Part 3: Peritoneum

Question 1

What is the structure of peritoneum?

Answer 1

single layer of flattened mesothelium cells with overlying areolar tissue

Question 2

How many peritoneal folds are there in the anterior abdominal wall? What are they?

Answer 2

6, 1 above and 5 below umbilicus
1 above: Falciform ligament
below:
1x median umbilical fold - midline, remains of urachus
2x medial umbilical ligament: obliterated umbilical arteries
2x lateral umbilical fold: inferior epigastric vessels

Question 3

What is the falciform ligament?

Answer 3

ligament from umbilicus to xiphisternum. Contains ligamentum teres (remains of L umbilical vein) and enters the fissure of the ligamentum teres on surface of liver

Question 4

What is the greater sac?

Answer 4

Main abdominal cavity

Question 5

What is the lesser sac?

Answer 5

Invagination of greater sac behind the stomach via the epiploic foramen

Question 6

What function does the lesser sac provide?

Answer 6

Allows mobility for posterior surface of stomach by providing potential cavity

Question 7

What are the boundaries of the lesser sac?

Answer 7

Roof - caudate lobe of liver
Anterior wall - lesser omentum and stomach
Left - spleen (lienorenal and gastrosplenic ligaments)
Posterior wall - peritoneum overlying pancreas, L kidney and lower part is made of transverse mesocolon

Question 8

Where does the greater omentum arise?

Answer 8

From greater curvature of stomach, consists of two closely applied layers of peritoneum enclosing blood vessels and lymphatics. Has continuous attachment from oesophagus to duodenum across lower border of stomach

Question 9

Was is the role of the greater omentum

Answer 9

Policeman of abdomen - walls off infection

Question 10

Where does the lesser omentum arise?

Answer 10

Extends between liver and upper border (lesser curvature) of stomach. Attaches to fissure of ligamentum venosum

Question 11

What is the epiploic foramen? What are it’s boundaries?

Answer 11

2.5cm vertical slit between greater and lesser sac
Upper boundary - caudate lobe of liver
Lower boundary - ascending 1st part duodenum
Anterior boundary - R free margin of lesser omentum
Posterior boundary - IVC covered by peritoneum

Question 12

What is within the R free margin of lesser omentum?

Answer 12

portal vein at back
Hepatic artery in front
CBD to front and R of vein

Question 13

The abdomen can be divided into supra and infracolic compartments - what is the division of these compartments?

Answer 13

Transverse mesocolon attachment to posterior wall (over R kidney, duodenum, lower border of pancreas, lower part L kidney

Question 14

What are the divisions of the right and left upper supracolic compartments?

Answer 14

R subphrenic (subdiaphragmatic): Between liver and diaphragm. R falciform makes medial boundary, upper coronary forms posterior boundary
Left subphrenic (subdiaphragmatic): falciform is R boundary, upper coronary makes posterior boundary

Question 15

What are the divisions of the right and left lower supracolic compartments?

Answer 15

Right subhepatic (hepatorenal pouch of Morison): between liver and kidney, bound posteriorly by lower coronary ligament
Left subhepatic region:
Also known as lesser sac

Question 16

The infracolic region is divided into how many compartments by what?

Answer 16

2 compartments - upper(right) and lower(left)

Formed by attachment of mesentary to posterior wall across oblique line from L to R

Question 17

What is the course of the mesenteric root?

Answer 17

Upper left to lower right. Past DJ junction, aorta, IVC, R psoas, R ureter. About 15cm long.

Question 18

What are the boundaries of the right(upper) infracolic compartment?

Answer 18

Apex: Ileocecal junction
R: Ascending colon
L: Attachment of mesentery
Base: transverse mesocolon
Floor: Lower pole R kidney, R colic vessels, 2 part duodenum, DJ flexure

Question 19

What is the R paracolic gutter?

Answer 19

Lies lateral to ascending colon and can be traced from hepatorenal pouch to pelvis - easy pathways for fluid

Question 20

What are the boundaries of left (lower) infracolic compartment?

Answer 20

Upper: Transverse mesocolon
R: Mesentery attachment
L: descending colon
Lower: Attachment of sigmoid colon
Floor: 4th part of duodenum, inferior pole L kidney, sigmoid colon, L ureter near apex

Question 21

Describe the L para-colic gutter

Answer 21

Lateral to descending colon. Limited by the phrenicocolic ligament between diaphragm and colon at splenic flexure. This helps prevent upward spread of infection on L side