1. Female reproductive system. Structure, position and function of ovary. Uterus, development, shape, parts, structure and topography. Uterine tubes

2. Structure and topography of vagina, external reproductive organs and urethra. Topography of small pelvis organs on female

3. Perineal muscles and fasciae on male and female. Radiograph anatomy of urinary and reproductive organs

Lesson No 17

Theme 1. Female reproductive system. Structure, position and function of ovary. Uterus, development, shape, parts, structure and topography. Uterine tubes.

                    Genital Glands. The first appearance of the genital gland is essentially the same in the two sexes, and consists in a thickening of the epithelial layer which lines the peritoneal cavity on the medial side of the urogenital fold. The thick plate of epithelium extends deeply, pushing before it the mesoderm and forming a distinct projection. This is termed the genital ridge, and from it the testis in the male and the ovary in the female are developed. At first the mesonephros and genital ridge are suspended by a common mesentery, but as the embryo grows the genital ridge gradually becomes pinched off from the mesonephros, with which it is at first continuous, though it still remains connected to the remnant of this body by a fold of peritoneum, the mesorchium or mesovarium. About the seventh week the distinction of sex in the genital ridge begins to be perceptible.

            The Ovary.—The ovary, thus formed from the genital ridge, is at first a mass of cells derived from the celomic epithelium; later the mass is differentiated into a central part or medulla covered by a surface layer, the germinal epithelium. Between the cells of the germinal epithelium a number of larger cells, the primitive ova, are found, and these are carried into the subjacent stroma by bud-like ingrowths (genital cords) of the germinal epithelium. The surface epithelium ultimately forms the permanent epithelial covering of this organ; it soon loses its connection with the central mass, and a tunica albuginea develops between them. The ova are chiefly derived from the cells of the central mass; these are separated from one another by the growth of connective tissue in an irregular manner; each ovum assumes a covering of connective tissue (follicle) cells, and in this way the rudiments of the ovarian follicles are formed. According to Beard the primitive ova are early set apart during the segmentation of the ovum and migrate into the germinal ridge.

           Waldeyer taught that the primitive germ cells are derived from the “germinal epithelium,” covering the genital ridge. Beard, on the other hand, maintains that in the skate they are not derived from this epithelium, but are probably formed during the later stages of cell cleavage, before there is any trace of an embryo; and a similar view was advanced by Nussbaum as to their origin in amphibia. Beard says: “At the close of segmentation many of the future germ cells lie in the segmentation cavity just beneath the site of the future embryo, and there is no doubt they subsequently wander into it.” The germ cells, “after they enter the resting phase, are sharply marked off from the cells of the embryo by entire absence of mitoses among them.” They can be further recognized by their irregular form and ameboid processes, and by the fact that their cytoplasm has no affinity for ordinary stains, but assumes a brownish tinge when treated by osmic acid. The path along which they travel into the embryo is a very definite one, viz., “from the yolk sac upward between the splanchnopleure and gut in the hinder portion of the embryo.” This pathway, named by Beard the germinal path, “leads them directly to the position which they ought finally to take up in the `germinal ridge' or nidus.” A considerable number apparently never reach their proper destination, since “vagrant germ cells are found in all sorts of places, but more particularly on the mesentery.” Some of these may possibly find their way into the germinal ridge; some probably undergo atrophy, while others may persist and become the seat of dermoid tumors.

            Descent of the Ovaries. In the female there is also a gubernaculum, which effects a considerable change in the position of the ovary, though not so extensive a change as in that of the testis. The gubernaculum in the female lies in contact with the fundus of the uterus and contracts adhesions to this organ, and thus the ovary is prevented from descending below this level. The part of the gubernaculum between the ovary and the uterus becomes ultimately the proper ligament of the ovary, while the part between the uterus and the labium majus forms the round ligament of the uterus. A pouch of peritoneum analogous to the saccus vaginalis in the male accompanies it along the inguinal canal: it is called the canal of Nuck. In rare cases the gubernaculum may fail to contract adhesions to the uterus, and then the ovary descends through the inguinal canal into the labium majus, and under these circumstances its position resembles that of the testis.

Fallopian tubes. The fallopian tubes are about 10 cm long and begin as funnel-shaped passages next to the ovary. They have a number of finger-like projections known as fimbriae on the end near the ovary. When an egg is released by the ovary it is caught by one of the fimbriae and transported along the fallopian tube to the uterus. The egg is moved along the fallopian tube by the wafting action of cilia hairy projections on the surfaces of cells at the entrance of the fallopian tube and the contractions made by the tube. It takes the egg about 5 days to reach the uterus and it is on this journey down the fallopian tube that fertilisation may occur if a sperm penetrates and fuses with the egg. The egg, however, is only usually viable for 24 hours after ovulation, so fertilisation usually occurs in the top one-third of the fallopian tube.

Uterus
The uterus is a hollow cavity about the size of a pear (in women who have never been pregnant) that exists to house a developing fertilised egg. The main part of the uterus (which sits in the pelvic cavity) is called the body of the uterus, while the rounded region above the entrance of the fallopian tubes is the fundus and its narrow outlet, which protrudes into the vagina, is the cervix.

The thick wall of the uterus is composed of 3 layers. The inner layer is known as the endometrium. If an egg has been fertilised it will burrow into the endometrium, where it will stay for the rest of its growth. The uterus will expand during a pregnancy to make room for the growing fetus. A part of the wall of the fertilised egg, which has burrowed into the endometrium, develops into the placenta. If an egg has not been fertilised, the endometrial lining is shed at the end of each menstrual cycle.

The myometrium is the large middle layer of the uterus, which is made up of interlocking groups of muscle. It plays an important role during the birth of a baby, contracting rhythmically to move the baby out of the body via the birth canal (vagina).

Uterus

"Hystera" and "Uterine" redirect here. For the state of mind, see hysteria. "Womb"

The uterus (from Latin "uterus", plural uteri) or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species. Two uteri usually form initially in a female fetus, and in placental mammals they may partially or completely fuse into a single uterus depending on the species. In many species with two uteri, only one is functional. Humans and other higher primates usually have a single completely fused uterus, although in some individuals the uteri may not have completely fused. In English, the term uterus is used consistently within the medical and related professions, while the Germanic-derived term womb is more common in everyday usage.

The uterus consists of a body and a cervix. The cervix protrudes into the vagina. The uterus is held in position within the pelvis by condensations of endopelvic fascia, which are called ligaments. These ligaments include the pubocervical, transverse. cervical ligaments cardinal ligaments, and the uterosacral ligaments. It is covered by a sheet-like fold of peritoneum, the broad ligament.[2]

The uterus is essential in sexual response by directing blood flow to the pelvis and to the external genitalia, including the ovaries, vagina, labia, and clitoris.

The reproductive function of the uterus is to accept a fertilized ovum which passes through the utero-tubal junction from the fallopian tube. It implants into the endometrium, and derives nourishment from blood vessels which develop exclusively for this purpose. The fertilized ovum becomes an embryo, attaches to a wall of the uterus, creates a placenta, and develops into a fetus (gestates) until childbirth. Due to anatomical barriers such as the pelvis, the uterus is pushed partially into the abdomen due to its expansion during pregnancy. Even during pregnancy the mass of a human uterus amounts to only about a kilogram (2.2 pounds).

Humans may have a bicornuate uterus, a uterine malformation where the two parts of the uterus fail to fuse completely during fetal development.

The uterus is located inside the pelvis immediately dorsal (and usually somewhat rostral) to the urinary bladder and ventral to the rectum. The human uterus is pear-shaped and about 3 in. (7.6 cm) long. The uterus can be divided anatomically into four segments: The fundus, corpus, cervix and the internal os.

Regions

From outside to inside, the path to the uterus is as follows:

·                    Cervix uteri - "neck of uterus"

o        External orifice of the uterus

o        Canal of the cervix

o        Internal orifice of the uterus

·                    corpus uteri - "Body of uterus"

o        Cavity of the body of the uterus

o        Fundus (uterus)

Layers

The three layers, from innermost to outermost, are as follows:

Endometrium

The lining of the uterine cavity is called the "endometrium". It consists of the functional endometrium and the basal endometrium from which the former arises. Damage to the basal endometrium results in adhesion formation and/or fibrosis (Asherman's syndrome

). In all placental mammals, including humans, the endometrium builds a lining periodically which is shed or reabsorbed if no pregnancy occurs. Shedding of the functional endometrial lining is responsible for menstrual bleeding (known colloquially as a "period" in humans, with a cycle of approximately 28 days, +/-7 days of flow and +/-21 days of progression) throughout the fertile years of a female and for some time beyond. Depending on the species and attributes of physical and psychological health, weight, environmental factors of circadian rhythm, photoperiodism (the physiological reaction of organisms to the length of day or night), the effect of menstrual cycles to the reproductive function of the uterus is subject to hormone production, cell regeneration and other biological activities. The menstrual cycles may vary from a few days to six months, but can vary widely even in the same individual, often stopping for several cycles before resuming. Marsupials and monotremes do not have menstruation.

Myometrium

The uterus mostly consists of smooth muscle, known as "myometrium." The innermost layer of myometrium is known as the junctional zone, which becomes thickened in adenomyosis.

Parametrium

The loose connective tissue around the uterus.

Support

The uterus is primarily supported by the pelvic diaphragm, perineal body and the urogenital diaphragm. Secondarily, it is supported by ligaments and the peritoneum (broad ligament of uterus)

Axes

Normally the uterus lies in anteversion & anteflexion. Anteversion is a forward angle between the axis of the cervix and that of the vagina measuring about 90 degrees, provided the urinary bladder and the rectum are empty. Anteflexion is a forward angle between the body and cervix at the isthmus measuring about 125 degrees, provided the bladder and rectum are empty.

