The cervix is located in the lower part of the uterus and is one of the female internal reproductive organs. The upper end of the cervix is connected to the body of the uterus through the internal cervical opening and the lower end penetrates into the vagina through the external cervical opening. The size of the cervix is related to the age of the woman. In infancy, the body of the uterus is one-half the size of the cervix; in adult women, the body of the uterus is twice the size of the cervix; in old age, the uterus atrophies and the body of the uterus is about the same size as the cervix. For example, during ovulation, the cervical mucus is egg-white like, thin and long drawn, which is conducive to the passage of sperm, so if intercourse is conducive to pregnancy, it is recommended to take contraceptive measures if you do not want to get pregnant. This is commonly known as the safe period and the risk period. The cervix is an important channel for menstrual discharge and delivery of the fetus. A vaginal speculum can be used during routine gynecological examinations to clearly see the nature of the cervix, the presence of erosions, cysts and polyps, etc. Adult women who have sex, especially those over 30 years old, are recommended to undergo annual cervical cancer screening to detect cervical lesions in advance. In conclusion, the cervix is one of the internal reproductive organs of women, located inside the vagina, at the lower end of the uterine body.