- What is the uterine cervix?
- How is the cervix structured: exocervix and endocervix
- How is the cervix structured: endocervical canal and squamocolumnar junction
What is the uterine cervix?
The uterine cervix or neck of the uterus is the lower portion of the uterus, which represents the junction between vagina and uterus. The uterine cervix, that can undergo important morpho-functional changes, is where spermatozoids pass (and become active) for fertilization but is also where the menstrual flow and the foetus during delivery go through. The tissue that forms the cervix is constituted by the myometrium. The uterine cervix has a cylindrical-conical shape and a length between 2.5 and 4 cm with a diameter of about 2.5 cm. Its morphology is variable depending on the woman’s age and on the number of children she has had. The uterine cervix is also where on of the most common and feared female cancers is developed: cervical cancer.
How is the cervix structured: exocervix and endocervix
The cervix is divided into two areas:
- A portion above the vagina or endocervix, which is connected above with the isthmus and the body of the uterus and below with the exocervix.
- A vaginal portion, also called exocervix, which is connected above with the endocervix and below with the vaginal mucosa. Such anatomical structure does not have any glands and can be observed during a gynaeocological examination following dilatation of the vagina.
How is the cervix structured: endocervical canal and squamocolumnar junction
The canal that connects the external orifice of the uterus to the internal one is called endocervical canal. Inside the cervical canal there are infoldings that define cervical crypts that collect mucus. Cervical crypts become part of the tissue forming a network of branched tabular glands that secrete mucus, whose physical-chemical characteristics change according to the phase of the cycle.
The cervical canal has a mucosa that is different from the endometrium in terms of function and structure. In the neck of the uterus, the endometrium is not as smooth as in the overlying areas but instead has infoldings that constitute the arbor vitae. The area between the epithelium in the endocervical portion and the epithelium in the exocervical portion is known as squamocolumnar junction. In young women, this junction is located in the vaginal area of the cervix, while in older women such junction moves into the cervical canal. This transition area is very important in oncology because it is the anatomical area where cervical cancer mainly develops.