Chapter 35: Female genitalia
The female genital organs comprise the ovaries, uterine tubes, uterus, vagina, and external genitalia (fig. 35-1). The vagina is situated partly in the pelvic cavity and partly in the perineum. The internal organs can be examined by an electrically lit tubular instrument inserted into the peritoneal cavity (laparoscopy).
An ovary is an ovoid gland that produces oocytes and secretes steroid hormones. It is commonly situated on the lateral wall of the pelvis (typically in the angle between the external iliac vein and the ureter), where it can be palpated bimanually. The ovary presents tubal and uterine ends, medial and lateral surfaces, and mesovarian and free borders. The superior, or tubal, end, closely related to the uterine tube, is attached to the suspensory ligament ofthe ovary. The inferior, or uterine, end is attached to the ovarian ligament. The medial surface is related to the uterine tube and the ileum. The lateral surface is in contact with the parietal peritoneum that lines the side wall of the pelvis. The anterior, or mesovarian, border is attached to the mesovarium, and it contains the hilum of the ovary. The posterior, or free, border is related to the uterine tube and ureter.
The ovary is anchored to the posterior aspect of the broad ligament by a double fold of peritoneum, the mesovarium, which is continuous with the so-called germinal epithelium around the ovary. The suspensory ligament of the ovary (or infundibulopelvic ligament) ascends to become lost in the connective tissue of the pelvis. The ovarian artery descends in the suspensory ligament and, by way of the broad ligament and mesovarium, enters the hilum of the ovary. The ovarian ligament connects the ovary to the body of the uterus, immediately posterior to the opening of the uterine tube.
The uterine tubes are paired conduits between the ovaries and the uterus. The uterine tube transmits oocytes from the ovaries and spermatozoa from the uterus. It is the usual site of fertilization, and it conveys the early embryo to the uterine cavity.
The uterine tubes develop as outgrowths of the peritoneal cavity; they maintain this continuity and thereby allow communication between the peritoneal cavity and the exterior of the body. The Greek word salpinx, meaning "tube," is used in such compounds as mesosalpinx.
Each uterine tube is situated in the superior, free border and between the layers of the broad ligament. The uterine tube is subdivided into four parts, from lateral to medial: the infundibulum, ampulla, isthmus, and uterine part. The infundibulum, which is closely related to the ovary, contains the abdominal opening of the uterine tube, by which the tube is in communication with the peritoneal cavity. Oocytes pass from the ovary through the abdominal opening and along the uterine tube. The fimbriae are irregular fringes that project from the margin of the infundibulum, and one (ovarian fimbria) may be longer than the others. The ampulla, the longest and widest part, continues gradually into the isthmus. The uterine part, which lies in the wall of the uterus, contains the uterine opening of the uterine tube.
Patency of the uterine tubes can be demonstrated radiographically (hysterosalpingography) by the injection of a radio-opaque medium into the uterus (fig. 35-3).
The uterus is a muscular organ in the lining of which the embryo becomes implanted and in which the embryo and fetus develop. The uterine cavity receives the openings of the uterine tubes, and the uterine cavity and vagina (the "birth canal") allow the exit of the fetus at birth (fig. 35-6). The Greek words hystera and metra are used in such compounds as hysterectomy and endometrium. The uterus has three layers: a mucosa (the endometrium), a muscular coat (the myometrium), and a serosa (the perimetrium).
The nulliparous uterus resembles an inverted pear and consists of two main parts: the body and the cervix. The body is twice as long as the cervix, whereas the converse is true in the newborn. The body includes the fundus, which is the portion that lies superior and anterior to the openings of the uterine tubes. The body is usually tilted anteriorly onto the bladder (anteflexion, see fig. 35-4), which is separated from the uterus by the uterovesical pouch. Superior and posterior, the body is separated from the rectum by the recto-uterine pouch (see fig. 35-4), which usually contains coils of ileum. Right and left margins are anchored to the broad ligaments. The region between the body and cervix is referred to as the isthmus: during pregnancy, it is known as the "lower uterine segment." The cavity of the isthmus was formerly called the "internal os." The cervix extends inferiorward and posteriorward and usually forms approximately a right angle with the vagina (the angle of anteversion, see fig. 35-4). As the bladder fills, the uterus tends to become retroverted. The cervix may be considered in two parts: (1) a supravaginal portion superior to the limits of the vagina and (2) a vaginal portion, which projects into the cavity of the vagina (see fig. 35-4). The cavity of the uterine body, which is somewhat triangular in coronal perspective (see fig. 35-2), is slit-like in sagittal section (see fig. 35-1). The canal of the cervix communicates with the vagina by the external os, which is bounded by anterior and posterior lips. The entire uterine cavity can be demonstrated radiographically by hysterosalpingography (see fig. 35-3). The uterus can be palpated bimanually (fig. 35-7). Dilatation (of the cervical canal) and curettage (scraping of the uterine lining) are performed for diagnostic or therapeutic purposes.
The uterus is supported by being anchored to the vagina and by its peritoneal and fascial attachments to nearby structures. The peritoneum is reflected from the bladder (uterovesical pouch) to the isthmus uteri and then over the fundus and onto the posterior aspect of the cervix (recto-uterine pouch) and vagina (see figs. 35-1 and 35-4).
