14. Peritoneum Flashcards
Describe the peritoneum.
What is created between the two layers?
Thin, single-celled layer of mesothelium that covers the internal surfaces of the abdominal wall (and some organs on the posterior abdominal wall (parietal peritoneum)), and envelopes abdominal viscera (visceral peritoneum).
Potential space (peritoneal cavity) containing small amount of serous fluid (peritoneal fluid) - allows movement.
What does retroperitoneal mean (give examples)?
What does intraperitoneal mean (give examples)?
Organs behind peritoneum e.g. duodenum, ascending and descending colon, rectum, pancreas. These organs can move against each other.
Remain surrounded by peritoneal cavity e.g. liver, stomach, ileum, jejunum, caecum, transverse colon, sigmoid colon, spleen. Also mesentry (in small intestine - tissues formed by double fold of peritoneum), lesser and greater omentum (stomach), ligaments (e.g. gastrosplenic), mesocolon (e.g. transverse mesocolon)
3 distinct parts of the gut tube develop. Describe the 3 including what they contain and their blood supply.
Where is the division between the first 2 parts?
Where is the division between the last 2 parts?
1) Foregut: stomach, 1st part of duodenum, liver, pancreas, spleen. Coeliac trunk.
2) Midgut: Caudal duodenum (jejunum, ileum, caecum), small and large intestine up to splenic flexure. Superior mesenteric artery.
3) Hindgut: Splenic flexure, descending and sigmoid colon, rectum, upper anal canal. Inferior mesenteric artery.
Where biliary tree empties into duodenum
Close to splenic flexure - 2/3 way along transverse colon
Describe the beginning of the development of the foregut.
How is the first development step of the foregut different from the midgut and hindgut?
One tube passing through abdomen. It is attached to the front wall via ventral mesogastrium, and to the back wall via the dorsal mesogastrium. Then the liver develops in the VM, and spleen and pancreas develop in the DM. The liver grows and migrates to the R which pushes stomach to L and causes it to rotate - greater and lesser curvature begin to develop.
Midgut and hindgut only have attachements to posterior abdominal wall; foregut attaches to posterior and anterior.
What is the lesser sac/omental bursa?
What is the falciform ligament?
What is the:
a) omentum
b) greater omentum
c) lesser omentum
Small abdominal cavity behind the stomach, formed by lesser and greater omentum.
Double fold of peritoneum, extends from anterior abdominal wall to the liver. (Peritoneal ligaments formed from double layers of peritoneal membrane connecting an organ with another organ or abdominal wall)
a) double-layered segment of peritoneum that connects the stomach to other organs (in contrast to mesentry which connects viscera to abdominal wall).
b) from greater curvature of stomach and proximal duodenum, large flap of tissue hanging like apron, passes back and merges with transverse colon. Large flap of loose CT and fat. V. vascular(gastroepiploic arteries) and lots oflymphocytes
c) between lesser curvature of the stomach and proximal duodenum, and liver. Runs as 2 peritoneal ligaments: hepatogastric (liver to stomach) and hepatoduodenal (liver to duodenum) ligament
How are the midgut and hindgut attached to the posterior abdominal wall?
Are the lesser and greater sacs continous?
What is the epiploic foramen?
Breifly describe how the midgut forms.
By dorsal mesentry.
Yes
Entrance to lesser sac (from greater sac)
Forms U-shaped intestinal loop which herniates into umbilical cord (wk 6). Inadequate room in abdomen - rotates 900. Returns to abdomen (wk 10) and rotates another 1800. (2700 overall)
What is omphalocele?
What is:
a) supracolic compartment
b) infracolic compartment
One of most common congenital abnormalities. Failure of central fusion at the umbilical ring causing incomplete closure of the abdominal wall and persistant herniation of midgut.
a) Greater sac is divided into 2 compartments by mesentery of transverse colon: supracolic compartment lies above the transverse mesocolon and contains the stomach, liver and spleen
b) Infracolic compartment lies below the transverse mesocolon and contains the small intestine, ascending and descending colon. The infracolic compartment is further divided into L and R infracolic spaces by the mesentery of the small intestine
The supracolic and infracolic compartments are connected by the paracolic gutters which lie between the posterolateral abdominal wall and the lateral aspect of the ascending or descending colon.
Label A-F.
What is the blue area?
What is the green area?
What is the orange area?
A: lesser omentum
B: falciform ligament
C: stomach
D: greater omentum
E: visceral peritoneum
F: parietal peritoneum
Blue: lesser sac
Green: supracolic of greater sac
Orange: infracolic of greater sac
What does the falciform ligament contain?
The ligamentum teres - remains of L umbilical vein (pic) (blood supply comes through ligaments to organs)
What is this?
Lesser omentum - from inferior liver to lesser curvature of the stomach
What structures are found in the free border of the lesser omentum?
How is blood supply to the liver divided up between these structures?
The ‘portal triad’ are in the hepatoduodenal ligament: hepatic artery proper, bile duct, hepatic portal vein
75% from hepatic portal vein, 25% from hepatic artery proper. Both travel through free border of lesser omentum.
What are the following indicating (and state where they go to and from):
a) green arrow
b) blue arrow
c) pink arrow
a) Greater omentum - from stomach (greater curvature) to transverse colon
b) Transverse mesocolon - from transverse colon to posterior body wall
c) Mesentary - from small intestine to posterior body body wall
What does the mesentery do?
What is ascites?
How are most abdominal proceedures performed?
Are retroperitoneal or intraperitoneal organs most static?
Anchors small intestine and provides pathway for blood supply (superior mesenteric artery)
Build up of peritoneal fluid in peritoneal cavity, could be air (pneumoperitoneum) or blood (hemoperitoneum), or due to liver failure.
Insufflation during laproscopy (pump air into peritoneal cavity)
Retroperitoneal
NB: also peritoneal dialysis can be used for those with kidney failure
What are peritoneal recesses?
Why are they clinically significant?
Where peritoneum folds -> pouch-like recesses formed. Subphrenic recesses. Hepatorenal recess.
Potential spaces that may become filled with blood/pus/inflammatory fluid. Hepatorenal recess most likely to accumulate blood if lying down. One of the first places to look in trauma via FAST scan.
Label the subdivisions of the peritoneal cavity.
a) supracolic compartment (contains stomach, liver, spleen)
b) infracolic compartment (contains small intesting, ascending and descending colon)
c) R infracolic gutter
d) L infracolic gutter
* Fluid passes through greater sac if someone is standing - fluid drains down through peritoneal cavity towards pelvis.*
