What is the cervix?

The cervix is the lower third of the uterus and opens into the vagina.  The opening into the vagina is called the external os.  . The internal os designated the end of the uterine cavity and the beginning of the cervix. The cervix contains a passage way from the uterine cavity to the vagina which is called the endocervical canal. At the end of the endocervical canal is the external os.  The appearance of the external os varies with a variety of factors including age, hormones and history of childbirth.

The cervix serves a number of functions.  The cervix allows the uterine lining to exit the body during the monthly menstrual period.  The cervical canal also allows sperm to travel from the vagina to the uterine cavity.  And during pregnancy the cervical os closes tightly and the endocervical canal fills with a mucous plug to keep the fetus in the uterus until birth.  In late pregnancy and during labor the cervix effaces and dilates to allow the passage of the fetus from the uterus to the vagina.

Kevin W. Windom, MD
OBGYN (Obstetrics & Gynecology)
The cervix is the lower part of the uterus, and this is the canal that attaches the uterus to the vagina.  One can think of the cervix as a passageway for blood from the uterus to be expelled out during a woman's period as well as this is the passageway for sperm to swim up through the vagina into the uterus and unite with an egg in the fallopian tube. 

The cervix is part of a woman's reproductive system. It's in the pelvis. The cervix is the lower, narrow part of the uterus (womb).

The cervix is a passageway:

The cervix connects the uterus to the vagina. During a menstrual period, blood flows from the uterus through the cervix into the vagina. The vagina leads to the outside of the body. The cervix makes mucus. During sex, mucus helps sperm move from the vagina through the cervix into the uterus. During pregnancy, the cervix is tightly closed to help keep the baby inside the uterus. During childbirth, the cervix opens to allow the baby to pass through the vagina.

This answer is based on source information from the National Cancer Institute.

Maria F. Daly, DO
Maria F. Daly, DO on behalf of MDLIVE
OBGYN (Obstetrics & Gynecology)
The cervix is the lower portion of the uterus.It is approximately one inch in length.Pap testing is performed on the cervix.
The cervix is in close proximity to the vagina and may be infected with such infections as Chlamydia or Gonorrhea.The cervix may  become infected with an acute or chronic cervicitis causing  inflammation as well as an abnormal discharge. This discharge may have an unpleasant odor and possibly an abnormal color such as yellow or bloody instead of a normally clear colored discharge.
The cervix is also the lower portion of the uterus where after unprotected intercourse and during a woman's fertile period sperm  ascend from the vagina through the cervix into the uterus to enter the Fallopian tubes to fertilize a woman's egg.
 Birth control pills change the mucous lining of the cervix to assist in preventing pregnancy.A cervical cap or a diaphram is placed over the cervix ,one of the methods of birth control to prevent pregnancy.
 During labor and delivery the cervix which is usually gently closed dilates to 10 centimeters to allow a baby to descend from the uterus through the cervix,into the vagina and out the birth canal to a new life.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.