Part 16: Pelvic Peritoneum, Vessels and Nerves

Question 1

Describe the arrangement of pelvic peritoneum in the male

Answer 1

Draped over pelvic viscera. Anteriorly roofs retropubic space, behind forms the rectovesical pouch with the retroperitoneal tissue forming rectovesical fascia (of Denonvilliers) betwen bladder and rectum. Laterally peritoneum is continuous with that of the side walls

Question 2

How does the pelvic peritoneum differ in the female compared with male?

Answer 2

Largely the same but altered due to presence of uterus and broad ligaments. Thus has vesicouterine pouch and rectouterine pouch (of Douglas).

Question 3

Where does the common iliac artery bifurcate?

Answer 3

At SI joint, IIA passes down and EIA passes more lateral

Question 4

How many branches to anterior division of internal iliac artery?

Answer 4

3 associated with bladder: Superior vesical, inferior vesical, obliterated umbilical
3 associated with other viscera: Middle rectal, uterine artery, vaginal artery
3 parietal: Obturator artery, internal pudendal artery, inferior gluteal artery

Question 5

What are the branches to the posterior division of the internal iliac artery?

Answer 5

Iliolumbar
Lateral sacral artery
Superior gluteal

Question 6

Where does iliolumbar artery arise and where does it supply?

Answer 6

From posterior branch IIA.
Has lumbar branch (essentially the 5th lumbar artery) which supplies psoas, QL, spinal L5 branch
Iliac branch supplies iliac fossa and anastomoses around ASIS

Question 7

Where does lateral sacral artery artery arise and where does it supply?

Answer 7

Arises from posterior branch IIA.

Runs lateral to anterior sacral foramina supplying roots and piriformis. Spinal branches to meninges.

Question 8

Where does superior gluteal artery arise and where does it supply?

Answer 8

Largest branch of IIA - from posterior division.

Exits through greater sciatic foramen above piriformis to supply gluteals

Question 9

Where does superior vesical artery arise and where does it supply?

Answer 9

Highest branch of anterior division of IIA.
Persistent patent proximal part of foetal umbilical artery (distal part becomes medial umbilical ligament). Runs along wall of pelvis, turns medially to reach upper bladder, supplies adjacent ureter and ductus deferens

Question 10

Where does inferior vesical artery arise and where does it supply?

Answer 10

Branch of anterior division of IIA.

Supplies trigone and lower bladder, ureter, ductus deferens and seminal vesicles

Question 11

Where does middle rectal artery arise and where does it supply?

Answer 11

Branch of anterior division if IIA. Maybe absent in females where uterine artery replaces its supply. Supplies lower rectal wall. May give off prostatic artery.

Question 12

Where does uterine artery arise and where does it supply?

Answer 12

Anterior division if IIA.

Crosses pelvis at base of broad ligament superficial to ureter turing up at cervix. Anastomoses with ovarian artery

Question 13

Where does vaginal artery arise and where does it supply?

Answer 13

Anterior division of IIA but often as branch of uterine. Supplies upper vaginal walls.

Question 14

Where does obturator artery arise and where does it supply?

Answer 14

Anterior division of IIA. Passes along side wal of pelvis. Enters OF, branch to pubic symphysis

Question 15

Where does internal pudendal artery arise and where does it supply?

Answer 15

Anterior division of IIA. Lies in front of inferior gluteal, piercing parietal pelvic fascia. Exist through greater sciatic foramen, below piriformis. Supplies perineum and external genitalia.

Question 16

Where does inferior gluteal artery arise and where does it supply?

Answer 16

Anterior division of IIA.

Runs through GSF into buttock below piriformis

Question 17

Describe the pelvic veins

Answer 17

Internal iliac vein is about 3cm long created by confluence of gluteal and other veins. IIV receives blood from various venous plexuses - uterine/vesicoprostatic, rectal
Communicates with vertebral veins via lateral sacral veins. No valves in pelvic veins, therefore blood can be diverted in cases of extreme raised intra-abdominal pressure (eg coughing fit) to aygous veins and drain into SVC

Question 18

Where does the obturator nerve arise?

Answer 18

From lumbar plexus (L2,3,4) - passes down side wall of pelvis to exit via OF

Question 19

Where does the accessory obturator nerve arise?

Answer 19

Lumbar plexus. More similar to femoral nerve in that it is derived from posterior divisions and passes over pubic ramus. Supplies pecitineus when present in 1/3 of individuals

Question 20

The sacral plexus is comprised of what nerves?

Answer 20

Much of L4 and all of L5 form lumbosacral trunk to join anterior rami of 4 sacral nerves

Question 21

Where does sacral plexus lie?

Answer 21

On piriformis muscle

Question 22

What are the branches of the sacral nerves?

Answer 22

6 - start with P
Piriformis twigs
Perforating cutaneous nerve S2,3 (skin over buttock)
Posterior femoral cutaneous nerve (S2,3)
Parasympathetic pelvic splanchnic nerves from rootlets
Pudendal nerve from anterior S2,3,4
Perineal branch of S4 (coccygeus and levator ani and perineal skin)

Question 23

What are the branches from the anterior divisions of plexus?

Answer 23

Nerves to flexor compartments:
Sciatic (tibial part) - L4,5S1,2,3
Nerve to obturator internus
Nerve to quadratus femoris (L4,5,S1)

Question 24

What are the branches from posterior divisions of lumbosacral plexus?

Answer 24

Nerves to extensor compartments:
Sciatic (common peroneal part) (L4,L5,S1,S2)
Superior gluteal nerve (L4,5,S1)
Inferior gluteal nerve (L5,S1,2)

Question 25

What is the inferior hypogastric plexus?

Answer 25

Consists of 2 - right and left, collectively form single pelvic plexus. Autonomic plexus on side wall of pelvis

Question 26

What is the sympathetic and parasympathetic input to IH plexus?

Answer 26

Sympathetic: lumbar and sacral ganglia
Parasympathetic: S2,3,4

Question 27

Parasympathetic nerves from IHP are motor to what organs?

Answer 27

Detrusor muscle of bladder and secretomotor to gut from splenic flexure down

Question 28

Sympathetic nerves from IHP are motor to what organs?

Answer 28

Bladder sphincter
Anal canal sphincter
Ductus deferens
Seminal vesicles
Prostatic muscles
Uterine muscles