal head. As the vagina is directly connected to the outside world and the cervical area, it is susceptible to invasion by pathogens and induces various vaginitis, which manifests itself in symptoms such as vulvar itching and increased secretions.