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In order best to use and understand any book about gynecologic surgery, you really need first to be given a tour of your own anatomy. In all our years in practice, one of our most-used tools has been a book of color charts detailing a woman's insides. Let's look now at this anatomy-if you know it already, skip this chapter! Our bodies are made up of three cavities or spaces stacked one upon the other, rather similar to stacked storage bins. The top one is the thoracic cavity and contains the heart and lungs; the next is the abdominal cavity and contains the stomach, liver, spleen, and intestines. We are really not concerned with the upper body in this book (although, of course, they are vitally important to each of us); rather, we will focus on the bottom space-the pelvic cavity. A surgeon or anatomist might take issue with describing them this way, as the abdomen and the pelvis are not totally separate from each other, but it is simpler for us to picture them like this. We'll be looking at Figure 1.1, which is an illustration of the normal female pelvic anatomy. (It is interesting that in Asian medicine, the pelvis is the reservoir of the chi, or life force.)
The organs of most concern to your gynecologist-and, of course, to you, since they are yours-are the uterus, tubes, ovaries, vagina, vulva, bladder, and lower bowel. You can locate the uterus, tubes, ovaries, and vagina on Figure 1.1, and the bladder and bowel can be seen on Figure 1.2. The vulva is the fleshy lips you feel when you reach down and touch yourself. They enclose the opening of the vagina.
The normal, nonpregnant uterus is found low down in the pelvis. It is about ten centimeters (four inches) long and is shaped like an upside-down pear. In about 75 percent of women, the body or fundus of the uterus is tipped forward; this is what we mean when we say your uterus is anteverted. In the rest of us, the fundus is tipped backward; this is what is commonly referred to as a tipped or retroverted uterus. This is simply a variation on normal (for example, blue eyes versus brown eyes). Contrary to popular myth, a tipped uterus does not commonly prevent pregnancy. The cervix is the knobby neck of the "pear" and points down into the vagina. If you put your finger into your vagina, you will feel something a bit like the end of your nose: this is your cervix. When we do a Pap smear, we insert a speculum into your vagina and open it so that we can see your cervix. In the center of the cervix is a slit-like opening; it is from this opening that we take the samples for your Pap smear. This is also the opening through which your menstrual fluids flow.
Embracing your uterus on both sides are your Fallopian tubes. Each one is about ten centimeters or four inches long and looks rather like a sea anemone with a long tail; the fronds around the far end lie close to the ovary on each side. Or you could imagine them as arms curved around with fingers curling near the ovaries.
The ovaries are the two small oval organs that lie on either side of the uterus, embraced by the Fallopian tubes. Your ovaries have the important job of producing ova (eggs) and releasing one each month. They also produce those essential female sex hormones, which are responsible for your menstrual cycle and your feminine attributes.
The uterus is made up of overlapping bands of very thick muscle (the myometrium). This muscle is what allows the uterus to expand in pregnancy and to contract in labor. As you have no doubt noticed, this muscle is not under your voluntary control, unlike the muscles in your arms and legs. That is because it is a different type of muscle, called smooth muscle. The heart is also smooth muscle. This muscle is stimulated to contract by autonomic nerves (nerves not under your conscious control) and by hormones.
The lining of the uterus is called the endometrium. It is made up of two layers. The inner layer, which is adherent to the wall of the myometrium, is permanent; the more superficial layer is shed each month when you menstruate and is then built back up again. The endometrium is very sensitive to your hormones, and you can have abnormal bleeding from it at times other than your period (more about this in chapter 3).
All of these organs-your uterus, tubes, and ovaries-are covered by a clear, glistening membrane, rather like plastic wrap. This membrane, called the peritoneum, covers and protects the surfaces of all the organs in your abdomen and pelvis. A neat design, don't you think?
The bladder lies in front of the uterus, connected to the two kidneys by tubes, the ureters, which pass on each side of the cervix. The rectum lies behind the uterus. Above all these are the bowels. The vagina connects the uterus to the outside of your body and shares a common wall, in the front, with the bladder and urethra, and, in the back, with the rectum. Have a look at Figure 1.2. Obviously, conditions that affect one of these organs can affect the others, simply because of their close physical proximity. The uterus and bladder are held in their positions by a number of ligaments that act like struts to support them. These may be stretched during pregnancy and childbirth, or simply relax in later years, causing problems of prolapse, which we'll address later.
Your vagina connects your cervix and uterus with your vulva. The vulva is the outer part that consists of the labia or lips, large and small, and the clitoris. The clitoris is a very sensitive little nub of flesh toward the front of the slit area. It has very much to do with sexual responsiveness. In between the clitoris and the vagina is the opening of the urethra, or tube to the bladder. At the back of the vulva, between the vaginal opening and the anus, is the perineum. This is an area of skin and muscle that gets stretched and often torn during childbirth.
The external genitalia vary widely in size and shape and in amounts of pubic hair, from one woman to another. After all, your mouth isn't exactly like your friend Gail's, is it? We're all pretty much normal and the variations keep life interesting.