Major ligaments

It is held in place by several peritoneal ligaments, of which the following are the most important (there are two of each):

Name

From

To

Uterosacral ligament

Posterior cervix

Anterior face of sacrum

Cardinal ligaments

Side of the cervix

Ischial spines

Pubocervical ligament[4]

Side of the cervix

Pubic symphysis

Position

The uterus is in the middle of the pelvic cavity in frontal plane (due to ligamentum latum uteri). The fundus does not surpass the linea terminalis, while the vaginal part of the cervix does not extend below interspinal line. The uterus is mobile and moves under the pressure of the full bladder or full rectum anteriorly, whereas if both are full it moves upwards. Increased intraabdominal pressure pushes it downwards. The mobility is conferred to it by musculo-fibrous apparatus that consists of suspensory and sustentacular part. Under normal circumstances the suspensory part keeps the uterus in anteflexion and anteversion (in 90% of women) and keeps it "floating" in the pelvis. The meaning of these terms are described below:

Distinction

More common

Less common

Position tipped

"Anteverted": Tipped forward

"Retroverted

": Tipped backwards

Position of fundus

"Anteflexed": Fundus is pointing forward relative to the cervix

"Retroflexed": Fundus is pointing backwards

Sustentacular part supports the pelvic organs and comprises the larger pelvic diaphragm in the back and the smaller urogenital diaphragm in the front.

The pathological changes of the position of the uterus are:

·                    retroversion/retroflexion, if it is fixed

·                    hyperanteflexion - tipped too forward; most commonly congenital, but may be caused by tumors

·                    anteposition, retroposition, lateroposition - the whole uterus is moved; caused by parametritis or tumors

·                    elevation, descensus, prolapse

·                    rotation (the whole uterus rotates around its longitudinal axis), torsion (only the body of the uterus rotates around)

·                    inversion

In cases where the uterus is "tipped", also known as retroverted uterus, women may have symptoms of pain during sexual intercourse, pelvic pain during menstruation, minor incontinence, urinary tract infections, difficulty conceiving, and difficulty using tampons. A pelvic examination by a doctor can determine if a uterus is tipped.

Schematic diagram of uterine arterial vasculature seen as a cross-section through the myometrium and endometrium.

The uterus is supplied by arterial blood both from the uterine artery and the ovarian artery.

Nerve Supply

The nerves are derived from the hypogastric and ovarian plexuses, and from the third and fourth sacral nerves.

Development

The bilateral Müllerian ducts form during early fetal life. In males, MIF secreted from the testes leads to their regression. In females these ducts give rise to the Fallopian tubes and the uterus. In humans the lower segments of the two ducts fuse to form a single uterus, however, in cases of uterine malformations this development may be disturbed. The different uterine forms in various mammals are due to various degrees of fusion of the two Müllerian ducts.

    Vagina
The vagina is a fibromuscular tube that extends from the cervix to the vestibule of the vulva. The vagina receives the penis and semen during sexual intercourse and also provides a passageway for menstrual blood flow to leave the body.

The Metanephros and the Permanent Kidney.The rudiments of the permanent kidneys make their appearance about the end of the first or the beginning of the second month. Each kidney has a two-fold origin, part arising from the metanephros, and part as a diverticulum from the hind-end of the Wolffian duct, close to where the latter opens into the cloaca. The metanephros arises in the intermediate cell mass, caudal to the mesonephros, which it resembles in structure. The diverticulum from the Wolffian duct grows dorsalward and forward along the posterior abdominal wall, where its blind extremity expands and subsequently divides into several buds, which form the rudiments of the pelvis and calyces of the kidney; by continued growth and subdivision it gives rise to the collecting tubules of the kidney. The proximal portion of the diverticulum becomes the ureter. The secretory tubules are developed from the metanephros, which is moulded over the growing end of the diverticulum from the Wolffian duct. The tubules of the metanephros, unlike those of the pronephros and mesonephros, do not open into the Wolffian duct. One end expands to form a glomerulus, while the rest of the tubule rapidly elongates to form the convoluted and straight tubules, the loops of Henle, and the connecting tubules; these last join and establish communications with the collecting tubules derived from the ultimate ramifications of the diverticulum from the Wolffian duct. The mesoderm around the tubules becomes condensed to form the connective tissue of the kidney. The ureter opens at first into the hind-end of the Wolffian duct; after the sixth week it separates from the Wolffian duct, and opens independently into the part of the cloaca which ultimately becomes the bladder.

  The secretory tubules of the kidney become arranged into pyramidal masses or lobules, and the lobulated condition of the kidneys exists for some time after birth, while traces of it may be found even in the adult. The kidney of the ox and many other animals remains lobulated throughout life.

The External Organs of GenerationAs already stated, the cloacal membrane, composed of ectoderm and entoderm, originally reaches from the umbilicus to the tail. The mesoderm extends to the midventral line for some distance behind the umbilicus, and forms the lower part of the abdominal wall; it ends below in a prominent swelling, the cloacal tubercle. Behind this tubercle the urogenital part of the cloacal membrane separates the ingrowing sheets of mesoderm.

  The first rudiment of the penis (or clitoris) is a structure termed the phallus; it is derived from the phallic portion of the cloaca which has extended on to the end and sides of the under surface of the cloacal tubercle. The terminal part of the phallus representing the future glans becomes solid; the remainder, which is hollow, is converted into a longitudinal groove by the absorption of the urogenital membrane.

  In the female a deep groove forms around the phallus and separates it from the rest of the cloacal tubercle, which is now termed the genital tubercle. The sides of the genital tubercle grow backward as the genital swellings, which ultimately form the labia majora; the tubercle itself becomes the mons pubis. The labia minora arise by the continued growth of the lips of the groove on the under surface of the phallus; the remainder of the phallus forms the clitoris.

  In the male the early changes are similar, but the pelvic portion of the cloaca undergoes much greater development, pushing before it the phallic portion. The genital swellings extend around between the pelvic portion and the anus, and form a scrotal area; during the changes associated with the descent of the testes this area is drawn out to form the scrotal sacs. The penis is developed from the phallus. As in the female, the urogenital membrane undergoes absorption, forming a channel on the under surface of the phallus; this channel extends only as far forward as the corona glandis.

  The corpora cavernosa of the penis (or clitoris) and of the urethra arise from the mesodermal tissue in the phallus; they are at first dense structures, but later vascular spaces appear in them, and they gradually become cavernous.

  The prepuce in both sexes is formed by the growth of a solid plate of ectoderm into the superficial part of the phallus; on coronal section this plate presents the shape of a horseshoe. By the breaking down of its more centrally situated cells the plate is split into two lamellæ, and a cutaneous fold, the prepuce, is liberated and forms a hood over the glans. “Adherent prepuce is not an adhesion really, but a hindered central desquamation” (Berry Hart).

The Urethra.As already described, in both sexes the phallic portion of the cloaca extends on to the under surface of the cloacal tubercle as far forward as the apex. At the apex the walls of the phallic portion come together and fuse, the lumen is obliterated, and a solid plate, the urethral plate, is formed. The remainder of the phallic portion is for a time tubular, and then, by the absorption of the urogenital membrane, it establishes a communication with the exterior; this opening is the primitive urogenital ostium, and it extends forward to the corona glandis.

  In the female this condition is largely retained; the portion of the groove on the clitoris broadens out while the body of the clitoris enlarges, and thus the adult urethral opening is situated behind the base of the clitoris. In the male, by the greater growth of the pelvic portion of the cloaca a longer urethra is formed, and the primitive ostium is carried forward with the phallus, but it still ends at the corona glandis. Later it closes from behind forward. Meanwhile the urethral plate of the glans breaks down centrally to form a median groove continuous with the primitive ostium. This groove also closes from behind forward, so that the external urethral opening is shifted forward to the end of the glans.


 

 

The Mammæ (Mammary Gland; Breasts)

The mammæ secrete the milk, and are accessory glands of the generative system. They exist in the male as well as in the female; but in the former only in the rudimentary state, unless their growth is excited by peculiar circumstances. In the female they are two large hemispherical eminences lying within the superficial fascia and situated on the front and sides of the chest; each extends from the second rib above to the sixth rib below, and from the side of the sternum to near the midaxillary line. Their weight and dimensions differ at different periods of life, and in different individuals. Before puberty they are of small size, but enlarge as the generative organs become more completely developed. They increase during pregnancy and especially after delivery, and become atrophied in old age. The left mamma is generally a little larger than the right. The deep surface of each is nearly circular, flattened, or slightly concave, and has its long diameter directed upward and lateralward toward the axilla; it is separated from the fascia covering the Pectoralis major, Serratus anterior, and Obliquus externus abdominis by loose connective tissue. The subcutaneous surface of the mamma is convex, and presents, just below the center, a small conical prominence, the papilla.

  The Mammary Papilla or Nipple (papilla mammæ) is a cylindrical or conical eminence situated about the level of the fourth intercostal space. It is capable of undergoing a sort of erection from mechanical excitement, a change mainly due to the contraction of its muscular fibers. It is of a pink or brownish hue, its surface wrinkled and provided with secondary papillæ; and it is perforated by from fifteen to twenty orifices, the apertures of the lactiferous ducts. The base of the mammary papilla is surrounded by an areola. In the virgin the areola is of a delicate rosy hue; about the second month after impregnation it enlarges and acquires a darker tinge, and as pregnancy advances it may assume a dark brown or even black color. This color diminishes as soon as lactation is over, but is never entirely lost throughout life. These changes in the color of the areola are of importance in forming a conclusion in a case of suspected first pregnancy. Near the base of the papilla, and upon the surface of the areola, are numerous large sebaceous glands, the areolar glands, which become much enlarged during lactation, and present the appearance of small tubercles beneath the skin. These glands secrete a peculiar fatty substance, which serves as a protection to the integument of the papilla during the act of sucking. The mammary papilla consists of numerous vessels, intermixed with plain muscular fibers, which are principally arranged in a circular manner around the base: some few fibers radiating from base to apex.

