In considering the anatomy of the pelvic organs, only certain points will be mentioned that are particularly related to intra-pelvic technic.

First we must visualize a pelvic cavity entirely filled with viscera. There is no unfilled space. (Fig. 4.) Everywhere each viscus touches and is touched by others. It is only by this vision that we get a true understanding of the etiology and pathology of the conditions which we expect to correct. Nor must we consider only the internal generative organs. Besides these there are the bladder, the urethra, the ureters, the pelvic colon, the rectum, the coils of small intestines, peritoneum and connective tissue. These with their positional relationship to each other as well as their relationship through blood, nerve and lymph supply must be understood.

The uterus (Fig. 1) will be disposed of without a discussion of its ultimate structure as this is capably dealt with in the usual textbooks on gynecology. For our purposes its normal size, position and mobility are of more immediate importance. In fact the physician who has not by experience become familiar with these cannot hope to attain to the fullest success in practice.

The virgin adult uterus is slightly less than three inches long, slightly less than two inches wide and about one inch thick. After childbirth it remains somewhat larger than before and after the menopause it again shrinks. When palpated through the abdominal walls it seems larger than the dimensions given, owing to the thickness of the tissues through which it is felt. Only by familiarity with its normal size can the small infantile or the atropic, or the enlarged, congested or subinvoluted uterus be recognized.

The fundus of the uterus, when the bladder and rectum are both empty, rises to or slightly above the brim of the pelvis. It is directed forward and slightly, upward. It is approximately in the median line, (slightly to the left according to some authorities) and rests forward upon the bladder. The long axis of the body of the uterus is nearly horizontal in the erect position, almost perpendicular in the dorsal position and forms a slight angle with the cervical canal. This position may be considerably modified by the distension of the bladder or rectum. As the bladder fills the uterus becomes more and more perpendicular, (in the erect posture) and with the bladder fully distended the fundus may point upward or even slightly backward toward the sacrum.

Distension of the rectum affects the position of the uterus less markedly, but to some extent. It may press the uterus forward and may render more acute the angle between the body and cervix.

Fig. 2. Uterine Ligaments, Showing Them All on Same Plane.
(Gilliam, A Text Book of Practical Gynecology.)

The cervix is normally found about midway the ischial spines, and should point backward and slightly downward. Its direction is also affected, to some degree, by the distension of the bladder and rectum. As the former fills, the cervix points more and more downward, and the same is true as the latter fills. This is because the uterus tilts about a transverse axis running approximately through the cervicocorporeal junction. Pressure applied to the anterior surface of the fundus has the same effect on the position of the cervix as pressure applied to the posterior surface of the cervix.

The uterus has four pairs of ligaments. (Fig. 2). These limit extreme motion of the uterus but do not contribute, directly, a great deal to its support. The chief means of its support is the pelvic floor. There are two vesico-uterine ligaments anteriorly, two sacro-uterine ligaments posteriorly, and a broad and a round ligament laterally.

The vesico-uterine ligaments are formed of two folds of peritoneum that are reflected over the pelvic connective tissue lying between the bladder and the uterus.

The sacro-uterine ligaments are formed of unstriped muscular fibers continuous with those of the uterus, with fibrous and loose connective tissue, all of which are covered by peritoneum. They are attached to the anterior surface of the second and third bones of the sacrum. From here they run downward and forward to the uterus, one on either side, and are attached at the level of the internal os. Occasionally similar secondary bonds pass downward from the fifth lumbar vertebra. These ligaments with the anterior vaginal walls are said to form an elastic beam by which the uterus is suspended. These ligaments in their normal condition prevent the uterus from being dragged beyond the vaginal entrance.

The broad ligaments are composed of loose connective tissue and unstriped muscle fibers, covering which is peritoneum. They are attached by their inner margins to the sides of the uterus and at their outer margins o the sides of the pelvic wall, following a line beginning midway between the ilio-pectineal eminence and the sacro-iliac articulation, and running downward and backward to the level of the spine of the ischium between the great sacro-sciatic notch and the obturator foramen. At their outer margins these ligaments are nearly vertical (in the erect position), while at their inner margins they are nearly horizontal forming shelf upon which rest the intestines. These ligaments, in a small degree, limit the lateral motion of the uterus, and if the sacro-uterine ligaments have for any reason lost their tone, they assist in preventing total prolapse.

Between the peritoneal layers of the broad ligaments, and transversing the connective tissue of which they are largely composed, are the ovarian and uterine blood vessels, lymphatics and nerves. There are also the uterine tubes, the parovarium, the round ligament and in its lower part near the cervix, the ureter. The ovary is rather on the posterior or upper layer of the broad ligament.

