FOCUS QUESTIONS and ANSWERS:

1. Note the difference between male and female in the subpubic angle, the angle formed by the subpubic arch. What are other sex differences in the pelvic skeleton?

Structure/Section	Female	Male
pelvic inlet	oval and rounded	heart-shaped
pelvic outlet	large	small
pubic arch and subpubic angle	wide	narrow
iliac wings	flared	less flared

2. Define the rectum.

The rectum begins where the peritoneal investment of the sigmoid ends, at approximately the level of S3. It curves into the pelvic diaphragm, dilating just above the pelvic diaphragm as the rectal ampulla, and ends four centimeters below and in front of the coccyx. It continues as the anal canal after piercing the pelvic diaphragm. The rectum is about twelve centimeters long altogether. Its anterior surface contacts the vagina in females or the prostate gland in males.

3. Define and note the flexure between rectum and anal canal. What muscle assists in maintaining this flexure?

The anterior flexure at the anorectal junction is held by the sling of the puborectalis portion of the levator ani muscle, which passes posteriorly around the anorectal junction.

4. On the sagittally-sectioned female specimen, trace the peritoneum from the ventral abdominal wall; examining the vesicouterine pouch and its manner of reflection from the bladder to the uterus. Onto what part of uterus does it reflect? (

The peritoneum on the superior surface of the bladder reflects onto the uterus at the isthmus, just superior to the cervix.

5. Trace the peritoneum across the uterus and define the rectouterine pouch. Note peritoneum on the posterior wall of the vagina. From what point does the peritoneum reflect to the rectum? What is the significance of this?

The peritoneum of the rectouterine pouch lies in contact with the posterior fornix of the vagina. This allows incisions, punctures, or lacerations of the posterior fornix of the vagina to open the peritoneal cavity. (This is often how eggs are harvested these days.)

6. Within the broad ligament, locate the ovarian ligament and the round ligament of the uterus. Consider development and continuities of these structures.

The proper ovarian ligament and the round ligament of the uterus are both remnants of the gubernaculum. They are continuous with one another where they contact the lateral surface of the uterus inferior to the uterine tube.

7. Locate and define the peritoneal fold called the suspensory ligament of the ovary. What does it contain?

The suspensory ligament of the ovary contains ovarian vessels, autonomic nerves, lymphatics, and extraperitoneal connective tissue.

8. Strip the peritoneum from the suspensory ligament of the ovary on one side and trace the ovarian artery and vein. What are their sources?

The ovarian artery branches from aorta. The right ovarian vein drains to inferior vena cava. The left ovarian vein drains to left renal vein. (This is analogous to testicular vessels in males.)

9. What is the complete area of distribution of the ovarian artery? (

The ovarian artery supplies the ovary, mesovarium, and infundibulum of the uterine tube.

10. Locate a ureter. Note its relation to uterine artery. Trace it to the bladder and posteriorly to the brim of the pelvis, noting course, relation to peritoneum, and blood supply.

The ureter passes over the pelvic brim just medial to the ovarian vessels, usually at the bifurcation of the common iliac artery. The ureter then descends and passes anteriorly within the pelvis. It is crossed superiorly by the uterine artery ("bridge over water") before it turns medially to enter the posterior wall of the bladder.

11. Trace the round ligament from the uterus to the deep inguinal ring. Where does it attach?

The round ligament of the uterus attaches to the lateral surface of uterus, below and anterior to the intramural portion of the uterine tube. It helps to hold the fundus of the uterus forward (anteverted).

12. What structures support the uterus?

The round ligament of the uterus helps to hold the uterus in an anteverted position superior to the bladder. The cardinal ligaments and the endopelvic fascia around the uterine vessels helps to fix the cervix in place, as do the rectouterine ligaments. Even the broad ligament lends a slight amount of support to the uterus. (Anterversion of the uterus seems to be key, since retroversion is associated with prolapse of the uterus into the vagina.

13. Explore the female urethra, noting length, sphincter muscle, and relation to vagina. Note specifically the relation of the orifice to the anterior vaginal wall. What is the significance?

The urethra is about four centimeters long. It is homologous to male prostatic/membranous urethra. Its orifice is within the vestibule of the vagina, immediately in front of the vaginal orifice.

