11.12 Pelvic Viscera

Question 1

What is the most anterior structure in the pelvic viscera? Describe its shape

Answer 1

Bladder is the most anterior of the pelvic viscera.

It is shaped like a pyramid that is tipped to the side…

The apex of the pyramid points towards the pubic bone anteriorly and the base is posteriorly.

Question 2

What is the trigone of the bladder?

Answer 2

A triangular area located within (interiorly) the bladder at the base that has smooth walls (c.f. the loose folds making bumpy mucosa).

• On either side of the upper corners are the ureter openings into the bladder
• The tip of the triangle (points down) and is where the urethra drains.

Question 3

What are the major parts of the bladder?

Answer 3

• Apex – superiorly and anteriorly pointing towards the pubic symphysis.
• Body – The main part of the bladder, located between the apex and the fundus
• Fundus (or base) – Located posteriorly. It is triangular shaped, with the tip of the triangle pointing backwards.
• Neck – narrowing that joins the bladder to the urethra (is posterioinferior)

Question 4

All pelvic viscera require stabilisation. Where is the bladder stabilised from?

Answer 4

Stabilisation happens at the neck of the bladder by ligaments (mainly pubovesicle) - connecting to the pubic bone anteriorly. Ligments of the pelvis are condensations of the loose connective tissue around the nerves and vessels.

This is because you can’t stablise the fundus of the bladder because it needs to expand for urine collection.

Question 5

The posterior wall (base) of the male bladder is related to several important structures.

What are they and describe their anatomical relationship to the bladder.

Answer 5

Components of the male genitourinal tract.

• The prostate gland is immediately related to neck of bladder and surrounding first part of the urethra.
• The vas deferens is directly related to the last parts (just before entry point) of the ureters. They run over the top and cross over them on either side.
• The seminal vesicles also rest on the inferior part of the base of the bladder just under the vas deferens course and empties into the prostate glands

Question 6

Describe the path of the ureters from the kidneys down to the bladder

Answer 6

Ureters (on psoas in line with tip of transverse processes) Pelvic part of the ureters dip of pelvic brim (narrowing) running on lateral wall of the pelvis and crosses towards the posteiror aspect of the bladder (base) to enter at upper point of trigome.

Question 7

Describe the path of the vas deferens from the testes to the prostate gland (with special mention of the relationship to the bladder)

Answer 7

The vas deferens originates at epididymis of testes and ascends and traverses the inguinal canal through the superficial ring, inguinal canal and exits deep ring (def. in transversalis) along lateral wall of pelvis and approaches the base of the bladder from behind crossing the ureter and joins the duct of the seminal vesicle and form an ejaculatory duct (final common pathway) and enters the urethra.

Question 8

A structure does cross the ureters in the female anatomy. What is this? Describe

Answer 8

The uterine artery travels towards the uterus (from side walls on top of ureter towards uterus).

Question 9

Describe the prostate gland

What structure supports it?

Answer 9

It situated between neck of bladder and the urogenital diaphragm. It is often described as chestnut sized.

Levator ani (pubo prostaticus) sits on the lateral side of it (slings surrounding the prostate holding it and the bladder in position).

Question 10

What is special about the prostatic part of the urethra?

Answer 10

It has a crest/mound/bulge called the prostatic crest with the opening of the ejaculatory duct on each side and the opening of the prostatic ducts into it.

Question 11

Describe the relationship of the prostate gland to the rectum.

How is this applicable to the clinical setting?

Answer 11

The prostate sits just anteriorly to the rectum.

The posterior surface is palpable on per rectal examination. Anterior tip of the fingers on the anterior wall is the prostate gland: size and consistency can be felt.

Question 12

What is the most important lobe of the prostate gland? Why is this so?

Answer 12

The median/middle lobe (the star on the diagram)

This is the part that enlarges on BPH. Cancer the gland becomes very hard and loses the typical contour (palpable on examination). But for BPH it doesn’t lose normal contour but does enlarge (it is still rubbery).

Between prostatic part of the urethra and the ejactulatory duct and thus has an impact on flow of urine.