The muscle fibers in the broad ligament are of the unstriped variety, a continuation of the outer layer of the uterine muscle, and form a flat layer between the uterus, ovaries and tubes.

The round ligaments are composed of unstriped muscle fibers from the uterus, arising from its superior angles. They pass forward, upward and outward, between the layers of the broad ligament, in front of and below the uterine tube. They enter the internal abdominal ring, pass through the inguinal canal and are inserted into the subcutaneous tissues of the labia majoria. They are supplied by the genital branch of the genito-crural nerve and are capable of electric stimulation. They are pierced through their center by a branch of the deep epigastric artery. They are from four to five inches long and contracting together tend to pull the fundus of the uterus forward and perhaps prevent retroversion in coughing, lifting or straining.

Fig 3. Surface Location of Ovaries.

The, ovaries are two flattened, elongated, oval shaped -bodies about one and one-half inches long, three-fourths inches wide and about one-third inch thick. They are placed with their long-axes almost vertical. Their lower extremities are attached to the uterus by the ovarian ligament, their upper extremities to the fimbriated end of the uterine tube. By their anterior margins, which look forward and outward, they are attached to the broad ligament. The free margin looks inward and backward toward the rectum. The ovaries are peculiar in that they are in reality within the peritoneal cavity. The peritoneum forming the broad ligament ceases at the attached edge of the ovary. Each ovary lies in a shallow depression on the lateral wall of the pelvis called the ovarian fossa. This fossa is bounded in front by the hypogastric artery, behind by the ureter and above by the external ilias vessels. It is slightly to the side of and in front of the rectum. The position of the ovary is variable. It perhaps never exactly regains the position from which it is displaced by the first pregnancy. It is affected by posture, the degree of distension of the bladder or rectum and by the position of the uterus.  Its tendency, unless restrained by adhesions is to backward and downward displacement into the recto-uterine excavation.  In its varied positions the uterine tube forms a loop  around it, the inner half of the tube ascending obliquely over It, the outer half with the dilated extremity, descending and bulging out behind it, from which the fimbriae pass to grasp it.

Within the pelvis the bladder being empty, a line connecting the two ovaries would pass posterior to the body of the uterus. On the surface of the body the ovaries lie about one and one-half inches below a point about two inches toward the median line from the anterior superior spinous processes of the ilium. (Fig. 3.)

The uterine tubes begin at the superior angles of the uterus and pass outward to the side of the pelvis. They are situated in the upper margin of the broad ligament, and are from three to five inches long. Their inner third is constricted and called the isthmus, the outer portion, the infundibulum or fimbriated extremity, and the intermediate dilated portion which curves over the ovary is the ampulla. They pursue a tortuous course, and are directed laterally to the uterine extremity of the ovary; they then ascend along the anterior margin of the ovary to the tubal extremity. Arching over this they turn downward and terminate in twelve to fifteen fringe-like processes, the fimbriated extremity that partially surrounds the ovary, embracing its free -border and inner surface.

The vagina is a musculo-membranous canal leading from the vulva to the uterus. Its anterior wall which is in relation with the urethra and bladder is about two and one-half inches long. Its posterior wall about three and one-half inches long is in relation with the perineal body at its lower fourth. Its middle two-fourths are in close relationship with the anterior rectal wall, being separated from it by a small amount of loose connective tissue with blood vessels and lymphatics. Its upper fourth is in contact with the recto-uterine excavation, and is separated from the peritoneum by a thin layer of tissue.

The walls of the vagina are in contact, a transverse section showing the canal to have the general shape of the letter H with a long transverse bar. Its axis forms nearly a right angle with the axis of the uterus when that organ is in normal position. The posterior wall extends higher up on the cervix of the uterus than does the anterior. The junction of the anterior and posterior walls of the vagina with the cervix forms the anterior, and posterior fornices, respectively.

The mucous membrane of the vagina more nearly resembles skin than ordinary mucous membrane, being a stratified pavement epithelium resting upon dermal papillae.

The bladder is in relation posteriorly with the upper part of the vagina and the uterus.  It is rather closely connected with the upper portion of the vagina and the front of the cervix by areolar tissue.  Its degree of fullness affects to some degree the position of the uterus.

The urethra is embedded in the anterior vaginal wall, with which its general direction coincides. It is about one and one-half to one and three-fourths inches long and about one-fourth inch in diameter. It is capable of dilation to a diameter of almost an inch.
 
