Читать книгу Obstetrical Nursing - Carolyn Conant Van Blarcom - Страница 10

The female organs of reproduction are divided into two groups, the internal and the external genitals. With them are usually considered certain other structures: the ureters, bladder, urethra, rectum and the perineum, because of their close proximity (Fig. 10.); and the breasts, because of their functional relation to the reproductive organs.

Internal Genitalia. The internal organs of generation are contained in the true pelvic cavity and comprise the uterus and vagina in the centre, an ovary and Fallopian tube on each side, together with their various ligaments, membranes, nerves and blood vessels and a certain amount of fat and connective tissue.

The uterus is the largest of these organs. In its nonpregnant state, it is a hollow, flattened, pear-shaped organ about three inches long, one and a quarter inches wide, at its broadest point, three-quarters of an inch thick and weighing about two ounces.

Fig. 10.—Anterior view of female generative tract, showing both external and internal organs. Drawn by Max Brodel. (Used by permission of A. J. Nystrom & Co., Chicago.)

Ordinarily it is a firm, hard mass, consisting of irregularly disposed, involuntary (unstriped or plain) muscle fibres and connective tissue, nerves and blood vessels. The arrangement of the uterine muscle fibres is unique, for they run up and down, around and crisscross, forming a veritable network. This strange arrangement of the fibres is favorable to the growth of the uterine musculature during pregnancy, and a factor in preventing hemorrhage after delivery.

The abundant blood supply to the uterus merits a word. It is derived from the uterine arteries, arising from the internal iliacs, and the ovarian artery from the aorta. The arteries from the two sides of the uterus are united by a branch where the neck and body of this organ meet, thus forming an encircling artery. A deep cervical tear during labor may break this vessel and a profuse hemorrhage occur as a result.

Fig. 11.—Diagrams of sections of virgin and multiparous uteri.

The uterus is covered, front and back, by a fold of the peritoneum, except the lower part of the anterior wall where the peritoneum is reflected up over the bladder. It is lined with a thick, velvety, highly vascular mucous membrane, the endometrium, the surface of which is covered by ciliated, columnar epithelium. Embedded in the endometrium are numerous mucous glands which dip down into the underlying, muscular wall.

The uterus as a whole is comprised of three parts: the fundus, that firm, rounded, head-like part above; the body, or middle portion, and the cervix, or neck, below. It is in the body and cervix that we find the long, narrow uterine cavity, divided by a constriction into two parts. The cavity of the body is little more than a vertical slit, being so flattened from before backward that the anterior and posterior surfaces are nearly if not quite in apposition. It is somewhat triangular in shape with an opening at each angle. (Fig. 11.) The lower of these openings leads into the cavity of the cervix through a constriction termed the internal os, while at the cornua, or two upper angles, are the openings into the Fallopian tubes.

The cavity of the cervix is spindle-shaped, being expanded between its two constricted openings, the internal os above and the external os below, which opens into the vagina. The external os in the virgin is a small round hole but has a ragged outline in women who have borne children.

This oblong, muscular body, the uterus, is suspended obliquely in the centre of the pelvic cavity by means of ligaments. In its normal position the entire organ is slightly curved forward, or ante-flexed, the fundus being directed upward and forward and the cervix pointing down and back. This position is affected by a distended bladder or rectum, and also by postural changes in the body as a whole. The cervix protrudes into the anterior wall of the vagina for about one-half inch and almost at right angles, since the vagina slopes down and forward to the outlet.

The upper part of the uterus is held in position by means of ligaments, the lower part being embedded in fat and connective tissue between the bladder and rectum. This more or less of a floating position makes possible the enormous increase in size and upward push or extension of the uterus during pregnancy. The pregnant uterus becomes soft and elastic as it grows. At term it is about a foot long, eight to ten inches wide, and reaches up into the epigastric region. This growth is due in part to the development of new muscle fibres and in part to a growth of the fibres already existing in the uterine wall.

After labor the uterus returns almost, but never entirely, to its former size, shape and general condition.

The Fallopian tubes are two tortuous, muscular tubes, four or five inches long, extending laterally in an upward curve, from the cornua of the uterus and within the folds of the upper margin of the broad ligament, by which they are covered. At their juncture with the uterus, the diameter of these tubes is so small as to admit of the introduction of only a fine bristle, but they gradually increase in size toward their termination in wide trumpet-shaped orifices, which open directly into the peritoneal cavity. Finger-like projections called fimbriæ, fringe the margins of these openings.

The mucous lining of the tubes is covered with ciliated epithelium and is continuous with that of the uterus. At the fimbriated extremities of the tubes this lining merges into the peritoneum, the serous lining of the abdominal cavity.

Just here it will be well to say a word about the peritoneum because of the possibility of its becoming infected during labor and the lying-in period, and the very grave consequences of such infection. It is a delicate, highly vascular, serous membrane which both lines the abdominal cavity and covers the abdominal and pelvic organs, which press into its outer surface and are covered much as one’s fingers would be covered by pushing them into the outer surface of a child’s toy balloon. The continuity of this membrane is broken only where it is entered by the Fallopian tubes.