Development.—The mamma is developed partly from mesoderm and partly from ectoderm—its bloodvessels and connective tissue being derived from the former, its cellular elements from the latter. Its first rudiment is seen about the third month, in the form of a number of small inward projections of the ectoderm, which invade the mesoderm; from these, secondary tracts of cellular elements radiate and subsequently give rise to the epithelium of the glandular follicles and ducts. The development of the follicles, however, remains imperfect, except in the parous female.

Structure—The mamma consists of gland tissue; of fibrous tissue, connecting its lobes; and of fatty tissue in the intervals between the lobes. The gland tissue, when freed from fibrous tissue and fat, is of a pale reddish color, firm in texture, flattened from before backward and thicker in the center than at the circumference. The subcutaneous surface of the mamma presents numerous irregular processes which project toward the skin and are joined to it by bands of connective tissue. It consists of numerous lobes, and these are composed of lobules, connected together by areolar tissue, bloodvessels, and ducts. The smallest lobules consist of a cluster of rounded alveoli, which open into the smallest branches of the lactiferous ducts; these ducts unite to form larger ducts, and these end in a single canal, corresponding with one of the chief subdivisions of the gland. The number of excretory ducts varies from fifteen to twenty; they are termed the tubuli lactiferi. They converge toward the areola, beneath which they form dilatations or ampullæ, which serve as reservoirs for the milk, and, at the base of the papillæ, become contracted, and pursue a straight course to its summit, perforating it by separate orifices considerably narrower than the ducts themselves. The ducts are composed of areolar tissue containing longitudinal and transverse elastic fibers; muscular fibers are entirely absent; they are lined by columnar epithelium resting on a basement membrane. The epithelium of the mamma differs according to the state of activity of the organ. In the gland of a woman who is not pregnant or suckling, the alveoli are very small and solid, being filled with a mass of granular polyhedral cells. During pregnancy the alveoli enlarge, and the cells undergo rapid multiplication. At the commencement of lactation, the cells in the center of the alveolus undergo fatty degeneration, and are eliminated in the first milk, as colostrum corpuscles. The peripheral cells of the alveolus remain, and form a single layer of granular, short columnar cells, with spherical nuclei, lining the basement membrane. The cells, during the state of activity of the gland, are capable of forming, in their interior, oil globules, which are then ejected into the lumen of the alveolus, and constitute the milk globules. When the acini are distended by the accumulation of the secretion the lining epithelium becomes flattened.

  The fibrous tissue invests the entire surface of the mamma, and sends down septa between its lobes, connecting them together.

  The fatty tissue covers the surface of the gland, and occupies the interval between its lobes. It usually exists in considerable abundance, and determines the form and size of the gland. There is no fat immediately beneath the areola and papilla.

Vessels and Nerves.—The arteries supplying the mammæ are derived from the thoracic branches of the axillary, the intercostals, and the internal mammary. The veins describe an anastomotic circle around the base of the papilla, called by Haller the circulus venosus. From this, large branches transmit the blood to the circumference of the gland, and end in the axillary and internal mammary veins. The nerves are derived from the anterior and lateral cutaneous branches of the fourth, fifth, and sixth thoracic nerves.

 

 

 

FEMALE GENITAL ORGANS are subdivided into

§  internal female sexual organs:

Ovaries, uterine tubes, uterus and vagina

§  external female genital organs:

Pudendal area with labia pudenda majora and labia pudenda minora, vestibule of vagina, clitoris and mons pubis.

The Ovary is a pair organ, is situated in cavity of lesser pelvis. It has medial surface and lateral surface, free margin and mesenteric margin, uterine extremity and tubarius extremity. Ovary is situated in peritoneal cavity, it is covered by embryonic epithelium (not by peritoneum). Ovary attaches to uterus by proper ovaric ligament, and to pelvis walls - by the medium of suspensory ovaric ligament. Ovaric mesentery approaches to anterior margin, through which the vessels and nerves get into ovary hilus. Ovary parenchyma consists of cortex and medulla. Ovule ripens in cortex, where primary folliculi are situated, which then transforms into Graaf vesicle. After that as vesicle blowes up, an oocyte gets out from the ovary and gets into uterine tube. Vesicle becomes as corpus luteum [yellow body]. If there is not fecundation, then corpus luteum transform into corpus albicans. In case of fecundation corpus luteum grows up and turns into corpus luteum verum, which functions during pregnancy.

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Uterus and right broad ligament, seen from behind. The broad ligament has been spread out and the ovary drawn downward.

 

The ovaries are homologous with the testes in the male. They are two nodular bodies, situated one on either side of the uterus in relation to the lateral wall of the pelvis, and attached to the back of the broad ligament of the uterus, behind and below the uterine tubes. The ovaries are of a grayish-pink color, and present either a smooth or a puckered uneven surface. They are each about 4 cm. in length, 2 cm. in width, and about 8 mm. in thickness, and weigh from 2 to 3.5 gm. Each ovary presents a lateral and a medial surface, an upper or tubal and a lower or uterine extremity, and an anterior or mesovarion and a posterior free border. It lies in a shallow depression, named the ovarian fossa, on the lateral wall of the pelvis; this fossa is bounded above by the external iliac vessels, in front by the obliterated umbilical artery, and behind by the ureter. The exact position of the ovary has been the subject of considerable difference of opinion, and the description here given applies to the ovary of the nulliparous woman. The ovary becomes displaced during the first pregnancy, and probably never again returns to its original position. In the erect posture the long axis of the ovary is vertical. The tubal extremity is near the external iliac vein; to it are attached the ovarian fimbria of the uterine tube and a fold of peritoneum, the suspensory ligament of the ovary, which is directed upward over the iliac vessels and contains the ovarian vessels. The uterine end is directed downward toward the pelvic floor, it is usually narrower than the tubal, and is attached to the lateral angle of the uterus, immediately behind the uterine tube, by a rounded cord termed the ligament of the ovary, which lies within the broad ligament and contains some non-striped, muscular fibers. The lateral surface is in contact with the parietal peritoneum, which lines the ovarian fossa; the medial surface is to a large extent covered by the fimbriated extremity of the uterine tube. The mesovarian border is straight and is directed toward the obliterated umbilical artery, and is attached to the back of the broad ligament by a short fold named the mesovarium. Between the two layers of this fold the bloodvessels and nerves pass to reach the hilum of the ovary. The free border is convex, and is directed toward the ureter. The uterine tube arches over the ovary, running upward in relation to its mesovarian border, then curving over its tubal pole, and finally passing downward on its free border and medial surface.

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Adult ovary, epoöphoron, and uterine tube. (From Farre, after Kobelt.) a, a. Epoöphoron formed from the upper part of the Wolffian body. b. Remains of the uppermost tubes sometimes forming hydatids. c. Middle set of tubes. d. Some lower atrophied tubes. e. Atrophied remains of the Wolffian duct. f. The terminal bulb or hydatid. h. The uterine tube. i. Hydatid attached to the extremity. l. The ovary.

Epoöphoron (parovarium; organ of Rosenmüller) lies in the mesosalpinx between the ovary and the uterine tube, and consists of a few short tubules (ductuli transversi) which converge toward the ovary while their opposite ends open into a rudimentary duct, the ductus longitudinalis epoöphori (duct of Gärtner).

 

Paroöphoron.—The paroöphoron consists of a few scattered rudimentary tubules, best seen in the child, situated in the broad ligament between the epoöphoron and the uterus.

  The ductuli transversi of the epoophoron and the tubules of the paroophoron are remnants of the tubules of the Wolffian body or mesonephros; the ductus longitudinalis epoöphori is a persistent portion of the Wolffian duct.

  In the fetus the ovaries are situated, like the testes, in the lumbar region, near the kidneys, but they gradually descend into the pelvis.

 

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Section of the ovary. (After Schrön.) 1. Outer covering. 1’. Attached border. 2. Central stroma. 3. Peripheral stroma. 4. Bloodvessels. 5. Vesicular follicles in their earliest stage. 6, 7, 8. More advanced follicles. 9. An almost mature follicle. 9’. Follicle from which the ovum has escaped. 10. Corpus luteum.

 



 

 

Structure. The surface of the ovary is covered by a layer of columnar cells which constitutes the germinal epithelium of Waldeyer. This epithelium gives to the ovary a dull gray color as compared with the shining smoothness of the peritoneum; and the transition between the squamous epithelium of the peritoneum and the columnar cells which cover the ovary is usually marked by a line around the anterior border of the ovary. The ovary consists of a number of vesicular ovarian follicles imbedded in the meshes of a stroma or frame-work.

  The stroma is a peculiar soft tissue, abundantly supplied with bloodvessels, consisting for the most part of spindle-shaped cells with a small amount of ordinary connective tissue. These cells have been regarded by some anatomists as unstriped muscle cells, which, indeed, they most resemble; by others as connective-tissue cells. On the surface of the organ this tissue is much condensed, and forms a layer (tunica albuginea) composed of short connective-tissue fibers, with fusiform cells between them. The stroma of the ovary may contain interstitial cells resembling those of the testis.

