The uterus is a unique organ for women and is the cradle for the next generation, yet it is a very fragile organ that is often bothered by various diseases. The cervix is part of the uterus and can cause a variety of gynecological diseases, including inflammation, verrucous lesions, low and high risk HPV infections (condyloma acuminata, cervical cancer), benign tumors, malignant tumors, etc. We also know that there are many medical tests for the cervix, such as TCT (liquid-based thin layer cell test), pap smear, HPV-HC2 test, colposcopy, etc. Knowing and understanding the cervix also helps us to better interpret these tests. Today, let’s get to know the cervix. Structure of the uterus] The uterus is located in the middle of the pelvis, between the bladder and the rectum. The uterus can be divided into four parts: the base, the body, the isthmus and the neck. The bottom of the uterus lies above the bladder and is the part of the uterus above the mouth of the fallopian tubes on both sides; the narrow columnar part at the bottom is the cervix; the part between the bottom and the cervix, the more open part becomes the body of the uterus, and the narrow part is the isthmus, which gradually expands with pregnancy and is the location of the fetus taken by caesarean section. The upper part of the uterus on both sides of the edge meets the fallopian tube, called the uterine horn. The front of the uterus is adjacent to the top of the bladder, the front of the upper part of the vagina of the cervix is adjacent to the bottom of the bladder, the vaginal part of the cervix is adjacent to the urethra through the urethro-vaginal septum; the back of the uterus is adjacent to the rectum through the recto-uterine sink and the recto-vaginal septum. Therefore, if the uterus is inflamed or the cervix is inflamed, it will constantly irritate the bladder and the person will have the urge to pass stool and frequent urination. This is also the medical theory that I often talk to patients in the clinic about frequent urination when there is a prolonged high-risk HPV infection with other gynecological problems. Also, if the germs infect the urethra, they can easily cause cross infection in the vagina. Vaginal germs can also cause anal germs. That is, cross-infection of the urethra, vagina and anus. The cervix is located in the lower part of the uterus and can be divided into two parts: the upper part is connected to the uterine body and is called the upper cervicovaginal part; the lower part is deep in the vagina and is called the cervicovaginal part or ectocervix. The cervix is relatively fragile and inflammation and cancer tend to occur in the cervix. The tube surrounding the cervix, the cervical canal, opens at the upper end of the uterus, called the endocervical opening, and at the lower end of the vagina, called the ectocervix. The wall of the cervix is composed of mucosa, myometrium and ectocervix: the mucosa of the cervical canal, the endocervix, is composed of a layer of mucus-secreting columnar epithelium with cervical glands that secrete mucus and become the main component of the leucorrhoea. The ectocervix is mostly covered by non-keratinized squamous epithelium. The area where the squamous and columnar epithelium meet is called the squamocolumnar junction, and its position is not static, moving with estrogen levels, age, endocrine, etc. What we often refer to as cervical erosion is the outward movement of the squamous junction, where the columnar epithelial cells are turned out, a normal physiological phenomenon. About cervical erosion, it will be described in detail in my subsequent articles. The role of the cervix] (1) secrete mucus to facilitate the passage of sperm, while playing a protective role. The cervix secretes mucus, the amount and consistency of which changes periodically. During ovulation, the mucus cells facilitate the passage of sperm and at the same time provide energy for the sperm. After ovulation, the mucus is less and more viscous and forms a mucus plug in the cervical canal, which plays a protective role. (2) The cervical canal can store sperm. The inner wall of the cervical canal has many cryptic fossae and fissures, which allow sperm to be stored temporarily for 1 to 2 weeks, and then enter the uterus when the sperm have gained energy. (3) Protect the gate and secretion channel of the fetus. The fetus grows gradually during pregnancy, but the uterus remains closed and plays a protective role. However, by the time of delivery, the opening of the cervix grows and opens the door for smooth delivery of the fetus.