Lab 11 Pelvic Viscera
Introduction
In today’s lab we use two cases to explore the male and female pelvis. The first case
concerns a patient with uterine fibroids. The second case concerns a patient with prostatic
CA. Although you will only perform one case, according to the gender of your donor,
you should read both cases and be able to answer all the questions. Teach dissection
teams the performed the other procedure about your dissection, and they in turn will
share what they have learned with you. Despite the differences between the male and
female pelvis, the two procedures complement each other. Some of the things observed
in the male dissection are relevant to the female and vise versa.
Essential Question for Labs 10 and 11
How does studying the pelvis of one gender inform our understanding of the pelvis of the
other gender?
Guiding Questions:
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How does the male bony pelvis differ from the female pelvis?
How do the differences in the bony pelvis relate to child birth and support of the
abdominal and pelvic viscera? Which ligaments are especially important for
supporting the pelvic diaphragm of women?
Draw a line from the pubic symphysis to the sacrum. The line crosses which
organs?
In a transverse section, which organs are in the same plane as the heads of the
femur?
What are the relations of the pelvic diaphragm? The urogenital diaphragm?
Describe the nervous innervation, blood supply and lymphatic drainage of the
pelvis, perineum and ischiorectal fossa.
Which vessels contribute to the rich vascular bed surrounding the uterus?
How is the blood supply of the penis related to the prostate gland and the pelvic
and urogenital diaphragms?
Case 1 (#3-3): Fibroids
Students with male donors should read this case and visit the dissection of a female
donor.
CC: Pelvic Pain
Use the history and physical and laboratory data to answer the following questions:
Where was a mass found on palpation? Why would a mass in this location inspire
questions about urinary frequency and bowel habits?
Flash movie hp_1
A mass was detected in the uterus. Where was the mass palpated? Where is the uterus
normally found? How could the uterus migrate from the pelvis to the location where it
was palpated?
Flash movie hp_2
Does JC report any changes in urinary or bowel habits? Why are these notable?
Flash movie hp_3
Diagnostic studies:
MRI examination of the pelvis was obtained in three planes of section (radiology
resource). For these particular MRI sequences: Where do you expect to see fat? What
color is it in these images? (bright, dark, gray)
Flash movie ds_1
Bone is always black, but which is brighter, the muscles of the body wall or bone
marrow?
Flash movie ds_2
The contents of the urinary bladder demonstrate the color of stagnant water (also the
same as the slow moving water in a large capillary bed). Is the urine brighter or darker
than fat or muscle?
Flash movie ds_3
Is the uterus a uniform color? Describe its appearance. Look for a bright signal that you
can trace to the cervix. Based on the answer to the previous question, what is it?
Flash movie ds_4
Examine the urinary bladder and the rectum. How do your findings correlate with JC’s
comments on her urinary and bowel habits?
Flash movie ds_5
No ascites or significant pelvic lymphadenopathy is seen. Where should you search for
enlarged lymph nodes?
Flash movie ds_6
Impression: The uterus is markedly enlarged with multiple fibroids.
Operative Procedure
Lysis of adhesions, abdominal hysterectomy and bilateral salpingo-oophorectomy
1) You have already made this incision in an earlier lab. Review the landmarks, as
you follow the following description. A Pfannenstiel skin incision was made
roughly three centimeters above the symphysis pubis. The fascia would be incised
along the midline and the fascial incision extended bilaterally using sharp
dissection. Unlike your incision in lab 2 (where you performed an anatomic
dissection of the rectus muscles) the rectus muscles would not be divided.
Instead, the linea alba was divided in the midline. What embryonic remnant lies
deep to the linea alba that you should avoid cutting (because it sometimes has a
patent lumen that is continuous with the urinary bladder)?
Flash movie oa_1a
The pre-peritoneal adipose tissue was entered and the peritoneum was identified. The
peritoneum was grasped with smooth forceps, tented up, and sharply entered with a
knife. The peritoneal incision was extended superiorly and inferiorly for good
visualization of bladder and bowel. Why is there no rectus sheath between the rectus
muscle and the peritoneum?
Flash movie oa_1b
2) Pack the bowel away with moist sponges (a self-retaining retractor would be
placed in the actual procedure – you will have to make due!).
3) In JC’s case, inspection of the abdomen and pelvis revealed a large fibroid uterus
filling the pelvis and extending into the lower abdomen. How about in your
donor? Are a uterus and ovaries present? Where should the uterus lie relative to
bony landmarks and other organs? Is the uterus you observe antiverted or
retroverted? How can you tell?
