The cervix is the neck of the womb and connects the vagina and uterus.
The cervix is made of cartilage covered by smooth, moist tissue, and is about 2.5cm across. There are two main portions of the cervix:
The part of the cervix that can be seen from inside the vagina during a gynaecological examination is known as the ectocervix. An opening in the centre of the ectocervix, known as the external os, opens to allow passage between the uterus and vagina.
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The endocervix, or endocervical canal, is a tunnel through the cervix, from the external os into the uterus.
The overlapping border between the endocervix and ectocervix is called the transformation zone.
The cervix produces cervical mucus that changes in consistency during the menstrual cycle to help prevent or promote pregnancy.
During childbirth, the cervix dilates widely to allow the baby to pass through. During menstruation, the cervix opens a small amount to permit passage of menstrual flow.
- Cervical cancer: Most cervical cancer is caused by infection by the human papillomavirus (HPV). Regular smear tests can help prevent cervical cancer in most women.
- Cervical incompetence: Early opening, or dilation, of the cervix during pregnancy that can lead to premature delivery. Previous procedures on the cervix are often responsible.
- Cervicitis: Inflammation of the cervix, usually caused by infection. Chlamydia, gonorrhoea, and herpes are some of the sexually transmitted infections that can cause cervicitis.
- Cervical dysplasia: Abnormal cells in the cervix that can become cervical cancer. Cervical dysplasia is frequently discovered after a smear test.
- Cervical intraepithelial neoplasia (CIN): Another name for cervical dysplasia.
- Cervix polyps: Small growths on the part of the cervix where it connects to the vagina. Polyps are painless and usually harmless, but they can cause vaginal bleeding.
- Pelvic inflammatory disease (PID): Infection of the cervix, known as cervicitis, may spread into the uterus and fallopian tubes. Pelvic inflammatory disease can damage a woman's reproductive organs and make it more difficult for her to become pregnant.
- Human papillomavirus (HPV) infection: Human papillomaviruses are a group of viruses, including certain types that cause cervical cancer. Less dangerous types of the virus cause genital and cervical warts.