The ureters enter the pelvis about an inch and a quarter to an inch and a half from the median line. They follow the curve of the pelvis, first downward, backward and outward; they then pass forward and toward the median line about three-fourths of an inch, lateral to the cervix of the uterus. Coursing through the upper part of the vaginal walls they reach the fundus of the bladder. They pass obliquely through the walls of the contracted bladder for a distance slightly less than one inch. They are about one inch apart, this distance increasing with distension of the bladder.

The pelvic colon begins at the superior strait of the pelvis and at about the middle of the third sacral vertebra becomes continuous with the rectum. Its average length is about sixteen inches, though it tray vary from 4.8 inches to 33.6 inches and even in one case to 41.5 inches, (Pennington). It is completely surrounded by peritoneum having a mesentery which is longer at its middle portion than at the ends, thus allowing this portion considerable range of motion. It is in relation anteriorly with the uterus and broad ligaments. Dr. M. E. Clark says it rests upon the fundus of the uterus. It often lies in the recto-uterine excavation, covered by coils of small intestines.

Fig. 4. The Uterus and Its Relation to the Bladder, Rectum and Small Intestines.

The rectum extends from the middle of the third sacral  vertebrae to a little beyond the tip of the coccyx. It is about five inches in length, and follows the curve of the sacrum. The lower portion of the rectum is dilated, forming the ampulla.

Anteriorly and laterally the rectum is covered (by peritoneum for its upper two-thirds, but lower down only its anterior surface is so covered. The rectum is in relation anteriorly with the uterus, some coils of small intestines and frequently the pelvic colon unless a retro-displacement, of the uterus be present. Lateral to the rectum are the ovaries, the fimbriated extremities of the uterine tubes and the ureters.

Coils of the small intestines can often be found in the recto-uterine excavation, unless this is already filled by the pelvic colon or a retro-displaced uterus. The small intestines are also in contact with the posterior or upper layer of the broad ligament and the upper surface of the uterus, unless as sometimes happens they are crowded out by the pelvic colon.  (Fig. 4.)

The parovarium is the remains of the Wolffian body and the Wolffian duct. It is between the ovary and the uterine tube and is sometimes the source of origin of cysts.

Lying upon the pelvic fascia which covers the muscles forming the floor of the pelvis, is a variable amount of loose connective tissue. This serves as a sort of cushion for the viscera and a support for their blood vessels, nerves and lymphatics. This tissue is most abundant at the base of the broad ligaments, the sides of the upper portion of the vagina and about the cervix. It constitutes a large part of the ligaments of the uterus and in it ramify the uterine, ovarian, and tubal arteries and veins. In any condition causing pelvic congestion these vessels become enlarged. This connective tissue is frequently the seat of inflammatory effusions and exudates which may become organized and form cicatricial bands.

The peritoneum lining the pelvic cavity is a continuation of that, lining the abdominal cavity. Posteriorly it passes downward covering the pyriformis muscle and the sacral nerves, and embraces the upper third of the rectum. Passing on down it covers the anterior surface of the middle third of the rectum forming, as it passes from the rectum to the pelvic floor and from there to the upper portion of the vagina and on to the uterus, the recto-uterine excavation. It covers the uterus posteriorly and anteriorly as far down as the cervico-uterine angle. It passes on to the bladder forming the vesicouterine excavation, covering its anterior and posterior surfaces from which it is reflected to the anterior abdominal walls. The folds of peritoneum passing over the uterus posteriorly and anteriorly are reflected over the uterine tubes and form the posterior and anterior layers of the broad ligaments. Laterally the peritoneum forming the broad ligaments passes on to the sides of the pelvis.

Fig. 5. THE NERVES OF THE PELVIC ORGANS OF WOMAN.
(FRANKENHAUSER.)
1. Nerves to fundus of uterus. 2. Right Fallopian tube. 3. Right round ligament. 4. Nerves to Fallopian tube. 5. Communication between uterine and ovarian nerves. 6. Ovarian plexus. 7. Ovarian vein. 8. Nerve passing to ovarian plexus. 9. Fimbriated extremity of Fallopian tube. 10. Reflected peritonum_ 11. Uterine nerves. 12. Superior hypogastric plexus. 13. Branches from hypogastric plexus to uterus. 14. Inferior hypogastric plexus. 15. Vesical nerves. 16. Communicating branches to vesical plexus. 17. Cervical ganglion. 18. Branches from hypogastric plexus to cervical ganglion. 19. First sacral nerve. 20. Branches passing to bladder. 21. Branches passing between bladder and rectum.  22. Communicating branches from second sacral to cervical ganglion. 23. Branch from third sacral nerve to cervical ganglion. 24. Second sacral nerve. 25. Branches from third sacral nerve to vagina and bladder. 26. Branches passing from fourth sacral to cervical ganglion (Garrigues).