Flash movie oa_3
4) JC’s uterus was essentially sitting on top of a very large degenerating fibroid
extending along the length of the elongated cervix and into the right broad
ligament. Adhesions were noted between the small bowel in the left adnexa as
well as from the left adnexa to the posterior aspect of the cervix. Sharp resection
was utilized to lyse the adhesions. Both adnexa were freed of adhesions.
Adhesions like these could be due to an inflammatory response. Do you observe
any adhesions in your donor? If so is there any evidence of disease or previous
surgery? Perform the following exploration before returning to the surgical
procedure:
a) Observe the peritoneum on the anterior abdominal wall near the midline.
Follow it to the pubic bone, where it reflects onto the urinary bladder. From the
bladder, the peritoneum reflects onto the uterus. The pouch that is formed
between the bladder (vesicle) and uterus is the vesicouterine pouch. Like the
uterus, the bladder expands into the abdomen as it fills. What would happen to
the peritoneal lining? If you wanted to insert a suprapubic catheter to drain the
bladder, would your needle need to puncture the peritoneal cavity in order to
reach the bladder?
Flash movie oa_4a
b) Continue to follow the peritoneum as it reflects off the uterus onto posterior
Fornix of the vagina and onto the rectum. Here it forms the rectouterine pouch.
c) Observe the adnexa (uterine appendages) projecting laterally from the uterus.
Palpate the uterine (Fallopian) tubes that lead to the ovaries. Observe how the
peritoneum is draped over these tubes like a towel on a towel rack to form the
broad ligament. Is the ovary anterior or posterior to the broad ligament?
Flash movie oa_4c
d) Different regions of the broad ligament have different names. The part
surrounding the uterine tube is the mesosapinx (salpinx = tube); surrounding the
ovary (and the ligament of the ovary, which connects the ovary to the uterus) is
the mesovarium; from the mesovarium to floor of the pelvis is the mesometrium.
How does the ligament of the ovary change during the embryonic descent of the
gonads? The ligament continues beyond the uterus as another named structure
that enters the internal inguinal ring. What is this structure and its homologue in
the male patient?
Flash movie oa_4d
5) Identify an avascular window below the left infundibulopelvic ligament
(suspensory ligament of the ovary), and open it with blunt dissection. What
structures are placed at risk by this procedure? Be sure to identify and protect
these structures before attempting this procedure! Repeat the procedure on both
sides.
Flash movie oa_5
6) Place two ties of the same color about the infundibulopelvic ligament and ligate it
(and its vessels, noted in the answer to step 5) between the ties. Repeat the
procedure on both sides.
7) Identify the uterine arteries. Try to trace them to their anastamoses with the
ovarian and vaginal arteries. What is the origin of the uterine artery and what are
its relations, as it travels to the uterus? (internal iliac base of broad ligament
superior to ureter)
Flash movie oa_7
Ligate the uterine arteries with two ties of the same color (choose a different color
than the ones you used for the ovarian arteries!
8) Clamp across the vaginal fornix where it joins the cervix. Separate the cervix
from the upper vagina with scissors liberating the uterus, fallopian tubes, ovaries,
and cervix from the vagina. The specimen would be sent to pathology. Close the
vaginal cuff with sutures.
Case 2: Prostatic CA
Students with female donors should read this case and visit the dissection of a male
donor.
CC: Routine check up
Use the history and physical and laboratory data to answer the following questions:
Which of AH’s presenting symptoms suggest prostatic cancer?
Flash movie hpa_1
What was the result of palpating the prostate? Describe the anatomical relationships that
allow you palpate it? What indications lead AH’s physician to palpate it?
Flash movie hpa_2
Operative Procedure
1. Position patient – supine with pelvis elevated on table at 20deg. Place a foley
catheter to keep the urinary bladder empty. Why would you want the bladder to be
empty?
Flash movie oaa_1
2. In AH’s case, a vertical midline incision from symphysis to umbilicus was used.
Your previous midline incision extended from the umbilicus to your Phannistal
incision. Continue your midline incision to the pubis through all the layers of the
body wall EXCEPT THE PERITONEUM. An alternative approach to a radical
prostatectomy is through the perineum by making an incision between the ischial
tuberosities that passed anterior to the anus. What tendon would you need to
divide and which structures would you pass between to get to the prostate?
Flash movie oaa_2
3. Reflect the peritoneum superiorly off the bladder. Why is it unnecessary (and
undesirable) to penetrate the peritoneal lining?
Flash movie oaa_3
4. In surgery, you would stay deep to the transversalis fascia to avoid the inferior
epigastric vessels. To widen your access it is permissible to detach the rectus
abdominis from its pubic attachment and reflect the recti laterally (surgeons
would only divide the medial attachment, if necessary). Trace the inferior
epigastric vessels inferiolaterally. What vessels do they connect with? Where is
this junction relative to the internal and external inguinal rings?
