Anatomy

Vulva

The vulva is a composite name for the external genitalia. It includes the mons veneris, the labia majora and minora, the clitoris, the entrance to the vagina, the hymen, and the vestibule anatomy: but the term is ill-define and many regards it as covering deeper structures such as the vestibular bulbs and Bartholin’s glands as well For convenience, the perineum is considered with the vulva. Anatomy

Individual Structures:

Mons veneris and labia majora

• The mons is the hair-bearing skin and the fatty pad which overlie the upper part of the symphysis pubis and the lower abdominal muscles, it acts as a coital buffer. Anatomy extending backwards from the mons on either side of the vaginal orifice, are the labia majora which are folds of skin with underlying deposits of fat. These are homologous to the scrotum. Posteriorly they merge into each other and into the perineal skin. Their outer aspects are covered with hair, and their inner is smooth and moistened by the secretions of sebaceous and other glands. Except where the labia minora intervene, the inner surfaces ordinarily lie in contact with each other and thus close the entrance to the vagina.

• The mons and labia majora are covered with coarse skin which contains hair follicles, sebaceous glands, and sweat glands. Some of the latter are large, coiled, and specialized and are known as apocrine glands; these are only found in certain areas of the body such as the axilla and vulva, and their secretion (when modified by bacteria) gives rise to a characteristic odor which is of sexual significance.

• Some gynecologists regard the perineum as part of the vulva, and many include under this term the purines body (central tendon of the perineum) as well as the overlying skin. To anatomists, perineum’ means all structures within the bony outlet of the pelvis.

• In view of their structure, the mons and labia: Majora are exposed to ordinary diseases of the skin including conditions such as psoriasis, sebaceous cysts, boils, carbuncles, and new growths Because the underlying connective tissue is very loose, the labia readily become oedematous

Perineum

The perineum comprises less hairy skin and subcutaneous tissue which lie between the vaginal orifice and the anus and cover the muscular perineal body. Its length from before backward varies from 2 to 5cm or more. influences the resistance it offers and the injuries it sustains during childbirth. The median raphe seen in the male is usually, but not always, absent in the female, this being explained by slight differences in development. Unlike the rest of the vulva, the perineum has very little subcutaneous fat so the skin is close to the underlying muscles.

Labia minora (nymphae)

Labia minora are delicate flaps of soft skin lying within the labia majora, one on each side of the vaginal orifice, and are homologous to the floor of the penile urethra in the male. They vary considerably in size and may be hidden by the labia majora or may protect between them. Ordinarily, their inner surfaces lie in contact with each other and their outer surfaces are in contact with the labium majus on the same side.

Anteriorly the labia minora join together and in so doing split to provide the clitoris with a prepuce and frenulum. They join posteriorly to form a sharp fold of skin. the fourchette and they also merge into the labia majora. The fourchette is nearly always injured during childbirth and sometimes suffers slight tearing during the first attempts at coitus. The depression between the fourchette and hymen which is found in virgins is the fossa navicularis.

The labia minora each consists of two layers of non-keratinized skin with some intervening loose connective tissue. The latter is devoid of fat but is so vascular that it enables the labia to become turgid under conditions of sexual excitement. They also contain sebaceous glands, especially near their bases, but few, if any, sweat glands.

Clitoris

The clitoris is the homolog of the penis and is a small structure lying on the front of the symphysis almost hidden by the foreparts of the labia majora. It has a glans, prepuce, body, and two crura (corpora cavernosa) which attach it to the pubic bones. The clitoris consists of erectile tissue richly supplied with nerves which make it the most

erotically sensitive part of the vulva. Smegma is secreted beneath the prepuce Only the glans and prepuce are visible. But the body is palpable against the symphysis pubis as a small cord-like structure approximately 2cm in length

Vestibule

The definition of the vestibule (from the Latin restibulum meaning a forecourt or a hall next to the entrance) varies but generally. The term is apply only to the area of smooth skin lying within the labia minora and in front of the vaginal orifice. The urethra opens onto it. On either side of the urethral meatus are tiny depressions call part-urethral pouches with adjacent insignificant folds- the urethral labia.

