Anatomy of the Lateral Pelvic Wall and Mass

Question 1

What is the consequence of having a foreign object (mass) in pelvic cavity?

Answer 1

Impingement on other structures as pelvic cavity is small

Question 2

How to identify an obturator vessel?

Answer 2

Any time a vein, artery or nerve heads towards obturator canal it is an obturator vessel

Question 3

What are the muscles of the lateral pelvic walls?

Answer 3

Levator ani
Coccygeus
Obturator internus
Piriformis

Question 4

Which muscle is deep to levator ani?

Answer 4

Obturator internus

Question 5

List the muscles invovled in lateral rotation of the hip

Answer 5

Obturator internus

Piriformis

Question 6

What is the arterial supply of lateral pelvic wall?

Answer 6

Majority of arteries of pelvis and perineum arise from internal iliac artery

Extensive anastamoses

Question 7

What are the exceptions to arterial supply from internal iliac artery?

Answer 7

• Gonadal artery: L2 abdominal aorta

- Superior rectal artery: Continuation of inferior mesenteric

Question 8

What are the visceral and parietal divisions of the internal iliac artery (male)?

Answer 8

Visceral: anterior division
Parietal: posterior division

Question 9

Which artery heads towards obturator canal?

Answer 9

Obturator artery

Question 10

Which artery connects embryo’s internal iliac to the placenta?

Answer 10

Median umbilical ligament - remnant of the umbilical artery

Question 11

Which arteries supply bladder (male)?

Answer 11

Superior and inferior vesicle

No inferior vesicle artery in female, however this is being disproved by research papers

Question 12

Which is the main pelvic artery that supplies most of the structures (male)?

Answer 12

internal pudendal

exits at greater sciatic foramen and re enters at lesser sciatic foramen

Question 13

List the arterial supply of the perineum

Answer 13

internal pudendal artery
perineal artery
Posterior scrotal
Anterior scrotal
Deep artery of penis
Dorsal artery of penis

Question 14

Artery supplying corpus cavernosum?

Answer 14

Deep artery of the penis

Question 15

Where does uterine artery come from?

Answer 15

Anterior division of common iliac

Question 16

Which surgical procedure requires ligation of uterine artery?

Answer 16

Hysterectomy

Question 17

Which female pelvic artery is homologous to vas deferens artery?

Answer 17

Uterine artery

Question 18

Name the branch of the uterine artery that supplies vagina?

Answer 18

Vaginal artery

Question 19

Which female pelvic artery is homologous to inferior vesical artery in males?

Answer 19

Vaginal artery (variable, 60-70% of the time)

Question 20

List the two sites of anastomoses of pelvic arteries in females

Answer 20

1. Between uterine artery and ovarian artery

2. Between uterine artery and vaginal artery

Question 21

What is the clinical importance of uterine artery ligation?

Answer 21

Ureter passes right underneath the uterine artery. If you ligate the uterine artery, be aware of the proximity of the ureter.

Question 22

Which artery gives of branches that anastomose further with vaginal artery?

Answer 22

Internal pudendal artery

Question 23

List the arteries of the female perineum

Answer 23

Internal pudendal artery
Inferior rectal artery
Labial arteries 
Perineal arteries
Dorsal artery of clitoris

Question 24

What is the most important feature of venous drainage of pelvis?

Answer 24

Formation of venous plexuses

Question 25

Describe venous drainage of pelvis

Answer 25

Drain mainly to internal iliac vein
- some will drain via superior rectal into hepatic portal system

• some will drain via lateral sacral veins into internal vertebral venous plexus

Question 26

Clinical significance of venous plexus of pelvis

Answer 26

Infection and cancer can spread to vertebral column via lateral sacral venous plexuses (on either side of sacrum)

This is also true of pre-sacral plexus.

Question 27

What are the nerves of the lateral wall?

Answer 27

Obturator Nerve* - L2,3 4
Sciatic nerve
Pudendal
Nerve to LA
Sacral plexus 
Pelvic splanchnic nerves - parasympathetic, supply pelvic organs

Question 28

What is the origin of most nerves of lateral wall

Answer 28

Sacral plexus

Question 29

What are the main groups of the lymphatics of the pelvis?

Answer 29

1. Para rectal - either side of rectum
2. Sacral
3. Internal iliac
4. External iliac
5. Superficial inguina
6. Deep inguinal
7. Common iliac
8. Inferior mesenteric
9. Lumbar

Question 30

General rules of pelvic lymphatics

Answer 30

Superior Pelvic Viscera:

• external iliac nodes
• common iliac, aortic, thoracic duct, venous system

Inferior Pelvic Viscera:

• deep perineum
• internal iliac nodes
• common iliac, aortic, thoracic duct, venous system

Superficial perineum:
- superficial inguinal nodes

Question 31

Are the lymph node patterns and its drainage fixed?

Answer 31

Nope, highly variable
This is only a general idea
High cross-over
Cancer can spread into any direction
Pattern not sufficiently predictable to anticipate spread.

Question 32

Describe trans-peritoneal spread

Answer 32

Usually the peritoneum draping over pelvic organs acts a as a barrier. However, it is only a single celled membrane, hence aggressive cancers can penetrate and the peritoneum is no longer a barrier and aids spread instead.

Also, little cells can slough off into the peritoneal cavity (between visceral and parietal peritoneum) into fluid which then allows the cancer cells to circulate the peritoneal cavity