- Related Topics:
- obstetric fistula
- vaginitis
- hymen
- rectocele
- gynecological examination
- On the Web:
- National Library of Medicine - Physiology, Vaginal (Oct. 19, 2026)
vagina
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What is the vagina?
The vagina is a muscular canal in female mammals that serves as the receptacle for sperm during sexual intercourse and as part of the birth canal during childbirth. In humans, it also functions as an excretory canal for menstrual products.
In humans, the vagina is approximately 3.5 inches (9 cm) long and is positioned in front of the rectum and behind the bladder. The upper region connects to the cervix of the uterus. The muscle walls of the vagina are thick and elastic, allowing for expansion during intercourse and childbirth. The walls of the vagina comprise two layers of muscle fibers: a weak internal circular layer and a strong external longitudinal layer. The mucous membrane that lines the vagina has longitudinal ridges in both the anterior and posterior walls.
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Where is the vagina located in the human body?
The vagina is a canal that extends from the cervix of the uterus to the vestibule, located between the labia minora. It sits within the lesser pelvis, behind the bladder and urethra, and in front of the rectum and anal canal. The vagina's walls are typically collapsed, with the anterior wall measuring about 7.5 cm (3 inches) and the posterior wall around 9 cm (3.6 inches) long.
The vagina is positioned obliquely upward and backward, forming an angle of over 90° with the uterus. The cervix projects into the vagina, creating recesses known as the posterior fornix, lateral fornices, and anterior fornix.
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What are the main functions of the vagina?
The vagina is a muscular canal in female mammals with several key functions. It receives sperm during sexual intercourse and connects to the cervix of the uterus. The vagina serves as part of the birth canal during childbirth. Additionally, it functions as an excretory canal for menstrual products. The mucus that lubricates the vaginal cavity protects against disease-causing microorganisms.
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How does the vagina change during puberty and adulthood?
During puberty, the vagina, uterus, and labia enlarge, and the vaginal walls thicken. Estrogen increases vaginal acidity, reducing bacterial infections.
During adulthood, the vagina experiences slow and gradual changes. After menopause, decreased estrogen levels can cause the vaginal lining to become thin and dry. The vaginal secretion diminishes, but these effects can be reversed with estrogen administration.
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Why is cleanliness and health important for the vagina, and how can it be maintained?
Maintaining cleanliness and health is crucial for the vagina due to its susceptibility to infections like vaginitis and vulvitis. The vagina's warm, moist environment can breed bacteria, fungi, and viruses, leading to inflammation and infection.
Good hygiene practices, such as wearing loose, absorbent underwear and avoiding irritating products like scented soaps or douches, can help prevent these issues. The vagina naturally maintains a slightly acidic environment, thanks to glycogen-producing bacteria, which protects against harmful microorganisms.
Infections can be treated with antimicrobial drugs, while hormonal changes, such as those occurring after menopause, may require hormone replacement therapy to maintain a healthy vaginal lining.
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vagina, canal in female mammals that receives the male reproductive cells, or sperm, and is part of the birth canal during the birth process. In humans, it also functions as an excretory canal for the products of menstruation.
In humans the vagina is about 9 cm (3.5 inches) long on average; it is located in front of the rectum and behind the bladder. The upper region of the vagina connects to the cervix of the uterus. The vaginal channel is narrowest at the upper and lower ends. In most virgins, the external opening to the vagina is partially closed by a thin fold of tissue known as the hymen. The opening (vaginal orifice) is partially covered by the labia majora.
The muscle walls of the vagina are thick and elastic in order to accommodate both the movement of the penis during intercourse and the passage of a child during delivery. The muscular wall is composed of two layers of muscle fibres, a weak internal circular layer and a strong external longitudinal layer. Covering the muscle tissue is a sheath of connective tissue that consists of blood vessels, lymphatic ducts, and nerve fibres. This layer of connective tissue joins those tissues of the urinary bladder, rectum, and other pelvic structures.
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The lining of the vaginal cavity responds to stimulation from the various ovarian hormones by either building new cell layers or shedding the old ones. The thickness of the lining varies directly with the amount of estrogen liberated from the ovaries; the lining is thickest and most elastic during ovulation (egg release from the ovaries) and during pregnancy. The vaginal lining characteristically has several transverse ridges known as vaginal rugae, which permit expansion of the vaginal cavity. These tend to disappear in older women and in those women who have borne children.
There are no glands in the vaginal wall. The mucus that lubricates the vaginal cavity had traditionally been ascribed to the cervix or to the Bartholin’s glands in the labia. After extensive clinical observation, however, William H. Masters and Virginia Johnson reported in 1966 that vaginal lubrication during sexual excitement was supplied by the seepage of a mucuslike fluid through the walls of the vagina. The cells in the lining contain large quantities of glycogen (stored animal starch). Bacteria within the vagina ferment the glycogen, so that lactic acid is produced. The lactic acid makes the surface of the lining slightly acidic, thus protecting against disease-causing microorganisms that have gained entry via the vaginal orifice.
Various diseases and disorders can affect the vagina. Conditions associated with infection include leukorrhea and vaginitis, which can be caused by organisms such as yeast and bacteria. Other conditions are ulcerated sores, prolapse (in which the internal portions of the vagina protrude out of the vaginal orifice), and occasionally cancerous tumours.