 

Vesicular Ovarian Follicles (Graafian follicles).—Upon making a section of an ovary, numerous round transparent vesicles of various sizes are to be seen; they are the follicles, or ovisacs containing the ova. Immediately beneath the superficial covering is a layer of stroma, in which are a large number of minute vesicles, of uniform size, about 0.25 mm. in diameter. These are the follicles in their earliest condition, and the layer where they are found has been termed the cortical layer. They are especially numerous in the ovary of the young child. After puberty, and during the whole of the child-bearing period, large and mature, or almost mature follicles are also found in the cortical layer in small numbers, and also “corpora lutea,” the remains of follicles which have burst and are undergoing atrophy and absorption. Beneath this superficial stratum, other large and more or less mature follicles are found imbedded in the ovarian stroma. These increase in size as they recede from the surface toward a highly vascular stroma in the center of the organ, termed the medullary substance (zona vasculosa of Waldeyer). This stroma forms the tissue of the hilum by which the ovary is attached, and through which the bloodvessels enter: it does not contain any follicles.

  The larger follicles consist of an external fibrovascular coat, connected with the surrounding stroma of the ovary by a net-work of bloodvessels; and an internal coat, which consists of several layers of nucleated cells, called the membrana granulosa. At one part of the mature follicle the cells of the membrana granulosa are collected into a mass which projects into the cavity of the follicle. This is termed the discus proligerus, and in it the ovum is imbedded. The follicle contains a transparent albuminous fluid.

  The development and maturation of the follicles and ova continue uninterruptedly from puberty to the end of the fruitful period of woman’s life, while their formation commences before birth. Before puberty the ovaries are small and the follicles contained in them are disposed in a comparatively thick layer in the cortical substance; here they present the appearance of a large number of minute closed vesicles, constituting the early condition of the follicles; many, however, never attain full development, but shrink and disappear. At puberty the ovaries enlarge and become more vascular, the follicles are developed in greater abundance, and their ova are capable of fecundation.

 

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Section of vesicular ovarian follicle

 

Discharge of the Ovum.—The follicles, after attaining a certain stage of development, gradually approach the surface of the ovary and burst; the ovum and fluid contents of the follicle are liberated on the exterior of the ovary, and carried into the uterine tube by currents set up by the movements of the cilia covering the mucous membrane of the fimbriae.

 

Corpus Luteum.—After the discharge of the ovum the lining of the follicle is thrown into folds, and vascular processes grow inward from the surrounding tissue. In this way the space is filled up and the corpus luteum formed. It consists at first of a radial arrangement of yellow cells with bloodvessels and lymphatic spaces, and later it merges with the surrounding stroma.

 

Vessels and Nerves.—The arteries of the ovaries and uterine tubes are the ovarian from the aorta. Each anastomoses freely in the mesosalpinx, with the uterine artery, giving some branches to the uterine tube, and others which traverse the mesovarium and enter the hilum of the ovary. The veins emerge from the hilum in the form of a plexus, the pampiniform plexus; the ovarian vein is formed from this plexus, and leaves the pelvis in company with the artery. The nerves are derived from the hypogastric or pelvic plexus, and from the ovarian plexus, the uterine tube receiving a branch from one of the uterine nerves.

The ovaries are homologous with the testes in the male. They are two nodular bodies, situated one on either side of the uterus in relation to the lateral wall of the pelvis, and attached to the back of the broad ligament of the uterus, behind and below the uterine tubes. The ovaries are of a grayish-pink color, and present either a smooth or a puckered uneven surface. They are each about 4 cm. in length, 2 cm. in width, and about 8 mm. in thickness, and weigh from 2 to 3.5 gm. Each ovary presents a lateral and a medial surface, an upper or tubal and a lower or uterine extremity, and an anterior or mesovarion and a posterior free border. It lies in a shallow depression, named the ovarian fossa, on the lateral wall of the pelvis; this fossa is bounded above by the external iliac vessels, in front by the obliterated umbilical artery, and behind by the ureter. The exact position of the ovary has been the subject of considerable difference of opinion, and the description here given applies to the ovary of the nulliparous woman. The ovary becomes displaced during the first pregnancy, and probably never again returns to its original position. In the erect posture the long axis of the ovary is vertical. The tubal extremity is near the external iliac vein; to it are attached the ovarian fimbria of the uterine tube and a fold of peritoneum, the suspensory ligament of the ovary, which is directed upward over the iliac vessels and contains the ovarian vessels. The uterine end is directed downward toward the pelvic floor, it is usually narrower than the tubal, and is attached to the lateral angle of the uterus, immediately behind the uterine tube, by a rounded cord termed the ligament of the ovary, which lies within the broad ligament and contains some non-striped, muscular fibers. The lateral surface is in contact with the parietal peritoneum, which lines the ovarian fossa; the medial surface is to a large extent covered by the fimbriated extremity of the uterine tube. The mesovarian border is straight and is directed toward the obliterated umbilical artery, and is attached to the back of the broad ligament by a short fold named the mesovarium. Between the two layers of this fold the bloodvessels and nerves pass to reach the hilum of the ovary. The free border is convex, and is directed toward the ureter. The uterine tube arches over the ovary, running upward in relation to its mesovarian border, then curving over its tubal pole, and finally passing downward on its free border and medial surface.

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Adult ovary, epoöphoron, and uterine tube. (From Farre, after Kobelt.) a, a. Epoöphoron formed from the upper part of the Wolffian body. b. Remains of the uppermost tubes sometimes forming hydatids. c. Middle set of tubes. d. Some lower atrophied tubes. e. Atrophied remains of the Wolffian duct. f. The terminal bulb or hydatid. h. The uterine tube. i. Hydatid attached to the extremity. l. The ovary.

Epoöphoron (parovarium; organ of Rosenmüller) lies in the mesosalpinx between the ovary and the uterine tube, and consists of a few short tubules (ductuli transversi) which converge toward the ovary while their opposite ends open into a rudimentary duct, the ductus longitudinalis epoöphori (duct of Gärtner).

 

 

The Uterine tube is a pair organ is situated in area of superior margin of ligamentum latum uteri. Length of each tube is 8-18 cm. There are 4 parts:

§  uterine part runs in wall of uterus and opens into uterine cavity by uterine ostium;

§  isthmus of uterine tube lies closely to uterus;

§  ampulla of uterine tube is greater part of uterine tube;

§  infundibulum of uterine tube - is broadened part, which opens by abdominal foramen of uterine tube into abdominal (peritoneal) cavity and covered by fimbria, one of which - ovaric fimbria is longer then other.

Uterine tube is covered from all sides by peritoneum and has its own mesentery. Tube has also muscular membrane (longitudinal and circular layers) and mucous membrane. Fecundation realizes in uterine tube normally, than fertilized ovule passes into uterus.

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Female pelvis and its contents, seen from above and in front.

 

The Uterus is an odd hollow organ, pear-shaped object, which is situated in cavity of lesser pelvis. It has a fundus, body and neck of uterus, which opens into vagina by uterine ostium, limited by anterior labium and posterior labium. Uterine neck divided into supravaginal portion and vaginal portion. Uterine body has vesical surface (anterior) and intestinal surface (posterior). Place of transition body of uterus into neck is called as isthmus. Anterior uterus surface adjoins to urinary bladder, and posterior - to rectum. Attached to empty urinary bladder body of uterus is tilted forward. Such position is called anteversio. Attached to full urinary bladder a fundus and uterus body displaces posteriorly – this is retroversio. Also between body and uterus neck is formed a angle, open forward. Such position is called anteflexio.

Triangle-shaped cavity of uterus above communicate with uterine tubes, and vagina through the cervical canal and ostium uteri.

Wall of uterus consists of three layers:

• mucous membrane (endometrium), submucous stratum is absent ,so there is no folds on internal surface of uterus;

• muscular membrane (myometrium) is formed by smooth muscle and consists of internal, middle and external layers;

• serous membrane (perimetrium) is a peritoneum, which covers an uterus from all sides, except part of front surface and lateral margins and supravaginal portion of neck (mesoperitoneal position). Serous membrane forms ligamentum uteri latum, which forms mesentery of uterus, mesentery of ovary and mesentery of uterine tube. Between sheets of ligamentum latum uteri the vessels, nerves, adipose tissue (parametrium) and ligamentum teres uteri are contained. Ligamentum teres [round] uteri passes through the inguinal canal to pubis. Also uterus is fixed to pelvic walls by cardinal ligament.

The uterus is a hollow, thick-walled, muscular organ situated deeply in the pelvic cavity between the bladder and rectum. Into its upper part the uterine tubes open, one on either side, while below, its cavity communicates with that of the vagina. When the ova are discharged from the ovaries they are carried to the uterine cavity through the uterine tubes. If an ovum be fertilized it imbeds itself in the uterine wall and is normally retained in the uterus until prenatal development is completed, the uterus undergoing changes in size and structure to accommodate itself to the needs of the growing embryo (see page 59). After parturition the uterus returns almost to its former condition, but certain traces of its enlargement remains. It is necessary, therefore, to describe as the type-form the adult virgin uterus, and then to consider the modifications which are effected as a result of pregnancy.

 

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Sagittal section of the lower part of a female trunk, right segment. SM. INT. Small intestine

 

  In the virgin state the uterus is flattened antero-posteriorly and is pyriform in shape, with the apex directed downward and backward. It lies between the bladder in front and the pelvic or sigmoid colon and rectum behind, and is completely within the pelvis, so that its base is below the level of the superior pelvic aperture. Its upper part is suspended by the broad and the round ligaments, while its lower portion is imbedded in the fibrous tissue of the pelvis.

