Abdomen IV - Peritoneum, Omentum, Epiploic Spaces, Ligaments, Abdominal Viscera & Esophagus Flashcards
Embryology of the Peritoneal Cavity:
“By the end of the 10th week, the gut is much longer than the body that contains it.”
What 2 things are needed for this increase in length to occur?
- gut needs freedom of movement relative to the body wall
- maintain the connection with body wall necessary for innervation and blood supply
The embryological growht of the gut is accomodated by what?
development of the peritoneal serous cavity within the trunk
(houses the increasingly lengthy + convoluted gut in a relatively compact space)
During embryonic growth, why does the gut extend outside of the trunk for a period of time?
rate of growth of the gut initially surpasses the development of adequate space within the trunk
When does the midgut herniate into the umbilical chord?
early in week 5
The primary rotation of the herniated midgut occurs around what structure in the umbilical cord?
superior mesenteric srtery
The herniated midgut returns to the trunk by what time?
by the end of week 10
(by week 11)
During early development, the embryonic body cavity (intraembryonic coelom) is lined with what tissue?
What peritoneal structre is derived from this tissue?
- mesoderm
- the parietal peritoneum is derived from mesoderm
- (forms a closed sac)*
retroperitoneal structures…
…protrude only partially into the peritoneal cavity (partially covered by visceral peritoneum)
Intraperitoneal structures…
…protrude completely into the peritoneal cavity (completely covered by viseral peritoneum)
- connected to abdominal wall by mesentery
In general, viscera that vary relatively little in size and shape are….
retroperitoneal
In general, viscera that undergo changes in size/shape (filling/emptying, peristalsis) are…
invested with visceral peritoneum (intraperitoneal)
- they are mobile to some degree (b/c of mesentaries)
The vessels & nerves of intraperitoneal organs remain connected to what?
their extraperitoneal sources
What major change occurs in regards to the peritoneal cavity space from embryonic development to post-natal life?
changes from the 1. peritoneal cavity
(entire primordial gut is suspended)
to 2. potential space between the parietal + visceral layer
(organs have grown therefore space has been reduced)
As a result of growing organs, several parts of the gut come to lie against the posterior abdominal wall. What does this cause?
- their posterior mesenteries become gradually reduced because of pressure from overlying organs
What happens to the part of the visceral peritoneum lying against the body wall?
fuses with the parietal peritoneum of the body wall
During development, the peritoneal cavity is divided into what sections?
greater and lesser peritoneal sacs
A surgical incision through the anterolateral abdominal wall enters the main, larger part of the peritoneal cavity. Which sac is this?
the greater sac
What sac, also known as the omental bursa, lies posterior to the stomach and lesser omentum?
The lesser sac
The transverse mesocolon (mesentery of the transverse colon) divides the abdominal cavity into what 2 compartments?
What does each compartment contain?
supracolic compartment
- stomach
- liver
- spleen
infracolic compartment
- small intestine
- ascending + descending colon
The infracolic compartment lies posterior to what structure?
It is divided into what 2 spaces by the mesentery of the small intestine?
the greater omentum
- right infracolic space
- left infracolic space
How does free communication occur between the supracolic and the infracolic compartments?
through the paracolic gutters
(grooves between the lateral aspect of ascending or descending colon + posterolateral abdominal wall)
What is the omental bursa?
an extensive sac-like cavity that lies posterior to the stomach, lesser omentum, and adjacent structures
What are the names and locations of the 2 recesses of the omental bursa?
superior recess
limited superiorly by diaphragm + posterior layers of coronary ligament of liver
inferior recess
between superior parts of the layers of greater omentum
What permits free movement of the stomach on the structures posterior and inferior to it?
How does it do this?
The omental bursa
anterior and posterior walls of omental bursa slide smoothly over each other
Most of the inferior recess of the bursa becomes sealed off from the main part posterior to the stomach after what occurs?
adhesion of the anterior + posterior layers of the greater omentum
The omental bursa communicates with the greater peritoneal sac through what structure?
How can this structure be found?
the omental foramen (epiploic foramen)
- opening situated posterior to free edge of lesser omentum (hepatoduodenal ligament)*
- can be located by running a finger along gallbladder to the free edge of the lesser omentum
(usually admits two fingers)
What are the superior, inferior, anterior and posterior borders of the omental foramen?
Superiorly = liver, covered with visceral peritoneum
Inferiorly = superior (first) part of the duodenum
Anteriorly = hepatoduodenal ligament (free edge of the lesser omentum), containing portal vein, hepatic artery, + bile duct
Posteriorly = IVC + right crus of diaphragm (covered anteriorly with parietal peritoneum - retroperitoneal)
What results form a perforation of the posterior wall of the stomach?
passage of its fluid contents into the omental bursa
What pathology can also result in the passage of fluid into the bursa, forming a pancreatic pseudo-cyst?
An inflamed or injured pancreas
What uncommon abnormality may enter the omental bursa and be strangulated by the edges of the foramen?
How is this corrected?
a loop of small intestine may pass through the omental foramen
- swollen intestine must be decompressed using a needle so it can be returned to the greater peritoneal sac through the omental foramen
- (boundaries of the foramen can be incised because each contains blood vessels)*