CHAPTER II.
PARTS CONTAINED IN THE PELVIS.
The internal organs of generation are the vagina and uterus with its appendages; but I will first describe the urethra and the perineum.
The URETHRA is a membranous dilatable canal about an inch and a half in length, and directed obliquely from before backwards, and from below upwards, running under and behind the symphasis pubis, from which it is separated by loose celular tissue. Its inferior portion is intimately united to the vaginal walls. Its meatus, the outlet for the urine, is situated about an inch from the clitoris, and immediately above the prominent enlargement of the anterior part of the vagina.
Internally the urethra opens into the bladder. Its direction is subject to variation during pregnancy, the bladder being carried upwards with the uterus, the urethra curves under the pubic arch, and then ascends perpendicularly. The same change occurs when the uterus is enlarged from other causes. In prolapse of the pelvic viscera the course is reversed.
The PERINEUM is the portion between the rectum and the vagina.
THE UTERUS.
The uterus is the organ provided for the reception, growth, and ultimately for the expulsion of the fœtus. In the virgin normal state it is pear-shaped, flattened from before backwards; is situated in the cavity of the pelvis, between the bladder and the rectum, and projects into the upper end of the vagina below. Its upper end or base is directed upwards and forwards, so that its axis corresponds very nearly with that of the superior strait, and forms an angle with the vagina.
The uterus measures about three inches in length, at its upper part two in breadth, an inch in thickness, and it weighs from one ounce to an ounce and a half. The _fundus_ is the upper broad extremity of the organ; it is convex, covered by peritoneum, and placed in a line below the level of the brim of the pelvis. The _body_ gradually narrows from the fundus to the neck. Its anterior surface is flattened, covered by peritoneum in the upper three-fourths of its extent, and separated from the bladder by some convolutions of the small intestines; the lower fourth is connected with the bladder. Its posterior surface is convex, covered by peritoneum throughout, and separated from the rectum by some convolutions of the intestines. The lateral margins are concave, and give attachment to the Fallopian tubes above or superiorly, and the round ligaments below; and behind these, and also below the ligament of the ovary. The _cervix_ is the lower and constricted portion of the uterus; around its circumference is attached the upper end of the vagina, and this extends upwards a greater distance behind than in front. At the vaginal extremity of the uterus is a transverse aperture, the OS UTERI, bounded by two lips, an anterior one which is thick, and a posterior one, narrow and long. The os uteri, or os tincæ, is generally about the size of a small goose-quill. The _canal of the cervix_ is from half to three-quarters of an inch long; leading from the os uteri it first widens and then contracts again where it enters the body of the uterus. The surface of the canal exhibits a variable number of follicles or vesicles called the _glandula nabothi_, which secrete a thick mucus; this blocks the canal after impregnation. The cavity of the body and neck has a longitudinal extent of about two and a half inches; in virgins it is much less. (Fig. 12).
STRUCTURE OF THE UTERUS.
The proper tissue of the womb is composed of fibres, and is proved to be muscular. In the unimpregnated state it is dense, firm, and of a grayish color. The neck appears less firm than the body.
The _internal or mucous membrane_ is thin, smooth, and closely adherent to the subjacent tissue. It is a quarter of an inch thick at the middle of the body of the uterus; in the neck it does not exceed one-twenty-fourth part of an inch in thickness. It is continuous through the fimbriated extremity of the Fallopian tubes with the peritoneum, and through the os uteri with the mucous membrane of the vagina.
THE FALLOPIAN TUBES.
The uterine or Fallopian tubes are two canals, about four inches long, placed in the superior border of the broad ligaments of the uterus. They extend for about three inches and a half, when they expand and terminate with a fringed process called the fimbria, which is applied to the ovary after impregnation. The Fallopian tubes serve the double purpose of a canal for transmitting the fecundating principle of the male and for carrying the germ furnished by the female to the uterus—in fact they are excretory ducts of the ovary.
Injections into the uterus may pass into the peritoneal cavity, through the Fallopian tubes, and cause peritonitis.
At each menstrual period an ovula passes along with the serum current in the Fallopian tubes to the uterus.
THE OVARIES.
The ovaries in the female are said to be the analogues of the testicles in the male; they both secrete a fluid that is essential to impregnation. They are situated on either side of the uterus, and are attached to either side of it by the posterior duplicature of the broad ligament called the ligament of the ovary. (Fig. 12).
They are oval flattened bodies about an inch and a half long, three-quarters of an inch wide at their greatest breadth, and a quarter of a inch thick. They are situated on the sides of the uterus in that portion of the broad ligament called the posterior wing, just behind the Fallopian tubes. The ovary consists of a peculiar structure enclosed by two envelopes, one of which is serous and the other fibrous. Within the fibrous coat is a special tissue called the stroma; imbedded in this are numerous small round transparent vesicles in various stages of development, varying in size from that of a millet seed to that of a hemp seed. They are the ovisacs, containing the ova, and are called the Graafian vesicles. These have thin transparent walls and contain a clear fluid, and within that the ovula. Fifteen or twenty may readily be distinguished in the adult female without the aid of magnifying glasses.
THE VAGINA.
The vagina is a membranous canal, extending from the vulva to the uterus obliquely through the pelvic cavity, between the bladder and rectum, having about the same direction as the axis of the pelvis. It is described as being five or six inches in length and about two inches in diameter, but it would be more correct to say that it is capable of being distended to these or greater dimensions, for in its common state the os uteri is seldom found to be more than three inches from the external orifice, and the vagina is contracted as well as shortened. In great part the walls of the vagina are composed of spongy erectile tissue, and their vascularity is a cause of considerable hemorrhage consequent on their rupture. Three layers combine to form the walls; one external or cellulo-fibrous, a middle or muscular one, and the internal or mucous one. The latter is of a pale red hue, which becomes violet during menstruation and especially during pregnancy. The mucous coat is disposed in the form of rugæ or folds anteriorly and posteriorly, which are better developed in young virgins and aged females; during advanced pregnancy, and for a short time after delivery, they are entirely effaced.
The upper part of the vagina is connected to the circumference of the os uteri but not in a straight line, for the former stretches beyond the latter, and being joined to the cervix, its mucous membrane is reflected over the os uteri, which by this mode of union is suspended with protuberant lips in the vagina, and permitted to change its position in various ways and directions.
THE EXTERNAL ORGANS.
The situation of the external organs of generation are indicated in the accompanying diagram (Fig. 11.) It is not deemed necessary here to describe these, but in regard to the hymen (the membrane that in infancy nearly closes the orifice of the vagina), we may remark that it is not a perfect test of virginity. There are, however, examples recorded in works on midwifery where a slight surgical operation was necessary after marriage, because this membrane was uncommonly strong.