Flash movie oaa_4
5. Free peritoneum from internal inguinal ring on each side and trace the vas
deferens, beginning at the internal inguinal ring, to confirm it passes over the
ureter. You may see the obliterated umbilical artery (medial umbilical ligament)
that arises from the internal iliac (hypogastric) artery and passes to the umbilicus.
6. The following procedure mimics the lymph node dissection of the operation. See
if you find any nodes. Before you begin, what is the venous and lymphatic
drainage of the prostate?
Flash movie oaa_6
a. Identify the external iliac artery and vein and femoral nerve and use these
as the lateral border of the node dissection. Where do these vessels
originate? What do they become?
Flash movie oaa_6a
b. Be gentle with retraction for you may injure the femoral nerve. How
would a femoral nerve palsy manifest itself?
Flash movie oaa_6b
c. Search for nodal tissue medially and posteriorly. Expose the obturator
nerve. You should find vesicular arteries and veins that drain the
vesicoprostatic venous plexus. Because the vessels of this region connect
with the internal iliac vessels, the nodes you find here are internal iliac
nodes. Try to trace them to the internal iliacs. Since the obturator nerve
courses though here, it is placed at risk by the lymph node dissection.
How would injury to the obturator nerve manifest?
Flash movie oaa_6c
d. Resect the fibrofatty tissue from around the internal iliac artery and its
branches to the pelvis.
7. Retract the urinary bladder superiorly and pull away the retropubic fat from the
anterior and lateral surface of the prostate. You goal is to reveal the superficial
venous plexus (which you do not need to preserve) and the endopelvic fascia.
This fascia is the investing fascia of the underlying muscle layer and reflects on to
the prostate. Use the point of your scissors to enter this fascia laterally, deep in
the groove between the prostate and the muscle (the point of reflection) and
divide the endopelvic fascia to free the prostate. After dividing what you can see,
use your finger to bluntly divide the fascia posteriorly. What is this muscle called
and what is its function?
Flash movie oaa_7
8. Divide the puboprostatic ligaments. Which vessels are placed at risk by this
procedure?
Flash movie oaa_8
9. Using double ties to ligate the vessels, divide the tissue containing the deep dorsal
vein of the penis anterior to the urethra. What is the role of the deep dorsal vein in
sexual function?
Flash movie oaa_9
10. Separate the fibers of the levator ani from the prostate posteriolaterally to expose
the apex of the prostate and the urethra, as it emerges from the prostate. A
neurovascular bundle is placed at risk by this procedure, which you need to
identify and retract laterally. What types of neurons are found here? What are
their functions?
Flash movie oaa_10
11. Separate the posterolateral neurovascular bundles from urethra and apex of the
prostate. Is this neurovascular bundle in the pelvis or the perineum?
Flash movie oaa_11
12. Dissect around the urethra just below apex of the prostate. What muscle layer lies
inferior to your dissection and what is its function (it spans the between the two
inferior ischiopubic rami)?
Flash movie oaa_12
13. Partially divide the urethra at its junction with the prostate.
14. Divide the rectourethralis muscle with scissors. This muscle connects the rectum
to the perineal body. What is the perineal body? Which two diaphragms are
joined here? What role do these diaphragms play in maintaining urinary
continence?
Flash movie oaa_13
15. Bluntly dissect the space between the anterior and posterior sheathes of
Denonvilliers fascia (between the prostate and the rectum).
16. Expose the vas deferens and seminal vesicles on both sides. Separate the vesicles
from the bladder by blunt dissection. Beginning laterally, isolate the seminal
vesicles from the prostate. Divide the ampulla of the vas where they enter the
prostate.
17. At this point the surgeon would divide posterior vesicle neck and remove the
prostate. The cut ends of the urethra would then be re-anastamosis the bladder
neck. Instead, we will follow an anatomic procedure, but first: What feature of
the bladder neck does the surgeon wish to preserve to maintain urinary
continence?
Flash movie oaa_17
18. Make a midline incision from the partially transected urethra superiorly through
the prostatic urethra, through the anterior wall of the bladder so that the internal
structure of the bladder can be examined.
19. Observe the smooth-walled triangular trigone. Look for the ureters entering at the
non-urethra corners of the trigone. How does the embryonic origin and the
innervation of the trigone differ from the rough portion of the bladder wall?
Flash movie oaa_19
Urinary incontinence is a complication of this procedure. Patients with mild leakage are
advised to do Kegel (pelvic diaphragm) exercises. How does this help?
Flash movie oaa_20