The ovary, the sex gland of the female, is a small, tough ductless gland, about an inch long and three-quarters of an inch wide, or about the size and shape of an almond. It is greyish pink in color and presents a more or less irregular, dimpled surface. An ovary is suspended on either side of the uterus, in the posterior fold of the broad ligament, by which it is partly covered. Its outer end is usually attached to the longest of the fimbriated extremities of the Fallopian tube, the fimbria ovarica, which has the form of a shallow gutter, or groove. The inner end of the ovary is attached to the ovarian ligament, which in turn is attached to the uterus below and behind the tubal entrance.

The ovary consists of two parts, the central part or medulla, composed of connective tissue, nerves, blood and lymph vessels, and the cortex, in which are embedded the vesicular Graafian follicles containing the ova. At birth each ovary contains upwards of 50,000 of these ova, which are the germ cells concerned with reproduction and the process of menstruation.

These ovarian glands perform two vital functions, for in addition to their prime function of producing and maturing the germinal cell of the female, they provide an internal secretion which exercises an immeasurably important, though imperfectly understood, influence upon the general well-being of the entire organism.

Fig. 12.—Sagittal section of female generative tract. Drawn by Max Brodel. (Used by permission of A. J. Nystrom & Co., Chicago.)

The vagina is an elastic, muscular sheath or tube, about four inches long, lying behind the bladder and urethra and in front of the rectum. It leads interiorly up and backward from the vulva to the cervix, which it encases for about half an inch. The space between the outer surface of the cervix that extends into the vagina, and the surrounding vaginal walls, is called the fornix. For convenience of description, this is divided into four sections or fornices: the anterior, posterior and lateral fornices.

Between the posterior fornix and the rectum a fold of the peritoneum drops down and forms a blind pouch known as Douglas’ cul-de-sac. At this point the delicate peritoneum is separated from the vagina by only a thin, easily punctured, muscular wall. This is a fact of grave surgical significance, for unless instruments and nozzles introduced into the vagina are very gently and skillfully directed, they may easily pierce this thin partition. Septic material may thus gain entrance to the peritoneal cavity and peritonitis result.

The bore of the vaginal canal ordinarily permits of the introduction of one or two fingers. It is somewhat flattened from before backward, and on cross section resembles the letter H. During labor this canal becomes enormously dilated, being then four or five inches in diameter, and permits the passage of the full term child.

The vagina is lined with a thick, heavy, mucous membrane which normally lies in transverse folds or corrugations called rugæ. These folds are obliterated and the lining stretched into a smooth surface as the canal dilates during labor.

Attention must be drawn to the fact that the vagina, cervix, uterus and tubes form a continuous canal from the vulva to the easily infected peritoneum, a fact which makes absolute surgical cleanliness in obstetrics virtually a matter of life or death to the patient.

This muscular tube is lined throughout its entire length with mucous membrane, which, though continuous, changes somewhat in character along its course. The epithelial cells of the lining of the tubes and body of the uterus have hair-like projections, cilia, which maintain a constant waving motion from above downward. The effect of this sweeping current is to carry down toward the outlet any object or secretion which may be upon the surface of the lining of the tubes or uterine cavity. The unfertilized ovum is thus swept down to meet the germ cell of the male and become fertilized.

Along this variously constructed canal, at different periods in the life of the individual, pass the matured ovum, the menstrual flow, the uterine secretions, the fetus, the placenta and lochia, (the discharge which occurs during the puerperium).

Although the bladder and rectum are not organs of reproduction, they are contained in the pelvic cavity and lie in such close proximity to the internal genitalia that at least a passing word must be devoted to their description.

The bladder is a sac of connective tissue which serves as a reservoir for the urine and is situated behind the symphysis pubis and in front of the uterus and vagina. Urine is conducted into the bladder by the ureters, two slender tubes running down on each side from the basin of the kidney across the pelvic brim to the upper part of the bladder, which they enter somewhat obliquely, at about the level of the cervix. It is thought that pressure of the enlarged pregnant uterus upon the ureters at this point may be one factor in the causation of pyelitis, a frequent complication of pregnancy. The bladder empties itself through the urethra, a short tube which terminates in the meatus urinarius, a tiny opening in the vulva.

The rectum, the lowest segment of the intestinal tract, is situated in the pelvic cavity behind and to the left of the uterus and vagina. It extends downward from the sigmoid flexure of the colon to its termination in the anal opening. The anus is a deeply pigmented, puckered opening situated an inch and a half or two inches behind the vagina. It is guarded by two bands of strong circular muscles, the internal and external sphincter ani. The skin covering the surface of the body extends upward into the anus where it becomes highly vascular and merges into the mucous lining of the rectum. Pressure exerted during pregnancy by the enlarged uterus is felt in both the rectum and bladder, frequently causing a good deal of discomfort and almost painful desire to evacuate their contents.

The blood vessels in the anal lining just within the external sphincter sometimes become engorged and inflamed, even bleeding during pregnancy, as a result of the pressure exerted by the greatly enlarged uterus. The distended blood vessels, which in this condition are called hemorrhoids, not infrequently protrude from the anus and become very painful.

