Female External Genital Anatomy
The 'Vulva' or the female external genital organs, are those genital organs that are present on the surface of the female body and can be easily examined. These are also known as the female sexual organs.
The Vulva consists of the mons pubis, the labia majora, labia minor, clitoris, vestibule and glands like the Bartholin's glands, Skene's glands and the Vestibular Glands. The perinuem - the area between the vulva and the anus - is also considered to be a part of the female external genital organs.
The other female genital organs are the internal genital organs consisting of the vagina, uterus, the two fallopian tubes and the two ovaries. Ligaments like the broad ligaments are also included among the female internal genital organs.
The breasts, are considered to be the accessssory organs of reproduction.
From front to back, the part of the vulva which is easily visible is the mons pubis which extend downwards into the two labia majora.
The other organs are enclosed between the labia majora. They are the two thin labia minora, the clitoris, the vestibule, the external urethral meatus, the vaginal opening covered with a hymen in virgins and a number of glands like the Bartholin's glands and the vestibular glands.
The mons pubis (also called mons venereum or mount of Venus) is the rounded fatty mass over the pubic bone covered with coarse hair and thick skin. It acts as a buffer during sexual intercourse, preventing injury to the underlying pelvic bone. The Mons also contains sebaceous and sweat glands. Some of the latter form a specialized type of gland called the apocrine glands. These glands release a secretion containing chemicals known as pheromones with a characteristic smell that increases sexual attraction.
The 'Vulva' - Clitoris, Labia Major, Labia Minora, Mons pubis, Vagina
Before menstruation starts in a young girl, the mons pubis contains less fat and is considerably flattened and hairless. At the time of puberty, the release of estrogen and progesterone from the developing Graafian follicles in the ovaries causes the laying down of fat in this area. Hormones from the adrenal cortex stimulates the growth of pubic hair on the mons pubis, as well as in the external surface of the labia major and the perineum.
After menopause, the pubic hair becomes thinner, coarser and starts greying. The mons loses the pad of fat. In a very elderly woman, even the labia majora and minora may become thin and flattened.
Labia MajoraThe labia majora are bilateral folds of skin and underlying fat extending backwards from the mons pubis. They are homologous to the scrotum in males. Posteriorly they merge into the perineum in front of the anus. Their outer surface becomes covered with hair at puberty. But the inner surface remains smooth, moistened by the secretions from the sebaceous and other glands deep inside. The labia majora also contain apocrine glands.
In a young girl, before the onset of menstruation, the labia majora are thinner with less fat and a fine smooth skin. Hair growth over the labia majora is one of the first signs of maturity of of a young girl. It coincides with the growth of Graafian follicles in the ovaries.
In women in menopause, the labia majora becomes thinner with less fat and considerable hair loss.
The labia minora, also known as the inner labia, inner lips, or nymphae, are delicate flaps of soft skin which lie within the labia majora. They fold and protect the opening of the vagina, the urethra, and the clitoris. They may be of different sizes in different women and if large enough, may protrude from between the labia majora. Their inner surfaces remain in contact with each other. Anteriorly, they unite to enclose the clitoris between them, forming the prepuce and frenulum from before backwards. The labia minora contains no fat but are so vascular that they become turgid during sexual stimulation. They are very sensitive to touch and pressure.
Since the labia are very thin and delicate, they can get torn during labor and childbirth causing heavy bleeding. Bleeding can continue even in the postpartum period and postpartum infections are a common occurance.
The vestibule is the part of the vulva lying between the two labia minora. It has two important openings - (a) the external urethral opening which is a small slit-like opening just behind the clitoris (b) the vaginal opening which is a larger opening behind the urethral opening. In virgins, the opening of the vagina is covered by a thin incomplete membrane, called the 'hymen'.
Injuries during labor occurs commonly in the vestibular region, especially the paraurethral region.
The clitoris is present in the upper part of the vestibule at the point where the two labia minor meet. It is a small cylindrical structure homologous to the penis in males. Like the male penis, it also has a glans, a prepuce and two corpora cavernosa which are attached to the pubic bones. The clitoris is made up of erectile tissue and is richly supplied with nerves, making it the most erotically sensitive part of the body.
The hymen is a thin membrane situated at the opening of the vagina and partially covering it. It can be of different shapes and sizes. It is commonly seen in the shape of a ring around the vaginal opening. Sometimes it may be semilunar with its concave margin turned toward the clitoris. Occasionally it may even be cribriform or netlike - several small openings in a more or less complete membrane. Rarely it may be completely absent.
In a condition known as the Imperforate hymen, the hymen forms a thick membrane completely covering the vaginal opening. It prevents the flow of blood and discharge during the period and needs to be excised when a girl attains puberty.
These are small pea-sized glands situated inside the vestibule on either side of the vaginal opening. They produce a mucoid secretion at times of sexual excitement that help to lubricate the vagina and vulva. The duct from the gland to the vagina may sometimes get blocked, forming what is known as a Bartholin's cyst. This cyst may need to be drained and excised if it causes discomfort. Bartholin's abscess occurs when the cyst gets infected.
They are embedded in the mucous membrane of the vestibule and are composed of erectile tissue.
The perineum is the less hairy cutaneous area lying between the vaginal orifice in front and the anus behind.