Question 13

What is the most common positioning of the uterus in relation to the vagina? Describe it

Answer 13

Anti-verted and anti-flexed

The uterus is bent forwards on the vagina and superior bladder.

• Anti-verted means bent forwards on the top of vagina
• Anti-flexed means it is bent forwards on itself

Question 14

What is uterine retroversion?

Answer 14

Uterus can be anything between anteverted to retroverted (bends back on vagina and directly relates to rectum

Rectroversion related to back pain in period and during labour

Question 15

How does the uterus size vary with pregnancy?

Answer 15

Uterus size varies w/ number of pregnancies (never completely involutes back). It is often described as having the dimensions 8x5x3cm

Question 16

Describe the shape of the uterus

Answer 16

It is a hollow structure with a triangular cavity pointing downwards. Each upper angle is related to a uterine tube.

Question 17

What are the main parts of the uterus?

Answer 17

• Fundus is the convex part of uterus which houses the entry of uterine (fallopian) tubes.
• Below that is the Body of the uterus and it tapers down in size
• The bottom 1/2 cm of the body becomes the isthmus which is continuous with the cervix.

Question 18

Describe the cervix and its openings

Answer 18

Cervix is usually 2-3cm in length

• It has an internal uterine opening (opening that relates to the uterine cavity itself called the internal os)
• There is also an external opening into the cavity of the vagina called the external os (this is what is visible and palpable on vaginal examination and is what is scarped in pap smears.

Question 19

How is the cervix related to the vagina?

Answer 19

Cervix sits down into the opening of vagina so the vagina extends up and cups the external os. This creates the fornix of the vagina = space in vagina above external os (a ring around it).

The posterior fornix behind forms the lowermost part of cervix, anterior fornix in front and lateral fornices.

Question 20

The uterus is limited in where it can be stabilised in the pelvis from because it needs the ability to be able to extend and expand to accomodate pregnancy.

Where is the uterus stabilised?

Answer 20

Cervix is what is stablised.

• Pubovaginalis in the vagina indirectly stablises the uterus.
• Mainly Condensations of pelvic fascia around nerves and vessels and alone create a series of ligaments that holds the uterus in position (it holds a large weight in pregnancy).

Question 21

What are the ligaments that stablise the cervix?

Answer 21

Series of fascial ligaments (condensations) connecting cervix to the walls of the pelvis.

• Pubocervical ligaments come forward but are the least substantial (not in diagram)
• Most significant are the lateral cervical (cardinal ligament) and are true fascial condensations around the uterine artery.
• Also rectouterine ligaments going back (also called uterosacral) going to the sacrum.

Question 22

What are things that can go wrong with the positioning of the stabilsing ligaments of the cervix

Answer 22

Trauma of childbirth and withdrawal of oestrogen (around menopause) can cause these structures can loose their significance and strength and function. This leads to uterus and cervix starting to move out of position often also having a loss of support structure to the bladder.

• Uterus and cervix dip into the top of the vagina (type of prolapse). Severe prolapse can appear at the inferior regions of the vagina.
• Cystocele the bladder falls back into the vagina
• Rectocele with the rectum into the vagina.

Question 23

Describe the formation of the broad ligament

Answer 23

The uterus is covered in peritoneum from above. Most of the ant. wall all of the top and all of the posterior wall is covered.

It also sweeps out to the side wall of the pelvis forming a double fold of peritoneum over the uterine tubes = broad ligament which is a double fold of peritoneum suspended from the uterine tubes. (it is not a ligament it is the peritoneum).

(it is effectively as if the uterine tubes are a curtain rod holding up a large sheet of fabric draping over either side.

Question 24

Does the broad ligament have a support function for the uterus?

Answer 24

No

Question 25

Describe the parts of the uterine (fallopian) tube

Answer 25

* The first part of the uterine tube is within the wall of the uterus and is called **intramural** part * Then the **isthmus** is the straight part directly lateral to that * The **ampulla** is the end part that progressively widens * The widest parts is the **infundibulum** * The tubes end in **fimbria** (finger like projections that come out).

