The opening of the vagina is surrounded by female external genitalia that is called the vulva. Known as vulvae in the plural form, vulvar meaning is the collective term used for labia majora, labia minora, vestibule of the vagina, the clitoris, bulb of the vestibule, and the glands of Bartholin. These female organs are located below the mons pubis (the bulk of fatty tissue present at the forward pelvic bone junction) and in front of the anus. Every girl vulva is different in shape and size.
The external area of the labia is covered with sebaceous (oil-secreting) glands and pigmented skin. After puberty, it gets covered with coarse hair. The insides of the vulva region are smooth, hairless, with sweat glands. Underneath the skin layer of the vulva, there is primarily fatty tissue with a few ligaments, nerves, smooth muscle fibres, blood, and lymphatic vessels.
1. Labia Majora
Two thick folds of skin that go from the mons pubis to the anus are the labia majora. They are the outer set of folds and they are large and hairy. The part that is labia majora in females, corresponds to the scrotum in males. The small structure of erectile tissue under the mons pubis and between the labia majora is called the clitoris.
During sexual excitement, there is increased blood pressure which causes enlargement of the clitoris which is smaller in scale as compared to the male penis in structure. The clitoris does not have a urethra for excretion of urine like the penis. It has a rounded tissue elevation at its tip called the glans clitoridis. The glans clitoridis is located at the top of the vulva, where the labia minora meet. It is different for every female, varying in size and shape. A clitoral hood covers the tip of the clitoris. The clitoris consists of spongy tissue that gets engorged when stimulated. It has more nerve endings.
3. Labia Minora
On two sides of the glans clitoridis, there are the starting folds of the labia minora. The labia minora creates a fold or a hood where it meets at the top of the vagina. This fold is called the prepuce (foreskin) of the clitoris. The vestibule of the vagina is surrounded by labia minora, which is the two folds of skin between the labia majora. These folds do not have fat or hairs and their skin is moist, smooth, and pink with sebaceous and sweat glands. The labia minora also meets just below the vaginal opening, and that part is called the fourchette. The anus which is the rectum opening is beyond the fourchette and is the part from where the stool is excreted out of the body. The perineum is a gap between the anus and the vagina.
4. Other Parts of the Vulva
The vaginal vestibule starts below the clitoris and has openings of the vagina, the urethra, along with the ducts of the two glands of Bartholins. The opening of the urethra is like a small slit present close to the clitoris. This opening is used for urine excretion. Under this opening, there is a larger opening called the vaginal orifice that has the opening of the two Bartholin ducts on each of its sides. These glands often contract an infection and secrete mucus that acts as a lubricant for the vagina at the time of sexual activity.
The diameter of each gland is about 1 cm (0.4 inches) and after a female turns 30, the size of these glands goes down slightly. A membranous fold of skin called the hymen surrounds and almost covers the vaginal orifice. Sometimes a variety of activities can cause the stretch or tear in the hymen. Two elongated erectile tissue structures known as the bulb of the vestibule are present alongside the vestibule. The vestibule area also has several mucous glands and the vestibule is covered by both labia majora and labia minora.
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Fig 1.1 Diagram of the vagina
Blood Supply to the Vulva
The vulva gets its blood supply from the three pudendal arteries. The pudendal nerve, peroneal nerve, ilioinguinal nerve, and their branches supply the vulva. The internal pudendal veins provide drainage. It is the nerve and blood supply to the vulva that helps in sexual arousal that aids in the reproduction process.
Most women experience a painful vulva or a sore vulva at some point. If the pain persists for more than 3 months and there is no apparent cause behind it as per the diagnosis, the condition is called vulvodynia. It can occur at any age but in most cases, it occurs in women between the age of 20 to 40. Sometimes the pain occurs in the entire vulvar region and sometimes it is there only in the lips of the vulva.