Hymen

The hymen is a delicate incomplete membrane guarding the entrance to the vagina prior to maturity and sexual experience It has one or more apertures to allow the outflow of menstrual blood and, according to their number and shape, is describe as being annular, crescent- tic, septate or cribriform. Unless the opening is

unusually large, and the hymen itself particularly elastic, coitus nearly always causes tearing The tear is most commonly find posteriorly or posterolaterally. It is one of the signs of loss of virginity but is not a very reliable one because injuries may be cause by operations, digital interference, or the insertion of tampons to contain the menstrual discharge. Moreover, coitus can take place without a tear resulting Inspection alone is often insufficient to permit a conclusion. If a hymen is intact and unstretched; a better clinical test is to feel gently for its resistant edge with the tip of the finger.

The hymen is relatively avascular so it’s tearing usually causes only a slight loss of blood. During childbirth the hymen is destroy, its remains being a few tags around the vaginal orifice carunculae myrtiformes.

Vestibular bulb.

The two bulbs are collections of erectile tissue which together are homologous to the corpus

spongiosum in the male. Each passes backwards from the root of the clitoris, lying deep to the bulbospongiosus (bulbocavernosus) muscle (sphincter vaginae). But superficial to the lower layer of the triangular ligament (urogenital diaphragm). The compressor urethrae (external urethral sphincter) and the deep transverse perineal muscles.

Bartholin’s glands (greater vestibular glands)

Bartholin’s glands are two in number and are homologous to Cowper’s glands in the male. They lie posterolaterally to the vaginal orifice, embedded in the posterior part of the vestibular bulb. Each gland is oval in shape and approximately the size of a pea. But is impalpable unless hardened or enlarged by disease, Its duct is 1.25-2cm in length. And runs downwards and inwards to open at the introitus below. The hymen but above the attachment of the posterior end of the labium minus. The orifice of the duct is not normally visible but,

when

the duct and gland are infect, may be indicate by a small red area.

The gland is lobulate and racemose, the acini being line by a single layer of low columnar or cuboidal cells. The duct is line by multilayere columnar cells and not by transitional epithelium, as is usually state. The impression of the latter is create by a study of pathological states. Thus the surface columnar cells become flatten when the duct is distende to form a cyst, and infection may sometimes result in metaplasia anatomy.

The secretion of the gland is colorless and mucoid and has a characteristic odor. It is produce mainly in response to sexual excitement when considerable amounts are pour onto the vulva to act as a lubricant for coitus. The gland continues limited activity after anatomy menopause.

Changes in the vulva with age and parity

The tissues of the vulva are sensitive to sex hormones, especially estrogens, so their anatomy

d function changes with age and the endocrine anatomy environment.

In infancy and childhood, the mons veneris and Dia Majora are devoid of hair. In the very young the labia majora are plump and tend to secure the tiny nymphae, but the vaginal orifice is seen surprisingly easily when the legs are anatomy abducte. Later, the labia lose their fat so the lab minors and the editors are relatively pro and protruding During childhood the skin of all the tissues is thin and delicate, and that of the vestibule is reddish in color. Fat reappears in the mons and labia majora as part of sexual development in adolescence, and the labia minora and vaginal orifice then become hidden. The growth of pubic hair is an early sign of puberty

The effect of coitus on the hymen has already been describe. The fourchette and the perineum are frequently torn during childbirth and thereafter appear scar Deep tearing may leave the perineum shorter than it was originally, and the vaginal orifice then becomes wider and more expose because of the separation of the posterior parts of the labia majora.

In old age, all the tissues atrophy and the skin becomes drier, thinner, and glazed. The subcutaneous fat is lessen except in obese women The labia minora shrink and may almost dis- appear. The vaginal orifice tends to contract Pubic hair becomes sparse.

Relations

An understanding of the relations of the vulva rests on an appreciation of the position of its component parts in relation to the bony pelvis. and this is illustrate.

Vascular connexions:

All the tissues of the vulva are extremely vascular, so even a minor operation in that area should not be attempt except in well-equip surroundings anatomy.

Arterial

The vulva is mainly supply by branches of the internal pudendal artery, which is one of the two terminal branches of the internal iliac artery, but its foreparts are also serve by the superficial external pudendal artery.

Venous

Some veins accompany corresponding arteries to the internal pudendal vein; those of the clitoris and bulb link with the vesical and vaginal plexuses. The long saphenous vein also takes a share of the venous return so its ligature can improve vulval varicosities anatomy.

Lymphatic

Drainage is mainly to the superficial inguinal nodes, and thence to the deep inguinal and external iliac nodes. Lymphatics from the deep tissues accompany the internal pudendal vessels to the internal iliac nodes. Anatomy