Anatomy and Physiology
The vagina is a thin-walled tube 8 to 10 cm long. It lies between the bladder and rectumand extends from the cervix to the body exterior. Often called the birth canal, the vagina providesa passageway for the delivery of an infant and for the menstrual flow to leave the body. The cervix (from Latin “neck”) is the lower, narrow portion of the uterus where it joinswith the top end of the vagina.
Approximately half its length is visible with appropriate medical equipment; the remainder liesabove the vagina beyond view. It is occasionally called “cervix uteri”, or “neck of the uterus”. During menstruation, the cervix stretches open slightly to allow the endometrium to beshed. This stretching is believed to be part of the cramping pain that many women experience. Evidence for this is given by the fact that some women’s cramps subside or disappear after their first vaginal birth because the cervical opening has widened.
The portion projecting into the vagina is referred to as the portio vaginalis or ectocervix. On average, the ectocervix is three cm long and two and a half cm wide. It has a convex,elliptical surface and is divided into anterior and posterior lips. The ectocervix’s opening is calledthe external os. The size and shape of the external os and the ectocervix varies widely with age,hormonal state, and whether the woman has had a vaginal birth. In women who have not had avaginal birth the external os appears as a small, circular opening.
During childbirth, contractions of the uterus will dilate the cervix up to 10 cm in diameter to allow the child to pass through. During orgasm, the cervix convulses and the external osdilates. The uterus is shaped like an upside-down pear, with a thick lining and muscular walls. Located near the floor of the pelvic cavity, it is hollow to allow a blastocyte, or fertilized egg, toimplant and grow. It also allows for the inner lining of the uterus to build up until a fertilized eggis implanted, or it is sloughed off during menses. The uterus contains some of the strongest muscles in the female body.
These muscles areable to expand and contract to accommodate a growing fetus and then help push the baby outduring labor. These muscles also contract rhythmically during an orgasm in a wave like action. It20 is thought that this is to help push or guide the sperm up the uterus to the fallopian tubes wherefertilization may be possible. The uterus is only about three inches long and two inches wide, but during pregnancy itchanges rapidly and dramatically. The top rim of the uterus is called the fundus and is alandmark for many doctors to track the progress of a pregnancy.
It is only after all alternative options have been considered that surgery isrecommended in these cases. This surgery is called hysterectomy. Hysterectomy is the removalof the uterus, and may include the removal of one or both of the ovaries. Once performed it isirreversible. After a hysterectomy, many women begin a form of alternate hormone therapy dueto the lack of ovaries and hormone production. The Fallopian tubes are paired, tubular, seromuscular organs whose course runs mediallyfrom the cornua of the uterus toward the ovary laterally. The tubes are situated in the upper margins of the broad.