After having considered the structure and relative positions of the pelvic organs one is able to picture more clearly the arrangement and disposition of the uterine ligaments, all of which are formed by folds of the peritoneum. They are twelve in number, five pairs and two single ligaments, namely: two broad, two round, two utero-sacral, two utero-vesical, two ovarian, one anterior and one posterior ligament.

The broad ligaments are in reality one continuous structure formed by a fold of the peritoneum, which drops down over the uterus, investing the fundus, body, part of the cervix, and part of the posterior wall of the vagina. It unites on each side of the uterus to form a broad, flat membrane which extends laterally to the pelvic wall, dividing the pelvic basin into an anterior and posterior compartment, containing respectively the bladder and rectum. Between the folds of the broad ligament are situated the ovaries and ovarian ligaments, the Fallopian tubes, the round ligaments and a certain amount of muscle and connective tissue, blood vessels, lymphatics and nerves.

The round ligaments, one on each side, are narrow, flat bands of connective tissue derived from the peritoneum and muscle prolonged from the uterus, and containing blood and lymph vessels and nerves. They pass upward and forward from their uterine origin just below and in front of the tubal entrance, finally merging in the mons veneris and labia majora.

The utero-sacral ligaments, of which there is one on each side, arise in the uterus and, extending backward, serve to connect the cervix and vagina with the sacrum.

The utero-vesical ligaments, one on each side, extend forward and connect the uterus and bladder.

The ovarian ligaments, as previously described, are attached to the uterine wall and to the inner end of the ovary, one on each side.

The anterior ligament is a portion of the peritoneum which dips down between the bladder and uterus, forming a pouch. It is known also as the uterine-vesical pouch, or the vesico-uterine excavation.

The posterior ligament is formed in much the same manner by a portion of the peritoneum dipping down behind the uterus, in front of the rectum, and forming the recto-vaginal pouch. This is the Douglas’ cul-de-sac previously referred to.

External Genitalia.—The vulva, or external genitalia, are situated in the pudendal crease which lies between the thighs at their junction with the torso, and extends posteriorly from the pubis to a point well up on the sacrum. (Fig. 13.)

The mons veneris is a firm cushion of fat and connective tissue, just over the symphysis pubis. It is covered with skin which contains many sebaceous glands and after puberty is abundantly covered with hair.

Fig. 13.—Diagram of external female genitalia. (Redrawn from Dickinson.)

The labia majora are heavy ridges of fat and connective tissue, prolonged from the mons veneris and extended down and back almost to the rectum, on each side, forming the lateral boundaries of the groove. They are lined with mucous membrane and covered with skin and hair, the latter growing thinner toward the perineum until it finally disappears.

The labia minora are two small cutaneous folds lying between the labia majora on each side of the vagina. Like the larger folds, they taper toward the back and practically disappear in the vaginal wall. Their attenuated posterior ends are joined together behind the vagina by means of a thin, flat fold called the fourchette. The labia minora divide for a short distance before joining at an angle in front, thus forming a double ridge anteriorly. In the depression between these ridges is the clitoris, a small, sensitive projection composed of erectile tissue, nerves and blood vessels and covered with mucous membrane. The meatus urinarius is just below the clitoris and between two small folds of the mucous membrane.

The vestibule is the triangular space between the labia minora, and into it open the meatus urinarius, the vagina and the more important vulvo-vaginal glands.

The vaginal opening is below the vestibule and above the perineum. It is partially closed by the hymen, a fold of mucous membrane disposed irregularly around the outlet, somewhat after the fashion of a circular curtain. The hymen is ragged or more or less scalloped in outline, and varies greatly in size in different women, in some instances extending so far over the opening as nearly or quite to close it.

The fossa navicularis is a depressed space between the hymen and fourchette, so named because of its boat-like shape.

The Bartholin glands, probably the largest and most important of the vulvo-vaginal glands, are situated one on each side of the vagina and open into the groove between the hymen and labia minora. Reference is made to these glands because of the danger of their becoming infected. A gonorrheal infection of these glands is particularly troublesome.

The perineum is a pyramidal structure of connective tissue and muscle which occupies the space between the rectum and vagina, and by forming the floor of the pelvis serves as a support for the pelvic organs. The lower and outer surface of this mass, representing the base of the pyramid, lies between the vaginal opening and the anus and is covered with skin. As the anterior part of the perineum is incorporated in the posterior wall of the vagina, the entire structure becomes stretched and flattened when the vagina is dilated during labor by the passage of the child’s head.

Unless very carefully guarded at the time of delivery, and often even then, the perineum gives way under the great tension undergone at that time, and a tear is the result. The injury may be only a slight nick in the mucous membrane or it may extend to, or into the levator ani, the most important muscle of the perineal body, or if a “complete tear” will extend all the way through the perineum and completely through the sphincter ani. Such a tear is lamentable, as a break in the ring-shaped sphincter muscle guarding the anal opening robs a woman of control of her bowels, and is repaired with difficulty.