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The external genitals form the vulva. Under this name are included the mons veneris, the labia majora, the labia minora, the clitoris, the vestibule, the hymen and the glands of Bartholin.

The entire groove from the mons veneris to a point well up on the sacrum forms a deep fold or crevice, which is known as the genital crease. That part of the genital crease lying between the anus and vulva is technically known as the perineum (q.v.)

Fig. 6.—The external genitals. (Redrawn from Gray.)

The Mons Veneris.—The mons veneris is a gently rounded pad of fat lying just above the junction of the pubic bones (the symphysis). The overlying integument is filled with sebaceous glands and covered with hair at puberty.

The Labia Majora.—The labia majora are the large lips of the vulva. They are loose, double folds of skin extending downward from the mons veneris to the anterior boundary of the perineum and covered externally with hair. Normally they lie in apposition and conceal the vaginal opening. They correspond to the male scrotum.

The Labia Minora.—The labia minora, or nymphæ, are two small folds of skin and mucous membrane, that extend from the clitoris obliquely downward and outward for an inch and a half on each side of the entrance to the vagina. On the upper side, where they meet and invest the clitoris, the fold is called the prepuce, but on the under side they constitute the frænum.

The labia minora are sometimes enormously enlarged in the black races and are then called the Hottentot apron.

The Clitoris.—The clitoris is an erectile structure analogous to the erectile tissue of the penis. The free extremity is a small, rounded, extremely sensitive tubercle, called the glans of the clitoris. About the clitoris there forms a whitish substance called smegma. This is a good culture medium for germs and must be carefully sponged away when the vulva is prepared for delivery.

The Vestibule.—The vestibule is bounded by the clitoris above, the labia minora on the sides, and the vaginal orifice below. It contains the opening of the urethra, which is called the meatus urinarius.

The Hymen.—The hymen is a thin fold of membrane which closes the vaginal opening to a greater or lesser extent in virgins. It varies much in shape and consistency. It is sometimes absent, or it may persist after copulation, hence its presence or absence can not be considered a test of virginity. When torn, the edges shrink up and form little irregularities called carunculæ myrtiformes.

Fig. 7 A.—Varieties of hymen. (American Text Book.)

Bartholin Glands.—Bartholin glands are located on each side of the commencement of the vagina. Each gland discharges by a small duct just external to the hymen. They are often the seat of a chronic gonorrhœal inflammation and must be watched carefully, lest infection extend to the mother after labor, or to the eyes of the child in passing.

Fig. 7 B.—Varieties of hymen. (American Text Book.)

The Perineum.—The perineum is a body of muscle, fascia, connective tissue, and skin, situated between the vagina and the rectum. The vagina bends forward and the rectum backward, so a triangular area is left between them which is filled by the perineal body. It is about two inches long from before backward, and becomes progressively thinner the deeper it extends.

Fig. 8 A.—The excreting ducts of the mammary gland. (Lenoir and Tarnier.)

Fig. 8 B.—Lobules and duct of the mammary gland. (Lenoir and Tarnier.)

The perineal body is flattened out and compressed by the passage of the head and in many cases torn. (Thirty per cent of primiparas and ten to fifteen per cent of multiparas.) It should be repaired immediately.

The Mammary Glands.—The mammary glands are secondary but highly important parts of the genital system. They are formed by a dipping down of skin glands and they perform the special function of secreting milk.

The breast is made up of fifteen or twenty lobes, each of which, like a bunch of grapes, clusters about and discharges into a single tube which, in turn, leads to the nipple. The area between the lobes is filled with fat and connective tissue.

Fig. 9.—Nipple, areola, and the glands of Montgomery. (Eden.)

The nipple is pink or darkly pigmented. It is composed of erectile tissue and under stimulation, it rises from the surface of the gland so that it is easily taken into the mouth.

Fig. 10.—Supernumerary milk glands in the axillæ. They may be found also below the breasts. (Witkowski.)

Fig. 11.—The three ages of the breast—virginity, maturity, and senescence. (Witkowski.)

Surrounding the nipple is a darkly pigmented area from one inch to four inches in diameter that is called the areola. It contains hard, shot-like nodules, the glands, or tubercles, of Montgomery. These often secrete milk and sometimes become infected. It occasionally happens that more than two breasts may be found on the human female, and not infrequently pieces of mammary tissue may be discovered in the axilla or on the chest or back.

The mammary gland is undeveloped at birth, but, nevertheless it may fill with milk (witches’ milk). At puberty, after marriage, and during pregnancy, the gland reaches maturity. It is only after delivery, however, that the functional climax is attained.