The Grafenberg spot (G-spot) and female ejaculation are two controversial issues in the field of human sexuality. The G-spot, first described by Ernest Grafenberg in 1950, is a spot about the size of a dime or quarter in the lower third of the front part of the vagina and is particularly sensitive to stimulation (Whipple, 2000). The G-spot is found about 2 or 3 inches up the anterior (front or stomach) side of the vagina, just past the pubic bone (see Figure 4.3). There is some controversy over whether this spot is a separate physiological entity, with some arguing that the entire anterior wall (and even parts of the posterior wall) of the vagina is generally sensitive (Alzate & Hoch, 1986). Others argue that the G-spot is homologous to the male prostate.
Stimulating the G-spot causes pleasant vaginal sensation in some women and can result in powerful orgasms accompanied by the forceful expulsion of fluid (female ejaculation). Women may ejaculate up to 4 ounces of fluid, which may come from the Skenes glands on either side of the urethra (Heath, 1984); however, some researchers argue that female ejaculate is chemically indistinguishable from urine (Alzate, 1985).
The Uterus
The uterus is a thick-walled, hollow, muscular organ in the pelvis sandwiched between the bladder in front and the rectum behind. It is approximately the shape of an inverted pear, with a dome-shaped top (fundus), a hollow body, and the doughnut-shaped cervix at the bottom. The uterus provides a path for sperm to reach the ovum, undergoes a cycle of change every month that leads to menstruation, nourishes and protects the fetus during gestation, and provides the contractions for expulsion of the mature fetus during labor. The uterus is about 3 inches long and flares to about 2 inches wide, but it increases greatly in size and weight during and after a pregnancy and atrophies after menopause.
The uterine wall is about 1 inch thick and is made up of three layers (see Figure 4.3). The outer layer, or perimetrium, is part of the tissue that covers most abdominal organs. The muscular layer of the uterus, the myometrium, contracts to expel menstrual fluid and to push the fetus out of the womb during delivery. The inner layer of the uterus, the endometrium, responds to fluctuating hormonal levels, and its outer portion is shed with each menstrual cycle.
The Cervix. The cervix (SERV-ix) is the lower portion of the uterus that contains the opening, or os, leading into the body of the uterus. It is through the os that menstrual fluid flows out of the uterus and that sperm gain entrance. Glands of the cervix secrete mucus with varying properties during the monthly cycle; during ovulation, the mucus helps sperm transport through the os, and during infertile periods, it can block the sperm from entering. During childbirth, the cervix softens and the os dilates to allow the baby to pass through. The cervix can be seen with a mirror during a pelvic exam, and women should not hesitate to ask their gynecologist or other medical professional to show it to them. The cervix can also be felt at the top end of the vagina.