Lecture 22: Vessels, Nerves & Lymphatics of Pelvis

Question 1

What is the major artery going to the pelvis?

Answer 1

Internal iliac

Question 2

What are the arterial branches coming from outside of the pelvis?

Answer 2

Ovarian/testicular: direct branch of abdominal aorta just below renal artery
Superior rectal: branch of inferior mesenteric to sigmoid colon and upper rectum
Median sacral

Question 3

What are the posterior artery branches?

Answer 3

Iliolumbar, lateral sacral, superior gluteal

Question 4

What are the anterior artery branches?

Answer 4

Obturator, inferior gluteal, internal pudendal

Question 5

What does the internal pudendal artery give off?

Answer 5

Inferior rectal artery

Question 6

What arteries in the female pelvis anastomose extensively?

Answer 6

Uterine and vaginal arteries

Question 7

What is characteristic of the uterine artery?

Answer 7

Tortuous course - coiled to allow for expansion of the uterus in pregnancy

Question 8

What is the arterial supply to the rectum and anal canal above the pectinate line?

Answer 8

Superior rectal artery

Question 9

What is the arterial supply to the rectum and anal canal below the pectinate line?

Answer 9

Middle and inferior rectal arteries

Question 10

What are the features of end organs (blood supply)?

Answer 10

Supplied by end arteries - do not apply vasoconstrictors to these areas ) fingers, toes, nose, penis)

Question 11

What are the large visceral venous plexuses in the pelvis?

Answer 11

Vesical, prostatic, uterovaginal, rectal

Question 12

Where do veins in the pelvis drain and what does this communicate with?

Answer 12

Tributaries of the internal iliac vein - communicates with internal vertebral venous plexus

Question 13

What is the consequence of vein communication?

Answer 13

Spread of infection and cancer

Question 14

Where does the prostatic venous plexus normally drain?

Answer 14

IVC

Question 15

What happens when there is retrograde drainage of the prostatic venous plexus?

Answer 15

Drain via anterior sacral veins - spread of cancer into vertebral canal (more common in bone)

Question 16

How is erection maintained?

Answer 16

Cavernous tissue engorged with blood - compressed veins, preventing venous return

Question 17

Where does the superior rectal vein drain?

Answer 17

Portal venous system via inferior mesenteric

Question 18

What happens due to the portosystemic anastomoses between rectal veins?

Answer 18

Superior (portal) and middle and inferior (systemic) - elevation of venous pressure, varies, haemorrhage

Question 19

What do haemorrhoids in the upper anal canal lead to?

Answer 19

Discomfort

Question 20

What do haemorrhoids in the lower anal canal lead to?

Answer 20

Pain

Question 21

Where does pelvic viscera lymph drain to?

Answer 21

Directly to deep nodes (inguinal)

Question 22

What is the lymph drainage of the testes and what problems does this cause?

Answer 22

Drain to lymph nodes on posterior ab wall, not palpable, cancer not detected until supraclavicular nodes (last sentinel nodes)

Question 23

What is the lymph drainage for the sacrum?

Answer 23

Develops from anterior ab wall so drains to inguinal lymph nodes

Question 24

What are the spinal segments of the sacral plexus?

Answer 24

S2,3,4

Question 25

What are the main parietal branches of the sacral plexus?

Answer 25

Obturator and pudendal nerves

Question 26

What is the pathway of the pudendal nerve?

Answer 26

S2, 3, 4, makes a brief appearance in pelvic cavity via GSF then immediately exits via LSF to supply pelvic floor from below

Question 27

Why doesn’t a pudendal nerve block paralyse the pelvic floor?

Answer 27

Pelvic floor branches given off early, not affected by block

Question 28

What does the superior hypogastric plexus do?

Answer 28

Sympathetic - contract sphincters and constrict arteries

Question 29

What do the pelvic splanchnic nerves do?

Answer 29

Parasympathetic - cavernous nerves to smooth muscle in walls of viscera

Question 30

What nerves does the inferior hypogastric plexus carry and where is it?

Answer 30

Mixed - adjacent to viscera

Question 31

What are junctional zones in the perineum?

Answer 31

Where endodermal and ectodermal structures form an interface. Sites of overlap of vessels supply and drainage. Blood vessels overlap but there is a non-overlap between nerves

Question 32

How does defeacation occur?

Answer 32

Faeces collects in lower anal canal, stretch stimulates afferent fibres (PNS), stimulates contraction of rectal wall – inhibit SNS – relax internal anal sphincter, pudendal nerve voluntarily relaxes external sphincters

Question 33

How does erection occur

Answer 33

Parasympathetic stimulation – dorsal artery dilation, compression of veins (restricted venous drainage), erection PNS, ejaculation SNS

Question 34

What types of autonomics do pain fibres pass with above and below the pelvic pain line?

Answer 34

Above pelvic pain line visceral afferent pain fibres pass with sympathetics (T1-L2), and below pain fibres pass with parasympathetics (S2-4)

Question 35

Where is the trigone in relation to the pelvic pain line and where is pain referred?

Answer 35

Below - pain referred to penis/clitoris or perineum