  The long axis of the uterus usually lies approximately in the axis of the superior pelvic aperture, but as the organ is freely movable its position varies with the state of distension of the bladder and rectum. Except when much displaced by a fully distended bladder, it forms a forward angle with the vagina, since the axis of the vagina corresponds to the axes of the cavity and inferior aperture of the pelvis.

  The uterus measures about 7.5 cm. in length, 5 cm. in breadth, at its upper part, and nearly 2.5 cm. in thickness; it weighs from 30 to 40 gm. It is divisible into two portions. On the surface, about midway between the apex and base, is a slight constriction, known as the isthmus, and corresponding to this in the interior is a narrowing of the uterine cavity, the internal orifice of the uterus. The portion above the isthmus is termed the body, and that below, the cervix. The part of the body which lies above a plane passing through the points of entrance of the uterine tubes is known as the fundus.

 

Body (corpus uteri).—The body gradually narrows from the fundus to the isthmus.

  The vesical or anterior surface (facies vesicalis) is flattened and covered by peritoneum, which is reflected on to the bladder to form the vesicouterine excavation. The surface lies in apposition with the bladder.

  The intestinal or posterior surface (facies intestinalis) is convex transversely and is covered by peritoneum, which is continued down on to the cervix and vagina. It is in relation with the sigmoid colon, from which it is usually separated by some coils of small intestine.

  The fundus (fundus uteri) is convex in all directions, and covered by peritoneum continuous with that on the vesical and intestinal surfaces. On it rest some coils of small intestine, and occasionally the distended sigmoid colon.

  The lateral margins (margo lateralis) are slightly convex. At the upper end of each the uterine tube pierces the uterine wall. Below and in front of this point the round ligament of the uterus is fixed, while behind it is the attachment of the ligament of the ovary. These three structures lie within a fold of peritoneum which is reflected from the margin of the uterus to the wall of the pelvis, and is named the broad ligament.

 

Cervix (cervix uteri; neck).—The cervix is the lower constricted segment of the uterus. It is somewhat conical in shape, with its truncated apex directed downward and backward, but is slightly wider in the middle than either above or below. Owing to its relationships, it is less freely movable than the body, so that the latter may bend on it. The long axis of the cervix is therefore seldom in the same straight line as the long axis of the body. The long axis of the uterus as a whole presents the form of a curved line with its concavity forward, or in extreme cases may present an angular bend at the region of the isthmus.

  The cervix projects through the anterior wall of the vagina, which divides it into an upper, supravaginal portion, and a lower, vaginal portion.

  The supravaginal portion (portio supravaginalis [cervicis]) is separated in front from the bladder by fibrous tissue (parametrium), which extends also on to its sides and lateralward between the layers of the broad ligaments. The uterine arteries reach the margins of the cervix in this fibrous tissue, while on either side the ureter runs downward and forward in it at a distance of about 2 cm. from the cervix. Posteriorly, the supravaginal cervix is covered by peritoneum, which is prolonged below on to the posterior vaginal wall, when it is reflected on to the rectum, forming the rectouterine excavation. It is in relation with the rectum, from which it may be separated by coils of small intestine.

  The vaginal portion (portio vaginalis [cervicis]) of the cervix projects free into the anterior wall of the vagina between the anterior and posterior fornices. On its rounded extremity is a small, depressed, somewhat circular aperture, the external orifice of the uterus, through which the cavity of the cervix communicates with that of the vagina. The external orifice is bounded by two lips, an anterior and a posterior, of which the anterior is the shorter and thicker, although, on account of the slope of the cervix, it projects lower than the posterior. Normally, both lips are in contact with the posterior vaginal wall.

 

Interior of the Uterus—The cavity of the uterus is small in comparison with the size of the organ.

  The Cavity of the Body (cavum uteri) is a mere slit, flattened antero-posteriorly. It is triangular in shape, the base being formed by the internal surface of the fundus between the orifices of the uterine tubes, the apex by the internal orifice of the uterus through which the cavity of the body communicates with the canal of the cervix.

  The Canal of the Cervix (canalis cervicis uteri) is somewhat fusiform, flattened from before backward, and broader at the middle than at either extremity. It communicates above through the internal orifice with the cavity of the body, and below through the external orifice with the vaginal cavity. The wall of the canal presents an anterior and a posterior longitudinal ridge, from each of which proceed a number of small oblique columns, the palmate folds, giving the appearance of branches from the stem of a tree; to this arrangement the name arbor vitae uterina is applied. The folds on the two walls are not exactly opposed, but fit between one another so as to close the cervical canal.

 

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Posterior half of uterus and upper part of vagina.

 

  The total length of the uterine cavity from the external orifice to the fundus is about 6.25 cm.

 Ligaments.—The ligaments of the uterus are eight in number: one anterior; one posterior; two lateral or broad; two uterosacral; and two round ligaments.

  The anterior ligament consists of the vesicouterine fold of peritoneum, which is reflected on to the bladder from the front of the uterus, at the junction of the cervix and body.

  The posterior ligament consists of the rectovaginal fold of peritoneum, which is reflected from the back of the posterior fornix of the vagina on to the front of the rectum. It forms the bottom of a deep pouch called the rectouterine excavation, which is bounded in front by the posterior wall of the uterus, the supravaginal cervix, and the posterior fornix of the vagina; behind, by the rectum; and laterally by two crescentic folds of peritoneum which pass backward from the cervix uteri on either side of the rectum to the posterior wall of the pelvis. These folds are named the sacrogenital or rectouterine folds. They contain a considerable amount of fibrous tissue and non-striped muscular fibers which are attached to the front of the sacrum and constitute the uterosacral ligaments.

  The two lateral or broad ligaments (ligamentum latum uteri) pass from the sides of the uterus to the lateral walls of the pelvis. Together with the uterus they form a septum across the female pelvis, dividing that cavity into two portions. In the anterior part is contained the bladder; in the posterior part the rectum, and in certain conditions some coils of the small intestine and a part of the sigmoid colon. Between the two layers of each broad ligament are contained: (1) the uterine tube superiorly; (2) the round ligament of the uterus; (3) the ovary and its ligament; (4) the epoöphoron and paroöphoron; (5) connective tissue; (6) unstriped muscular fibers; and (7) bloodvessels and nerves. The portion of the broad ligament which stretches from the uterine tube to the level of the ovary is known by the name of the mesosalpinx. Between the fimbriated extremity of the tube and the lower attachment of the broad ligament is a concave rounded margin, called the infundibulopelvic ligament.

  The round ligaments (ligamentum teres uteri) are two flattened bands between 10 and 12 cm. in length, situated between the layers of the broad ligament in front of and below the uterine tubes. Commencing on either side at the lateral angle of the uterus, this ligament is directed forward, upward, and lateralward over the external iliac vessels. It then passes through the abdominal inguinal ring and along the inguinal canal to the labium majus, in which it becomes lost. The round ligaments consists principally of muscular tissue, prolonged from the uterus; also of some fibrous and areolar tissue, besides bloodvessels, lymphatics; and nerves, enclosed in a duplicature of peritoneum, which, in the fetus, is prolonged in the form of a tubular process for a short distance into the inguinal canal. This process is called the canal of Nuck. It is generally obliterated in the adult, but sometimes remains pervious even in advanced life. It is analogous to the saccus vaginalis, which precedes the descent of the testis.

  In addition to the ligaments just described, there is a band named the ligamentum transversalis colli (Mackenrodt) on either side of the cervix uteri. It is attached to the side of the cervix uteri and to the vault and lateral fornix of the vagina, and is continuous externally with the fibrous tissue which surrounds the pelvic bloodvessels.

  The form, size, and situation of the uterus vary at different periods of life and under different circumstances.

 

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Sagittal section through the pelvis of a newly born female.

 

  In the fetus the uterus is contained in the abdominal cavity, projecting beyond the superior aperture of the pelvis. The cervix is considerably larger than the body.

  At puberty the uterus is pyriform in shape, and weighs from 14 to 17 gm. It has descended into the pelvis, the fundus being just below the level of the superior aperture of this cavity. The palmate folds are distinct, and extend to the upper part of the cavity of the organ.

  The position of the uterus in the adult is liable to considerable variation, depending chiefly on the condition of the bladder and rectum. When the bladder is empty the entire uterus is directed forward, and is at the same time bent on itself at the junction of the body and cervix, so that the body lies upon the bladder. As the latter fills, the uterus gradually becomes more and more erect, until with a fully distended bladder the fundus may be directed backward toward the sacrum.

  During menstruation the organ is enlarged, more vascular, and its surfaces rounder; the external orifice is rounded, its labia swollen, and the lining membrane of the body thickened, softer, and of a darker color. According to Sir J. Williams, at each recurrence of menstruation, a molecular disintegration of the mucous membrane takes place, which leads to its complete removal, only the bases of the glands imbedded in the muscle being left. At the cessation of menstruation, a fresh mucous membrane is formed by a proliferation of the remaining structures.

  During pregnancy the uterus becomes enormously enlarged, and in the eighth month reaches the epigastric region. The increase in size is partly due to growth of preëxisting muscle, and partly to development of new fibers.

  After parturition the uterus nearly regains its usual size, weighing about 42 gm.; but its cavity is larger than in the virgin state, its vessels are tortuous, and its muscular layers are more defined; the external orifice is more marked, and its edges present one or more fissures.

  In old age the uterus becomes atrophied, and paler and denser in texture; a more distinct constriction separates the body and cervix. The internal orifice is frequently, and the external orifice occasionally, obliterated, while the lips almost entirely disappear.

 

Structure.—The uterus is composed of three coats: an external or serous, a middle or muscular, and an internal or mucous.