14. Define the ampulla of the ductus deferens. Is it covered by peritoneum?

The ductus deferens is covered by peritoneum, but its ampulla is not. The upper end of the seminal vesicle may contact peritoneum, otherwise it is inferior to the peritoneum lining the rectovesical pouch.

15. What is the rectovesical pouch?

The rectovesical pouch is the reflection of peritoneum between the rectum and the bladder. This of course only occurs in males.

16. Where does the transition of the epididymis to the ductus deferens occur?

It occurs at the tail of the epididymis on the posteroinferior aspect of the testis.

17. Locate the anterior division of the internal iliac artery and note how it terminates by dividing into the inferior gluteal and the internal pudendal arteries. These exit the pelvis below the lower border of the piriformis muscle. What are other relations? The internal pudendal and inferior gluteal (the larger of the two) arteries are terminals of the anterior division of the internal iliac artery. They arise from a common trunk either within or outside the pelvis. The internal pudendal artery exits the greater sciatic foramen between the piriformis and coccygeus muscles, crosses the iliac spine to pass through the lesser sciatic foramen, and enters the pudendal canal. The inferior gluteal artery passes between the second and third sacral nerves to leave the pelvis below the piriformis muscle.

18. Do you have an "aberrant obturator artery", which arises from the inferior epigastric artery and accompanies the obturator nerve?

An aberrant obturator artery takes its origin from the inferior epigastric or, rarely, from the external iliac itself. It would descend along the brim of the pelvis to the obturator foramen.

19. Locate the sympathetic trunk entering the pelvis along the medial border of the pelvic sacral foramina. Note number of ganglia, gray rami communcantes, and sacral splanchnic nerves.

Both sympathetic trunks descend on the anterior surface of the sacrum in the extraperitoneal connective tissue. There are usually four ganglia in the sacral region, one opposite the upper three sacral segments and one beneath the fourth and fifth segments of the sacrum. The two trunks typically unite over the coccyx to form the "ganglion impar". Sacral splanchnic nerves are slender fibers leaving the anterior surface of the sacral sympathetic trunk ganglia to enter the inferior hypogastric plexus on the sides of the rectum. Gray rami communicantes also leave the lateral side of the sacral sympathetic trunk to reach the sacral ventral primary rami as they emerge from the anterior sacral foramina.

20. How many pelvic splanchnic nerves are there?

The pelvic splanchnic nerves represent the sacral portion of the craniosacral outflow or parasympathetic portion of the autonomic nervous system. The pelvic splanchnic nerves spring from the ventral rami of the second, third, and fourth sacral nerves. The contribution from the third sacral nerve is usually the largest. From three to ten strands of nerves pass forward and become incorporated into the inferior hypogastric plexus.

21. What is the puborectalis muscle? What is its significance? The puborectalis muscle is the most medial portion of the levator ani muscle. It passes around the terminal rectum to form the puborectal sling, which kinks the anorectal junction forward to assist in maintaining fecal continence. This muscle marks the transition from rectum to anus.

22. Define the urogenital hiatus. What does it transmit? (

The passage (transmission) of the urethra/vagina and anus through the pelvis requires a separation of the two halves of the pelvic diaphram in front of the rectum. This is the urogenital hiatus.

23. Do you find muscular (deep) branches of the perineal nerves? (

The deep perineal nerve innervates all of the muscles of the urogenital triangle via slender branches that may be difficult to locate.

24. What is the source and drainage of the deep dorsal vein of the clitoris/penis and the dorsal veins and arteries of the clitoris/penis?

The deep dorsal veins drain into the vesical venous plexus. The "normal" dorsal veins drain into the superficial external pudendal vein. The dorsal arteries come from the internal pudendal arteries.

25. What is the function of the perineal membrane?

This membrane covers the anterior part of pelvic outlet. It aids in support of the pelvic viscera and as an attachment for perineal structures. It is pierced by the arteries of the erectile bodies and the dorsal arteries and nerves of the clitoris or penis.

26. What is the source of the deep (central) artery of the clitoris/penis?

This artery is a branch of the internal pudendal artery.

27. What gland is embedded in the sphincter urethrae muscle in males?

In males, the bulbourethral glands (Cowper's glands) are embedded in the urethrae muscle. In females, the greater vestibular gland is the homologous structure, but it is not associated with the sphincter urethrae muscle. (The greater vestibular glands lie posterior to the vestibular bulb, under the cover of the bulbospongiosus muscle.)