Question 26

Where is the most common site of ectopic pregnancy?

Answer 26

In the uterine tube.

Question 27

Ectopic pregnancies sometimes (rarely) occur in the abdominal cavity. How could this occur?

Answer 27

Fimbria come out to the opening of the fallopian tube through the **back** of the broad ligament which is actually into the peritoneal cavity. Uterus and uterine tubes are below (extraperitoneal) while the uterus but the broad ligament are within the peritoneal cavity (delineating it). The ovary is stuck on the back of the broad ligament (technically in the peritoneal cavity) - so it releases the egg into the peritoneal cavity for the fallopian tubes to take and lead it extraperitoneally into the uterus.

Question 28

The ovary is situated on the lateral walls of the pelvis and has key relations. Name the relations surrounding the ovaries

Answer 28

* The ovaries sit within the bifurcation of the common ileac into internal and external ileac vessels. * It sits on the obturator nerve as it tracts around side wall of the pelvis and the nerve also supplies parietal peritoneum of the pelvis. Add picture slide 28

Question 29

An ovarian cyst could produce pain referred to the medial knee. Why?

Answer 29

Reffered pain to the site of cutaneous supply of the obturator nerve because it is closely related to the ovaries (medial knee pathology).

Question 30

Where is the rectum situated in the pelvic cavity?

Answer 30

Rectum commences at **S3** extending from there down to the anorectal junction and becomes the anal canal. Rectum sits **back** in the **midline** in the concavity of the sacrum.

Question 31

Describe the rectum in terms of the covering by the peritoneum [3 parts]

Answer 31

1. First part has peritoneum covering the lateral and anterior aspect 2. Second part of the rectum only has peritoneum over the front of it 3. Third part is below the peritoneum as it goes onto the top of the bladder

Question 32

Where is the ampulla of the rectum? What does it contain?

Answer 32

Ampulla is the dilated lower part of the rectum It contains the feaces waiting for puborectalis to relax and sphincters to relax for defecation.

Question 33

The blood supply to the pelvis comes from 2 regions/sources of the body. What is meant by this?

Answer 33

From Above or From The Sides Vessels descend from the abdomen * Eg. ovarian arteries and testicular arteries from abdominal cavity * Also the Inferior mesenteric artery (to descending colon and sigmoid) changes its name to **rectal artery** and comes down to supply pelvic structures. Vessels from the lateral walls of the pelvis: (highly variable) * From the **anterior division internal ileac artery** on each side walls. Only the anterior branches gives the visceral contents (the parietal supply the walls)

Question 34

What is the major blood vessel supplying the bladder? This vessel is supplemented by another blood vessel. This supplementation is this different in the males nad females. How so?

Answer 34

Superior vesical artery from each internal ileac artery. **Male:** * Supplemented by the **inferior vesicle artery** that is also supplying the prostate and vas deferens. **Female:** * Usually the **vaginal artery** There is also a middle rectal branch of internal ileac artery

Question 35

Describe the blood flow to the uterus

Answer 35

The **uterine artery** coming from internal ileac vessel on the side will comes in at the level of the cervix and crosses over the top of the ureters [this is important to historectomy and tying off blood supply]. The uterine artery anastomoses with the **ovarian artery** which comes from the abdominal aorta to supply the ovaries and descend over the pelvic brim and tracts along uterine tube supplying that as well. From the side wall of the pelvis to the cervix, the uterine vessels get condensation ligaments and create the lateral cervical ligament.

Question 36

Describe the venous drainage of the pelvic viscera

Answer 36

Veins form plexuses which surround the viscera before they drain into the internal ileac veins (valveless plexuses - propensity for shared metastatic spread eg. prostate to the sacrum and vertebral column)

Question 37

Describe the nerve supply to the pelvic cavity

Answer 37

The bulk of **visceral** supply comes from a **pair of inferior hypogastric plexi in the pelvis**. * Sympathetics descending from lower thoracic/upper lumbar region and parasympathetic component from the s**acral plexus.**