Introduction to normal uterus

We all know that the uterus is an important organ in our female body, and it is also one of the important organs in the female reproductive system. From the embryo and female fetus to the old woman, the cervix involves the disease prevention and treatment and health care issues such as gynecology, obstetrics, family planning, women's health and reproductive health throughout a woman's life. It involves women's own health, family happiness, economic and social issues, and is also closely related to sex and reproduction. So what kind of uterus is a normal uterus? Let me introduce it to you below.

The cervix is ​​located in the lower part of the uterus. It is approximately cone-shaped, 2.5 to 3 cm long, with the upper end connected to the uterine body and the lower end extending deep into the vagina. In layman's terms, as the name suggests, it means the cervix of the uterus, which connects the vagina and the uterus. The specific location is a little further inside the vagina. Use your middle finger to push it as far as you can, and it is almost there.

The position of the external cervical os in the vagina determines the type of uterine displacement. Generally, the normal position of the uterus in an adult woman is slightly anteverted and flexed. "Inclination" refers to the angle between the long axis of the uterine body and the long axis of the vagina; "flexion" refers to the angle between the long axis of the uterine body and the long axis of the cervix. Normal anteversion means that the uterine body and the vagina form an inclination angle that is open forward and approximately right angles; normal anteflexion means that the uterine body and the cervix form a flexion angle of about 170° that is open forward. The external os and lips of the cervix are in contact with the posterior wall of the vagina. Various physiological or pathological factors may lead to changes in the angle of uterine "tip" and "flexion", resulting in different types of uterine displacement: anterior displacement (anteversion, anteflexion, anteversion-anteflexion), posterior displacement (retroversion, retroflexion, retroversion-retroflexion and horizontal position) and lateral displacement (lateral tilt, lateral flexion, lateral tilt and lateral flexion), etc.

The vault at the top of the vagina divides the cervix into two parts: the part of the cervix that protrudes into the vagina is called the cervicovaginal part, and the part above the vaginal vault is called the upper cervicovaginal part. The center of the cervix is ​​a long, fusiform lumen that is slightly flattened front to back. Its upper end is connected to the uterine cavity through the internal cervical os, and its lower end opens to the vagina through the external cervical os. The cervical canal is between the internal and external openings. The external cervical os is round in nulliparous women and transversely fissured in women who have given birth through vaginal delivery.

The size of the cervix and the ratio of the uterine body vary with age and endocrine status. The cervical wall is composed of the mucosa, muscularis and adventitia.

1. The cervical canal mucosa is the endocervix, which is covered by a single layer of columnar epithelium that secretes mucus. The epithelium sinks into adenoid crypts in the lamina propria, which are commonly called cervical glands. They can secrete mucus, which is the main component of leucorrhea.

2. There are reserve cells on the surface of the endocervical canal and below the glandular columnar epithelium and above the basement membrane, which have the potential for bidirectional differentiation: proliferation and differentiation into columnar epithelial cells and metaplasia into squamous epithelium;

3. The area from the external cervical opening to the vaginal vault is covered with stratified squamous epithelium;

4. The junction area between the columnar epithelium of the cervical canal and the vaginal squamous epithelium outside the cervix is ​​called the cervical epithelial transition zone or transformation zone. The position of the junction area between the two types of cells is not fixed and may move with the level of estrogen in the female body, age, endocrine system, vaginal pH and pathological condition. If the estrogen level is high, such as in women of childbearing age, the transition zone moves outward toward the external cervical os, exposing the columnar epithelium in the endocervical canal. The blood supply of the cervix mainly comes from the uterine artery, which reaches the outside of the uterus through the parauterine tissue, crosses the ureter to the side edge of the uterus about 2 cm above the level of the internal os of the cervix, and then divides into upper and lower branches. The lower branch is distributed in the cervix and upper vagina, called the cervicovaginal branch, and the vein runs along with it. The nerves of the cervix mainly come from the presacral plexus, most of which form the pelvic plexus next to the cervix and are distributed in the uterine body, cervix, etc.

The uterus is very important for all female friends, so many of our female friends must take good care of their uterus. And now do you understand what the editor has introduced above about what a normal uterus is? Be sure to read this article written by the editor carefully.