  The serous coat (tunica serosa) is derived from the peritoneum; it invests the fundus and the whole of the intestinal surface of the uterus; but covers the vesical surface only as far as the junction of the body and cervix. In the lower fourth of the intestinal surface the peritoneum, though covering the uterus, is not closely connected with it, being separated from it by a layer of loose cellular tissue and some large veins.

  The muscular coat (tunica muscularis) forms the chief bulk of the substance of the uterus. In the virgin it is dense, firm, of a grayish color, and cuts almost like cartilage. It is thick opposite the middle of the body and fundus, and thin at the orifices of the uterine tubes. It consists of bundles of unstriped muscular fibers, disposed in layers, intermixed with areolar tissue, bloodvessels, lymphatic vessels, and nerves. The layers are three in number: external, middle, and internal. The external and middle layers constitute the muscular coat proper, while the inner layer is a greatly hypertrophied muscularis mucosae. During pregnancy the muscular tissue becomes more prominently developed, the fibers being greatly enlarged.

  The external layer, placed beneath the peritoneum, is disposed as a thin plane on the vesical and intestinal surfaces. It consists of fibers which pass transversely across the fundus, and, converging at each lateral angle of the uterus, are continued on to the uterine tube, the round ligament, and the ligament of the ovary: some passing at each side into the broad ligament, and others running backward from the cervix into the sacrouterine ligaments. The middle layer of fibers presents no regularity in its arrangement, being disposed longitudinally, obliquely, and transversely. It contains more bloodvessels than either of the other two layers. The internal or deep layer consists of circular fibers arranged in the form of two hollow cones, the apices of which surround the orifices of the uterine tubes, their bases intermingling with one another on the middle of the body of the uterus. At the internal orifice these circular fibers form a distinct sphincter.

  The mucous membrane (tunica mucosa) is smooth, and closely adherent to the subjacent tissue. It is continuous through the fimbriated extremity of the uterine tubes, with the peritoneum; and, through the external uterine orifice, with the lining of the vagina.

  In the body of the uterus the mucous membrane is smooth, soft, of a pale red color, lined by columnar ciliated epithelium, and presents, when viewed with a lens, the orifices of numerous tubular follicles, arranged perpendicularly to the surface. The structure of the corium differs from that of ordinary mucous membranes, and consists of an embryonic nucleated and highly cellular form of connective tissue in which run numerous large lymphatics. In it are the tube-like uterine glands, lined by ciliated columnar epithelium. They are of small size in the unimpregnated uterus, but shortly after impregnation become enlarged and elongated, presenting a contorted or waved appearance (see page 60).

 

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  In the cervix the mucous membrane is sharply differentiated from that of the uterine cavity. It is thrown into numerous oblique ridges, which diverge from an anterior and posterior longitudinal raphé. In the upper two-thirds of the canal, the mucous membrane is provided with numerous deep glandular follicles, which secrete a clear viscid alkaline mucus; and, in addition, extending through the whole length of the canal is a variable number of little cysts, presumably follicles which have become occluded and distended with retained secretion. They are called the ovula Nabothi. The mucous membrane covering the lower half of the cervical canal presents numerous papillae. The epithelium of the upper two-thirds is cylindrical and ciliated, but below this it loses its cilia, and gradually changes to stratified squamous epithelium close to the external orifice. On the vaginal surface of the cervix the epithelium is similar to that lining the vagina, viz., stratified squamous.

 

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The arteries of the internal organs of generation of the female, seen from behind.

 

Vessels and Nerves.—The arteries of the uterus are the uterine, from the hypogastric; and the ovarian, from the abdominal aorta.  They are remarkable for their tortuous course in the substance of the organ, and for their frequent anastomoses. The termination of the ovarian artery meets that of the uterine artery, and forms an anastomotic trunk from which branches are given off to supply the uterus, their disposition being circular.

 

 

 

 

Theme 2. Structure and topography of vagina, external reproductive organs and urethra. Topography of small pelvis organs on female.

 

The Vagina is a tube of 7-9 cm in length that communicates uterine cavity with external genital organs. Upper portion of vaginae envelopes the uterine neck forming vaginal fornix. Vagina has anterior and posterior walls and opens by orifice into vestibule. Fold of mucous membrane - hymen, closes this orifice in virgins. After defloration remainders of hymen called caruncle. Internal mucous membrane contains columna rugarum that located along the walls of vagine. Middle coat of vagina – muscular, external one – connective tissue.

The vagina extends from the vestibule to the uterus, and is situated behind the bladder and in front of the rectum; it is directed upward and backward, its axis forming with that of the uterus an angle of over 90°, opening forward. Its walls are ordinarily in contact, and the usual shape of its lower part on transverse section is that of an H, the transverse limb being slightly curved forward or backward, while the lateral limbs are somewhat convex toward the median line; its middle part has the appearance of a transverse slit. Its length is 6 to 7.5 cm. along its anterior wall, and 9 cm. along its posterior wall. It is constricted at its commencement, dilated in the middle, and narrowed near its uterine extremity; it surrounds the vaginal portion of the cervix uteri, a short distance from the external orifice of the uterus, its attachment extending higher up on the posterior than on the anterior wall of the uterus. To the recess behind the cervix the term posterior fornix is applied, while the smaller recesses in front and at the sides are called the anterior and lateral fornices.

Relations.—The anterior surface of the vagina is in relation with the fundus of the bladder, and with the urethra. Its posterior surface is separated from the rectum by the rectouterine excavation in its upper fourth, and by the rectovesical fascia in its middle two-fourths; the lower fourth is separated from the anal canal by the perineal body. Its sides are enclosed between the Levatores ani muscles. As the terminal portions of the ureters pass forward and medialward to reach the fundus of the bladder, they run close to the lateral fornices of the vagina, and as they enter the bladder are slightly in front of the anterior fornix.

 

VIDEO

 

Structure.—The vagina consists of an internal mucous lining and a muscular coat separated by a layer of erectile tissue.

  The mucous membrane (tunica mucosa) is continuous above with that lining the uterus. Its inner surface presents two longitudinal ridges, one on its anterior and one on its posterior wall. These ridges are called the columns of the vagina and from them numerous transverse ridges or rugae extend outward on either side. These rugae are divided by furrows of variable depth, giving to the mucous membrane the appearance of being studded over with conical projections or papillae; they are most numerous near the orifice of the vagina, especially before parturition. The epithelium covering the mucous membrane is of the stratified squamous variety. The submucous tissue is very loose, and contains numerous large veins which by their anastomoses form a plexus, together with smooth muscular fibers derived from the muscular coat; it is regarded by Gussenbauer as an erectile tissue. It contains a number of mucous crypts, but no true glands.

  The muscular coat (tunica muscularis) consists of two layers: an external longitudinal, which is by far the stronger, and an internal circular layer. The longitudinal fibers are continuous with the superficial muscular fibers of the uterus. The strongest fasciculi are those attached to the rectovesical fascia on either side. The two layers are not distinctly separable from each other, but are connected by oblique decussating fasciculi, which pass from the one layer to the other. In addition to this, the vagina at its lower end is surrounded by a band of striped muscular fibers, the Bulbocavernosus (see page 430).

  External to the muscular coat is a layer of connective tissue, containing a large plexus of bloodvessels.

  The erectile tissue consists of a layer of loose connective tissue, situated between the mucous membrane and the muscular coat; imbedded in it is a plexus of large veins, and numerous bundles of unstriped muscular fibers, derived from the circular muscular layer. The arrangement of the veins is similar to that found in other erectile tissues.

 

Female  pudendal  area

The major pudenda labia limit a pudenda rima. Right and left major pudenda labia communicate by each other by the by means of anterior labial comissura and posterior comissura.

Minor pudendal labia are the skin folds without adipose tissue, they lie medially from major pudenda labia. Anterior margin of minor pudendal labia bifurcates and forms prerutium of clitoris and frenulum of clitoris.

The Clitoris is by length 2-З cm, is analogue of cavernous bodies of penis and consists of head, body and legs of clitoris. The legs of clitoris attach to inferior rami of pubic bone.

The Vestibule vaginae are a fissure between minor pudendal labia. External urethral ostium, vaginal foramen and ducts of minor and major (Bartolini) vestibular glands open here. Bulbus vestibuli vagina consists of cavernous tissue, which is situated on sides from inferior vaginal end (analogue of sponges body of penis).

 

 

Theme 3. Perineal muscles and fasciae on male and female. Radiograph anatomy of urinary and reproductive organs

 

 

The PERINEUM in narrow aspect is the soft tissues situated between anus and external genital. In wide understanding a perineum is a complex of soft tissues, which close pelvic outlet.

Perineum is diamond-shaped area, which is limited by coccyx behind, by inferior margin of pubic symphysis anteriorly and by sciatic tuber - laterally. Perineum subdivides by line between right and left sciatic tubers into anterior urogenital triangle and posterior anal triangle. Anterior triangle lies in oblique frontal plane and urethra passes through it in males, and in female - a vagina and urethra. Posterior triangle lies in horizontal plane, is called by pelvic or anal triangle and terminal portion of rectum passes through it.

The perineal muscles subdivide into superficial and deep groups.

Superficial muscles of urogenital triangle:

ü superficial transversal perineal muscle, which fixes a perineum;

ü bulbo-spongious muscle, which compresses an entrance into vagina into female, and into males presses out sperm or urine;

ü ischiocavernous muscle, which assists erections of penis or clitoris.

Superficial muscles of pelvic triangle

ü external muscle-sphincter ani, which consists of striped fibres (voluntary).

Deep muscles of perineum form urogenital and pelvic diaphragm.

