Know Your Body - An Overview of Pelvic Anatomy

If you have pelvic pain, knowledge of the pelvic organs and their functions can be important as you seek treatment and solutions. This knowledge can help you communicate with medical professionals. By using anatomical terms to describe your symptoms, you can give your health care provider a head start in the diagnosis process. Body knowledge can also help you understand what the health care provider is saying and evaluate any recommendations. This section will provide basic information about the pelvic organs and related structures. Also remember to ask your physician or other health care professional questions if you do not understand a term or phrase or if you have other questions about your body.

The Pelvic Cavity

Uterus

The uterus is a pear-shaped muscular organ primarily designed for childbearing. A baby is carried and nourished in the uterus as it grows from a tiny collection of cells to a full-term fetus ready to emerge into the world as a healthy newborn. In its non-pregnant state, a typical uterus is approximately 2 1/2 to 3 1/2 in. long and 1 1/2 in. at its widest point. To accommodate a growing baby, the uterus is capable of enormous expansion. During pregnancy, its weight increases from about 3 ounces to 2.2 pounds and its capacity increases more than 4000 times.

The uterus is suspended in the pelvic cavity by the round ligaments, though its position varies from woman to woman. In most women, the uterus faces forward and rests on top of the bladder when a woman is standing. However, in about 20% of women, the uterus faces backwards. A uterus in this position is also referred to as a retroverted uterus, tilted uterus or tipped uterus. Most women with a tipped uterus don't experience any symptoms. But in some women a tipped uterus causes problems including pain during intercourse or during their periods.

Endometrium

The inner lining of the uterus is called the endometrium. Each month, this layer thickens under the influence of the hormones estrogen and progesterone in preparation for pregnancy. If pregnancy occurs, the endometrium nourishes the fetus during the first few weeks of life. If pregnancy does not occur, the endometrium is shed as your menstrual period. The function of the endometrium is of particular interest to women suffering from endometriosis. The symptoms of endometriosis are caused when endometrial tissue is found outside of its normal location inside of the uterus. As this displaced endometrial tissue grows and bleeds each month in response to female hormones, affected women may experience pain, scarring and other complications.

Cervix

The cervix is the entrance to the uterus. During menstruation, blood and tissue flow out of the uterus through the cervix. The cervix is also the entryway to the uterus for sperm. During childbirth, the cervix dilates allowing for delivery of the baby.

Some physicians believe that in women with a tipped uterus, the cervix may be displaced so that fertility is affected.

Ovaries

The ovaries contain all of the eggs a women will ever have. The eggs are lodged in microscopic bubbles called follicles. These follicles produce a number of different reproductive hormones including estrogen, progesterone, and androgens.

Fallopian tubes

The fallopian tubes are positioned between the ovaries and the uterus. Conception takes place in a tube, after which the fertilized egg travels down the narrow tubal passageway toward the uterus. The egg then implants itself in the uterus where it continues to grow during the nine months of pregnancy.

Vagina

The vagina is the muscular canal lined with mucous membranes that extends from the outside of the body to the cervix of the uterus. The vagina serves as the conduit for the discharge of menstrual flow and is the passageway through which the fetus is delivered.

Vulva

The vulva is the external part of a woman's genitals and includes the folds of skin called the labia, the clitoris and the opening to the vagina.

Cul-de-Sac

The uterosacral ligaments which help support the uterus in the pelvic cavity, the cervix, the top of the vagina and the rectum are all located near an area of the pelvis called the cul-de-sac. Endometriosis is frequently found in the cul-de-sac. Women with endometriosis in this area can experience symptoms such as painful intercourse (dyspareunia), pain with bowel movements, leg pain and low back pain.