The hymen is a thin membrane on the outside of the vagina, pinkish-white in color and 1-2 mm thick, with a pore in the middle called the hymenopore, which is the outlet for vaginal secretions and menstrual blood. The size and thickness of the hymen varies from person to person. The hymen protects the vagina from contaminants and infections. The hymen is a moist mucous membrane on both the front and back, with vascular tissue, nerve endings, and connective tissue between the two layers of mucous membrane. The shape of a woman’s hymen can be crescent-shaped, round, sieve-shaped, umbrella-shaped, etc. The size of the hole also varies greatly, from small ones that cannot even pass a finger to large ones that can accommodate two fingers, etc. The hymen may rupture and bleed after first intercourse or strenuous exercise, and there will be traces of hymen after performing normal childbirth.