Deep muscles of urogenital triangle:

ü deep transversal perineal muscle, which fixes a perineum;

ü sphincter urethrae formed by circular stripped (voluntary) fibres;

Deep muscles of pelvic triangle

ü levator ani muscle;

ü coccygeal muscle.

Fasciae of pelvic area:

Pelvic fascia is continuation of iliac fascia and has a parietal sheet and visceral sheet. Parietal pelvic fascia covers levator ani muscle and internal obturatorius muscle. Visceral pelvic fascia invests the rectum and other organs. Part of parietal pelvic fasciae, which covers a levator ani muscle above is called superior fascia of pelvic diaphragm. Inferior fascia of pelvic diaphragm covers the levator ani muscle below. Membranous layer limits below external sphincter ani and ischioanal fossa.

Pelvic diaphragm = Deep muscles + Superior fascia + Inferior fascia

The ischioanal [ischiorectal] fossa around the wall of the anal canal are large fascia-lined, wedge-shaped space between the skin of anal region and the pelvic diaphragm. It contains adiposal body and pudendal canal  (Alcock`s) with nerves and vessels.

The urogenital triangle

Superior fascia of urogenital diaphragm is continuation of pelvic fascia and covers from above deep muscles.

A thin and tough sheet, the perineal membrane ( inferior fascia of urogenital diaphragm) stretches between the two sides of the pubic arch and covers below the anterior part of the pelvic outlet. The perineal membrane located between the superficial and deep muscles. The perineal body is a fibromuscular mass located in the midpoint between the anal canal and perineal membrane.

Urogenital diaphragm = Deep muscles + Superior fascia + Inferior fascia

Superficial perineal fascia (investing fascia) intimately invests superficial muscles of urogenital triangle. Anteriorly it is fused to the suspensory ligament of the penis.

Subcutaneous membranous layer (stratum) passes superior to the labia majora (in female) and in males continuous with the dartos  fascia in scrotum.

Superficial perineal pouch (compartment) is the potential space between superficial investing fascia and perineal membrane. In males superficial perineal pouch contains: root of the penis with associated superficial muscles, pudendal vessels and nerves. In females superficial perineal pouch contains: crura of the clitoris and bulb of vestibule, associated with them superficial muscles, pudendal vessels and nerves, greater vestibular glands.

Deep perineal pouch (space) is not an enclosed compartment; it is open superiorly. This pouch is bounded below by the perineal membrane.  In males deep perineal pouch contains: membranous part of urethra, external urethral sphincter muscle, bulbourethral glands, deep transverse perineal muscles, related nerves and vessels. In females the deep perineal pouch contains the: proximal part of urethra, external urethral sphincter muscle, deep transverse perineal muscles, related nerves and vessels.

The perineum corresponds to the outlet of the pelvis. Its deep boundaries are—in front, the pubic arch and the arcuate ligament of the pubis; behind, the tip of the coccyx; and on either side the inferior rami of the pubis and ischium, and the sacrotuberous ligament. The space is somewhat lozenge-shaped and is limited on the surface of the body by the scrotum in front, by the buttocks behind, and laterally by the medial side of the thigh. A line drawn transversely across in front of the ischial tuberosities divides the space into two portions. The posterior contains the termination of the anal canal and is known as the anal region; the anterior, which contains the external urogenital organs, is termed the urogenital region.

  The muscles of the perineum may therefore be divided into two groups:

1. Those of the anal region.

2. Those of the urogenital region: A, In the male; B, In the female.

 

The Superficial Fascia.—The superficial fascia is very thick, areolar in texture, and contains much fat in its meshes. On either side a pad of fatty tissue extends deeply between the Levator ani and Obturator internus into a space known as the ischiorectal fossa.

 

The Deep Fascia.—The deep fascia forms the lining of the ischiorectal fossa; it comprises the anal fascia, and the portion of obturator fascia below the origin of Levator ani.

 

Ischiorectal Fossa (fossa ischiorectalis) is somewhat prismatic in shape, with its base directed to the surface of the perineum, and its apex at the line of meeting of the obturator and anal fasciae. It is bounded medially by the Sphincter ani externus and the anal fascia; laterally, by the tuberosity of the ischium and the obturator fascia; anteriorly, by the fascia of Colles covering the Transversus perinaei superficialis, and by the inferior fascia of the urogenital diaphragm; posteriorly, by the Glutaeus maximus and the sacrotuberous ligament. Crossing the space transversely are the inferior hemorrhoidal vessels and nerves; at the back part are the perineal and perforating cutaneous branches of the pudendal plexus; while from the forepart the posterior scrotal (or labial) vessels and nerves emerge. The internal pudendal vessels and pudendal nerve lie in Alcock’s canal on the lateral wall. The fossa is filled with fatty tissue across which numerous fibrous bands extend from side to side.

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The perineum. The integument and superficial layer of superficial fascia reflected.

  The Sphincter ani externus (External sphincter ani) is a flat plane of muscular fibers, elliptical in shape and intimately adherent to the integument surrounding the margin of the anus. It measures about 8 to 10 cm. in length, from its anterior to its posterior extremity, and is about 2.5 cm. broad opposite the anus. It consists of two strata, superficial and deep. The superficial, constituting the main portion of the muscle, arises from a narrow tendinous band, the anococcygeal raphé, which stretches from the tip of the coccyx to the posterior margin of the anus; it forms two flattened planes of muscular tissue, which encircle the anus and meet in front to be inserted into the central tendinous point of the perineum, joining with the Transversus perinaei superficialis, the Levator ani, and the Bulbocavernosus. The deeper portion forms a complete sphincter to the anal canal. Its fibers surround the canal, closely applied to the Sphincter ani internus, and in front blend with the other muscles at the central point of the perineum. In a considerable proportion of cases the fibers decussate in front of the anus, and are continuous with the Transversi perinaei superficiales. Posteriorly, they are not attached to the coccyx, but are continuous with those of the opposite side behind the anal canal. The upper edge of the muscle is ill-defined, since fibers are given off from it to join the Levator ani.

 

Nerve Supply.—A branch from the fourth sacral and twigs from the inferior hemorrhoidal branch of the pudendal supply the muscle.

 

Actions.—The action of this muscle is peculiar. (1) It is, like other muscles, always in a state of tonic contraction, and having no antagonistic muscle it keeps the anal canal and orifice closed. (2) It can be put into a condition of greater contraction under the influence of the will, so as more firmly to occlude the anal aperture, in expiratory efforts unconnected with defecation. (3) Taking its fixed point at the coccyx, it helps to fix the central point of the perineum, so that the Bulbocavernosus may act from this fixed point.

  The Sphincter ani internus (Internal sphincter ani) is a muscular ring which surrounds about 2.5 cm. of the anal canal; its inferior border is in contact with, but quite separate from, the Sphincter ani externus. It is about 5 mm. thick, and is formed by an aggregation of the involuntary circular fibers of the intestine. Its lower border is about 6 mm. from the orifice of the anus.

 

Actions.—Its action is entirely involuntary. It helps the Sphincter ani externus to occlude the anal aperture and aids in the expulsion of the feces.

 

2. A. The Muscles of the Urogenital Region in the Male   

Transversus perinaei superficialis.

Ischiocavernosus.

Bulbocavernosus.

Transversus perinaei profundus.

Sphincter urethrae membranaceae.

Superficial Fascia.The superficial fascia of this region consists of two layers, superficial and deep.

  The superficial layer is thick, loose, areolar in texture, and contains in its meshes much adipose tissue, the amount of which varies in different subjects. In front, it is continuous with the dartos tunic of the scrotum; behind, with the subcutaneous areolar tissue surrounding the anus; and, on either side, with the same fascia on the inner sides of the thighs. In the middle line, it is adherent to the skin on the raphé and to the deep layer of the superficial fascia.

  The deep layer of superficial fascia (fascia of Colles) is thin, aponeurotic in structure, and of considerable strength, serving to bind down the muscles of the root of the penis. It is continuous, in front, with the dartos tunic, the deep fascia of the penis, the fascia of the spermatic cord, and Scarpa’s fascia upon the anterior wall of the abdomen; on either side it is firmly attached to the margins of the rami of the pubis and ischium, lateral to the crus penis and as far back as the tuberosity of the ischium; posteriorly, it curves around the Transversi perinaei superficiales to join the lower margin of the inferior fascia of the urogenital diaphragm. In the middle line, it is connected with the superficial fascia and with the median septum of the Bulbocavernosus. This fascia not only covers the muscles in this region, but at its back part sends upward a vertical septum from its deep surface, which separates the posterior portion of the subjacent space into two.

 

The Central Tendinous Point of the Perineum.This is a fibrous point in the middle line of the perineum, between the urethra and anus, and about 1.25 cm. in front of the latter. At this point six muscles converge and are attached: viz., the Sphincter ani externus, the Bulbocavernosus, the two Transversi perinaei superficiales, and the anterior fibers of the Levatores ani.

 

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Muscles of male perineum.

 

  The Transversus perinaei superficialis (Transversus perinaei; Superficial transverse perineal muscle) is a narrow muscular slip, which passes more or less transversely across the perineal space in front of the anus. It arises by tendinous fibers from the inner and forepart of the tuberosity of the ischium, and, running medialward, is inserted into the central tendinous point of the perineum, joining in this situation with the muscle of the opposite side, with the Sphincter ani externus behind, and with the Bulbocavernosus in front. In some cases, the fibers of the deeper layer of the Sphincter ani externus decussate in front of the anus and are continued into this muscle. Occasionally it gives off fibers, which join with the Bulbocavernosus of the same side.

  Variations are numerous. It may be absent or double, or insert into Bulbocavernosus or External sphincter.

 

Actions.The simultaneous contraction of the two muscles serves to fix the central tendinous point of the perineum.