The peritoneum that covers the uterus continues laterally as a double fold known as the broad ligament (figs. 35-2 and 35-8). The ligament extends to the lateral wall of the pelvis and serves as a mesentery for the uterine tube, which lies between its two layers. This part is the mesosalpinx, whereas the part adjacent to the uterus is called the mesometrium. The posterior layer of the broad ligament forms the mesovarium. In addition to the uterine tube, the broad ligament contains connective tissue (the parametrium), the uterine and ovarian vessels, the round and ovarian ligaments, and some embryonic remnants (e.g., the epoophoron, which consists largely of a duct parallel to and below the uterine tube) (fig. 35-8B). The round ligament is a fibrous band attached to the uterus immediately inferior to the entrance of the uterine tube. It extends laterally and anteriorly, hooks around the inferior epigastric artery, traverses the inguinal canal, and terminates in the labium majus. The round ligament is accompanied in the fetus, and occasionally in the adult, by a process of peritoneum, the processus vaginalis. The visceral pelvic fascia on the lateal aspect of the cervix is thickened as the lateral (or transverse) cervical (or cardinal) ligament and as the uterosacral ligament on the posterior aspect (see fig. 35-5).
The uterine arteries (fig. 35-9) provide the main blood supply. Each artery ascends between the layers of the broad ligament, near the lateral margin of the body, and supplies branches to both anterior and posterior surfaces. The uterine venous plexus is connected with the superior rectal vein, thereby forming a portalsystemic anastomosis.
The fundus and upper part of the body drain into the lumbar (aortic) nodes, the lower part of the body into the external iliac nodes, and the cervix into the external and internal iliac and the sacral nodes.
The vagina serves for copulation, as the lower end of the birth canal, and as the excretory duct for the products of menstruation. The cavity of the vagina communicates with that of the uterus, and it opens into the vestibule below. The vagina extends inferiorly and anteriorly, parallel to the plane of the pelvic inlet.
The anterior and posterior walls of the vagina are about 7.5 and 9 cm long, respectively. They are highly distensible and are in contact inferior to the cervix. The recess between the vagina and the vaginal part of the cervix consists of a continuous anterior, lateral, and posterior fornix. The posterior fornix, which is the deepest, is related to the recto-uterine pouch. The opening of the vagina into the vestibule may be partially closed by a fold called the hymen (see fig. 38-5).
The vagina is related anteriorly to the cervix, ureters, and bladder and is fused with the urethra. Posteriorly, the vagina is related to the recto-uterine pouch, the rectum, and the perineal body. The lateral fornix of the vagina is related to the ureter and uterine artery. The pubococcygeal muscles act as a sphincter for the vagina. The vagina is supplied by branches (including uterine and vaginal) of the internal iliac artery.
The vagina and cervix can be inspected through a speculum in the vagina. Digital examination per vaginum may be combined with palpation through the anterior abdominal wall by the other hand (bimanual examination). The following structures are palpable per vaginam:
1. Anteriorly-urethra, vaginal part of cervix, distended bladder, and body of uterus bimanually
2. Laterally-ureters and displaced or enlarged ovaries and uterine tubes bimanually
3. Posteriorly-rectum, any mass in the rectouterine pouch, and sometimes sacral promontory
4. Vaginal (Papanicolaou) smears taken from the cervix are used in histodiagnosis.
35-1 Where is the ovary situated?
35-2 Is the ovary covered by peritoneum?
35-3 What are the openings of the uterine tube?
35-4 What is the broad ligament?
35-5 Which Latin terms and Greek roots are associated with the ovary, uterine tube, and uterus?
35-6 What is the endometrium?
35-7 What are anteflexion and anteversion of the uterus?
35-8 What is the inferior opening of the uterus termed?
35-9 What is hysterosalpingography?
35-10 What are the peritoneal relations of the uterus?
35-11 By what is the uterus supported?
35-12 What is the epoophoron?
35-13 What are the surgical approaches to the uterus?
Figure 35-1 Median section of the female pelvis, including a medial view of the right lateral pelvic wall. (Modified from Appleton, Hamilton, and Tchaperoff and from Shellshear and Macintosh.)
Figure 35-2 Female reproductive organs, posterior view.
Figure 35-3 Hysterosalpingograms, showing the uterus and uterine tubes. In A, note the cavity of the uterus, uterine tubes, and the bilateral "spill" of the radio-opaque medium into the peritoneal cavity, thereby demonstrating the patency of the tubes. B, View from in anterior and superior. Note the slit-like shape of the uterine cavity in this view. Note also the thickness of the uterine wall. (A, Courtesy of Sir Thomas Lodge. B, Courtesy of Robert A. Arens, M.D., Chicago, Illinois.)
Figure 35-4 The uterus. A shows the parts of the organ. B shows the normal position of anteflexion and anteversion. C shows the angle (a) of anteversion. D represents a retroverted uterus. E shows the uterovesical and recto-uterine pouches. F demonstrates the principle of (1) abdominal and (2) vaginal hysterectomy (arrows).
Figure 35-5 Horizontal section of the pelvic viscera, showing the ligaments of the uterus. The arteries shown are, from posterior to anterior, the middle rectal, uterine, and inferior and superior vesical.
Figure 35-6 A, Fetus at term in utero, cephalic presentation. Note the fetal vertebrae and ribs, bones of the limbs, and skull. The parietal bones have overlapped the frontal bone at the coronal suture. H, Infant during birth. Cf. fig. 31-6, lowest position (A, Courtesy of Robert A. Arens, M.D., Chicago, Illinois. B, Courtesy of Robert P. Ball, M.D., Oak Ridge, Tennessee.)
Figure 35-7 Bimanual palpation of the uterus. (After Kelly and Noble.)
Figure 35-8 Sagittal sections of (A) left and (B) right broad ligaments, showing their relationships to the ovaries and uterine tubes. B shows embryonic remnants.
Figure 35-9 The blood supply to the female reproductive system. Extensive anastomoses occur between the ovarian and uterine arteries. Cervical branches of the uterine arteries anastomose across the median plane. The four-tiered concept of the reproductive system (A,B,C,D) is based on anatomical, physiological, and pathological data and may perhaps have embryological implications. For details see R. Contamin et al., Gynecol., 28:235-252, 1977.