Sexual Anatomy, Reproduction, and the Menstrual Cycle
Sexual Anatomy: The Self-Guided Tour
A rosebud or a smile?
If you’re taking the tour, now slide your middle finger as far back into your vagina as you can. Notice that your finger goes in at an angle, not straight up the middle of your body. With your finger you may be able to just feel the end of your vagina. This part of the vagina is called the fornix. (If you are having trouble reaching it, bring your knees and chest closer together so your finger can slide in farther. However, some women still may not be able to reach.) A little before the end of the vagina you can feel your cervix, the part of the uterus that rests in the back of the vagina and is the door to the uterus. The tip of the cervix is the os, the opening to the uterus. Women who have never had a vaginal birth have an os that feels like a rosebud. Women who have given birth vaginally have an os that, when you run your finger along it, feels like a smile. The entrance into the uterus through the cervix is about the diameter of a very thin straw. It is closed with mucus. No tampon, finger, or penis can go up through it (this is why you never need to worry that anything can get “lost” inside your vagina). The os is capable of expanding enormously during labor and delivery to allow a baby to fit through.
The cervix is the base of the uterus, or womb. It is sensitive to pressure but has no nerve endings on its surface. The uterus changes position, color, and shape during the menstrual cycle and during sexual excitement as well as during puberty and menopause. Thus, the place where you feel the cervix one day may be slightly different from where you feel it the next. Some days you can barely reach it.
Find your orgasm, here!
Now you see it…
The clitoris is a unique and complex organ. It is special in that its only function is sexual arousal (this is unique to women!). If you remember nothing else about it, remember that it is the primary location for sexual arousal—the details are important, too, but that’s the big picture.
Once again, find the vestibule (gently spread back your inner lips), and look more closely at it. Starting from the top, right below the mons area you will see the inner lips joining to form a soft fold of skin, or hood, over and connecting to the glans, or tip of the clitoris. Gently pull the hood up to see the glans. This is the most sensitive spot in the entire genital area. It is made up of erectile tissue that swells during sexual arousal. (If you are taking the tour, now let the hood slide back over the glans.)
…Now you don’t—Felt but not seen…
Extending from the hood up to the pubis symphysis (the joint), you can now feel a hardish, rubbery, movable cord right under the skin. It is sometimes sexually arousing if touched. This is the shaft of the clitoris. It is connected to the bone by a suspensory ligament. You cannot feel this ligament or the next few organs described, but they are all important in sexual arousal and orgasm.
At the point where you no longer feel the shaft of the clitoris, it divides into two parts, spreading out like a wishbone but at a much wider angle, to form the crura or legs (singular: crus), the erectile tissue that attaches to the pelvic bones. The crura of the clitoris are about three inches long. Starting from where the shaft and crura meet, and continuing down along the sides of the vestibule, are two bundles of erectile tissue called the bulbs of the vestibule. These, along with the whole clitoris and an extensive system of connecting veins and muscles throughout the pelvis, become firm and filled with blood during sexual arousal. This process is called pelvic congestion. Some pelvic congestion can occur during the menstrual cycle right before your period comes. Both the crura of the clitoris and the bulbs of the vestibule are wrapped in muscle tissue. This muscle helps to create tension and fullness during arousal and contracts during orgasm, playing an important role in the involuntary spasms felt at that time.
The vestibular, vulvovaginal, or Bartholin's glands are two small rounded bodies on either side of the vaginal opening and to the rear of the vestibular bulbs. They sometimes get infected and swell, at which point you can feel them. They produce a few drops of fluid during sexual arousal.
All the way in…
Remember that the cervix is the base of the uterus (the womb). The nonpregnant uterus is about the size of a small fist. Its thick walls contain some of the most powerful muscles in the body. It is located behind the bladder, which is beneath the abdominal wall, and in front of the rectum, which is near the backbone. The walls of the uterus touch each other unless pushed apart by a growing fetus or an abnormal growth. The top of the uterus is called the fundus.
Extending outward and back from the sides of the upper end of the uterus are the two fallopian tubes (or oviducts; literally, “egg tubes”). They are approximately four inches long and look like ram’s horns facing backward or single quotation marks. The connecting opening from the inside of the uterus to the fallopian tube is as small as a fine needle. The other end of the tube is fringed (fimbriated) and funnel-shaped. The wide end of the funnel wraps part way around the ovary but does not actually attach to it. It is held in place by connecting tissues.
The ovaries are organs about the size and shape of unshelled almonds or large grapes, located on either side of and somewhat below the uterus. They are about four or five inches below your waist. They are held in place by connective tissue and are protected by a surrounding mass of fat. They have two functions: 1) to produce eggs; and 2) to produce hormones such as estrogen, progesterone, and testosterone. The small gap between the ovary and the end of the corresponding tube allows the egg to float freely after it has been released from the ovary. The fingerlike ends (fimbria) of the fallopian tube sweep across the surface of the ovary and wave the egg into the tube after ovulation.
Written by: Marianne McPherson. Adapted from the Sexual Anatomy chapter of the 1998 edition of OBOS.
Last revised: January 2005
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