Within the pelvic cavity peritoneal surfaces are continually in contact. When inflammation occurs, as it frequently does, the inflamed surfaces readily become adherent and form adhesions between the uterus and the surrounding viscera. Such adhesions are common sources of displacement or other pathological conditions.

The blood supply of the internal generative organs is so closely related that it is best considered collectively. It comes chiefly from the uterine and vaginal branches of the hypogastric and from the ovarian branch of the abdominal aorta. To a more limited extent the vesical, internal pudendal and middle hemorrhoidal branches of the hypogastric also supply these organs.  A remarkable thing about these arteries, particularly the uterine and ovarian, is their tortuous course and the fact that these two form one large continuous anastomotic trunk. So intimate is their connection that during pregnancy, it is claimed by some, the ovarian artery furnishes the principal blood supply to the uterus. They lie for the most part in the connective tissue between the layers of the broad ligament.

The venous system of the internal generative organs, in reality, forms one great pelvic plexus embedded in the connective tissue of the pelvis. Various parts of this plexus are named from their connection with some particular organ or from some other peculiarity.

The veins from the uterus arise from a network in its muscular substance from which they pass into a dense plexus at the sides of the organ. From this, the uterine plexus are formed the two uterine veins which follow the uterine artery and return the blood to the internal iliac vein. The uterine plexus not only communicates above with the ovarian plexus and below with the vaginal and vesical plexuses but forms with them a continuous network of veins.

The veins from the ovary leave the organ largely from its hilum. These join with branches from the uterine plexus and from the uterine tube and form a dense valveless plexus, the pampiniform plexus, between the layers of the broad ligament. From this plexus the venous trunks arise which follow the arteries, the right ovarian vein opening into the inferior vena cava and the left ovarian vein into the renal vein at a right angle. These veins are imperfectly, if at all, supplied with valves, and the left one passing behind the sigmoid flexure of the colon is easily subjected to pressure when this viscus is filled.

The veins from the vagina form a plexus around this organ and freely communicate with the veins from the bladder, vulva, and rectum and become continuous with the great pelvic plexus. The veins from the uterine tubes enter the pampiniform plexus.

Especial attention is called to the pelvic plexus of veins because of its extent and location by the side of the upper portion of the vagina, along the margins of the uterus and the upper portions of the broad ligaments; its situation in the soft and yielding connective tissue of the pelvis; its practically valveless condition and its great dependence upon the aspirating power of the thorax for the onward flow of its blood. These conditions render these vessels very liable to engorgement as a result of any lesion affecting the vaso-motors of the pelvis or any condition affecting the general circulatory or respiratory systems.

The pelvic organs receive their nerve supply from the ovarian and hypogastric plexuses (sympathetic) and from the second, third and fourth sacral nerves (parasympathetic).

The ovarian plexus originates from the renal plexus. This in turn receives filaments from the coeliac, the aortic and the aortico-renal ganglia and is joined by the smallest splanchnic nerve. It follows the course of the ovarian artery and is distributed to the ovary and the fundus of the uterus.

The hypogastric plexus is formed by filaments from the aortic plexus and from the lumbar ganglia. It is placed between the two common iliac arteries in front of the fifth lumbar vertebra and the promontory of the sacrum. After sending some filaments to the fundus of the uterus it divides below into two portions situated at the sides of the rectum and vagina and called the pelvic plexuses.

The terminal branches of the hypogastric plexus with filaments from the (first and second) sacral ganglia, also from the anterior divisions of the second, third and fourth sacral nerves and from the nerves accompanying the uterine, ovarian and round ligament arteries, form the "pelvic brain" of Byron Robinson. This also called the "cervico-uterine" ganglion (Fig. 5), is a mass of gangliated gray matter situated on either side of the cervico-corporeal junction in the base of the broad ligament on a level with the middle of the cervix and about an inch lateral to it. Here it can easily be manipulated. Through it the nerves of the pelvic viscera are largely distributed. It is embedded in the pelvic connective tissue and through its gangliated cords, are intertwined arteries, veins and lymphatics.  It is so intimately connected with the urinary, genital and lower intestinal tract that irritation in one is often reflected in the other two. The reader is referred to "The Abdominal Brain," by Byron Robinson.

Fig. 6. Dorsal Position.