  The Bulbocavernosus (Ejaculator urinae; Accelerator urinae) is placed in the middle line of the perineum, in front of the anus. It consists of two symmetrical parts, united along the median line by a tendinous raphé. It arises from the central tendinous point of the perineum and from the median raphé in front. Its fibers diverge like the barbs of a quill-pen; the most posterior form a thin layer, which is lost on the inferior fascia of the urogenital diaphragm; the middle fibers encircle the bulb and adjacent parts, of the corpus cavernosum urethrae, and join with the fibers of the opposite side, on the upper part of the corpus cavernosum urethrae, in a strong aponeurosis; the anterior fibers, spread out over the side of the corpus cavernosum penis, to be inserted partly into that body, anterior to the Ischiocavernosus, occasionally extending to the pubis, and partly ending in a tendinous expansion which covers the dorsal vessels of the penis. The latter fibers are best seen by dividing the muscle longitudinally, and reflecting it from the surface of the corpus cavernosum urethrae.

 

Actions.This muscle serves to empty the canal of the urethra, after the bladder has expelled its contents; during the greater part of the act of micturition its fibers are relaxed, and it only comes into action at the end of the process. The middle fibers are supposed by Krause to assist in the erection of the corpus cavernosum urethrae, by compressing the erectile tissue of the bulb. The anterior fibers, according to Tyrrel, also contribute to the erection of the penis by compressing the deep dorsal vein of the penis as they are inserted into, and continuous with, the fascia of the penis.

  The Ischiocavernosus (Erector penis) covers the crus penis. It is an elongated muscle, broader in the middle than at either end, and situated on the lateral boundary of the perineum. It arises by tendinous and fleshy fibers from the inner surface of the tuberosity of the ischium, behind the crus penis; and from the rami of the pubis and ischium on either side of the crus. From these points fleshy fibers succeed, and end in an aponeurosis which is inserted into the sides and under surface of the crus penis.

 

Action.The Ischiocavernosus compresses the crus penis, and retards the return of the blood through the veins, and thus serves to maintain the organ erect.

  Between the muscles just examined a triangular space exists, bounded medially by the Bulbocavernosus, laterally by the Ischiocavernosus, and behind by the Transversus perinaei superficialis; the floor is formed by the inferior fascia of the urogenital diaphragm. Running from behind forward in the space are the posterior scrotal vessels and nerves, and the perineal branch of the posterior femoral cutaneous nerve; the transverse perineal artery courses along its posterior boundary on the Transversus perinaei superficialis.

 

The Deep Fascia.The deep fascia of the urogenital region forms an investment for the Transversus perinaei profundus and the Sphincter urethrae membranaceae, but within it lie also the deep vessels and nerves of this part, the whole forming a transverse septum which is known as the urogenital diaphragm. From its shape it is usually termed the triangular ligament, and is stretched almost horizontally across the pubic arch, so as to close in the front part of the outlet of the pelvis. It consists of two dense membranous laminae, which are united along their posterior borders, but are separated in front by intervening structures. The superficial of these two layers, the inferior fascia of the urogenital diaphragm, is triangular in shape, and about 4 cm. in depth. Its apex is directed forward, and is separated from the arcuate pubic ligament by an oval opening for the transmission of the deep dorsal vein of the penis. Its lateral margins are attached on either side to the inferior rami of the pubis and ischium, above the crus penis. Its base is directed toward the rectum, and connected to the central tendinous point of the perineum. It is continuous with the deep layer of the superficial fascia behind the Transversus perinaei superficialis, and with the inferior layer of the diaphragmatic part of the pelvic fascia. It is perforated, about 2.5 cm. below the symphysis pubis, by the urethra, the aperture for which is circular and about 6 mm. in diameter by the arteries to the bulb and the ducts of the bulbourethral glands close to the urethral orifice; by the deep arteries of the penis, one on either side close to the pubic arch and about halfway along the attached margin of the fascia; by the dorsal arteries and nerves of the penis near the apex of the fascia. Its base is also perforated by the perineal vessels and nerves, while between its apex and the arcuate pubic ligament the deep dorsal vein of the penis passes upward into the pelvis.

  If the inferior fascia of the urogenital diaphragm be detached on either side, the following structures will be seen between it and the superior fascia: the deep dorsal vein of the penis; the membranous portion of the urethra; the Transversus perinaei profundus and Sphincter urethrae membranaceae muscles; the bulbourethral glands and their ducts; the pudendal vessels and dorsal nerves of the penis; the arteries and nerves of the urethral bulb, and a plexus of veins.

 

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Coronal section of anterior part of pelvis, through the pubic arch. Seen from in front. (Diagrammatic.)

 

  The superior fascia of the urogenital diaphragm is continuous with the obturator fascia and stretches across the pubic arch. If the obturator fascia be traced medially after leaving the Obturator internus muscle, it will be found attached by some of its deeper or anterior fibers to the inner margin of the pubic arch, while its superficial or posterior fibers pass over this attachment to become continuous with the superior fascia of the urogenital diaphragm. Behind, this layer of the fascia is continuous with the inferior fascia and with the fascia of Colles; in front it is continuous with the fascial sheath of the prostate, and is fused with the inferior fascia to form the transverse ligament of the pelvis.

  The Transversus perinaei profundus arises from the inferior rami of the ischium and runs to the median line, where it interlaces in a tendinous raphé with its fellow of the opposite side. It lies in the same plane as the Sphincter urethrae membranaceae; formerly the two muscles were described together as the Constrictor urethrae.

  The Sphincter urethrae membranaceae surrounds the whole length of the membranous portion of the urethra, and is enclosed in the fasciae of the urogenital diaphragm. Its external fibers arise from the junction of the inferior rami of the pubis and ischium to the extent of 1.25 to 2 cm., and from the neighboring fasciae. They arch across the front of the urethra and bulbourethral glands, pass around the urethra, and behind it unite with the muscle of the opposite side, by means of a tendinous raphé. Its innermost fibers form a continuous circular investment for the membranous urethra.

 

Nerve Supply.The perineal branch of the pudendal nerve supplies this group of muscles.

 Actions.The muscles of both sides act together as a sphincter, compressing the membranous portion of the urethra. During the transmission of fluids they, like the Bulbocavernosus, are relaxed, and only come into action at the end of the process to eject the last drops of the fluid.

 

2. B. The Muscles of the Urogenital Region in the Female  

Transversus perinaei superficialis.

Ischiocavernosus.

Bulbocavernosus.

Transversus perinaei profundus.

Sphincter urethrae membranaceae.

 

  The Transversus perinaei superficialis (Transversus perinaei; Superficial transverse perineal muscle) in the female is a narrow muscular slip, which arises by a small tendon from the inner and forepart of the tuberosity of the ischium, and is inserted into the central tendinous point of the perineum, joining in this situation with the muscle of the opposite side, the Sphincter ani externus behind, and the Bulbocavernosus in front.

 

Action.The simultaneous contraction of the two muscles serves to fix the central tendinous point of the perineum.

  The Bulbocavernosus (Sphincter vaginae) surrounds the orifice of the vagina. It covers the lateral parts of the vestibular bulbs, and is attached posteriorly to the central tendinous point of the perineum, where it blends with the Sphincter ani externus. Its fibers pass forward on either side of the vagina to be inserted into the corpora cavernosa clitoridis, a fasciculus crossing over the body of the organ so as to compress the deep dorsal vein.

 

Actions.The Bulbocavernosus diminishes the orifice of the vagina. The anterior fibers contribute to the erection of the clitoris, as they are inserted into and are continuous with the fascia of the clitoris, compressing the deep dorsal vein during the contraction of the muscle.

  The Ischiocavernosus (Erector clitoridis) is smaller than the corresponding muscle in the male. It covers the unattached surface of the crus clitoridis. It is an elongated muscle, broader at the middle than at either end, and situated on the side of the lateral boundary of the perineum. It arises by tendinous and fleshy fibers from the inner surface of the tuberosity of the ischium, behind the crus clitoridis; from the surface of the crus; and from the adjacent portion of the ramus of the ischium. From these points fleshy fibers succeed, and end in an aponeurosis, which is inserted into the sides and under surface of the crus clitoridis.

 

Actions.The Ischiocavernosus compresses the crus clitoridis and retards the return of blood through the veins, and thus serves to maintain the organ erect.

  The fascia of the urogenital diaphragm in the female is not so strong as in the male. It is attached to the public arch, its apex being connected with the arcuate pubic ligament. It is divided in the middle line by the aperture of the vagina, with the external coat of which it becomes blended, and in front of this is perforated by the urethra. Its posterior border is continuous, as in the male, with the deep layer of the superficial fascia around the Transversus perinaei superficialis.

  Like the corresponding fascia in the male, it consists of two layers, between which are to be found the following structures: the deep dorsal vein of the clitoris, a portion of the urethra and the Constrictor urethra muscle, the larger vestibular glands and their ducts; the internal pudendal vessels and the dorsal nerves of the clitoris; the arteries and nerves of the bulbi vestibuli, and a plexus of veins.

  

 

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Muscles of the female perineum.

 

The Transversus perinei profundus arises from the inferior rami of the ischium and runs across to the side of the vagina. The Sphincter urethrae membranaceae (Constrictor urethrae), like the corresponding muscle on the male, consists of external and internal fibers. The external fibers arise on either side from the margin of the inferior ramus of the pubis. They are directed across the pubic arch in front of the urethra, and pass around it to blend with the muscular fibers of the opposite side, between the urethra and vagina. The innermost fibers encircle the lower end of the urethra.

 

 

 

Prepared by

A.V.Miz