1-5 Abdominal Organization and Peritoneum

Question 1

What are the lines that are used to divide the surface abdomen into 9 parts? What’s the orientation?

Answer 1

Vertical - 2 midclavicular lines

Horizontal -
subcostal line - inferior to 10th rib
transtubercular line - passes through tubercles of iliac crests

Question 2

What is the orientation of the lines that divide the surface of the abdomen into quadrants?

Answer 2

2 perpendicular lines which intersect at the umbilicus

Question 3

What are the limits of the abdominopelvic cavity?

Answer 3

Thoracoabdominal diaphragm (superior)
(pelvic brim in between)
Pelvic diaphragm (inferior)

Question 4

What are the connective in the abdominopelvic cavity? (superficial to deep)

Answer 4

1. Transversalis fascia
2. Extraperitoneal connective tissue
3. Peritoneum

Question 5

What does transversalis fascia line?

Answer 5

Entire abdominopelvic cavity - doesn’t extend into mesenteries

Question 6

What attaches viscera to posterior abdominal wall?

Answer 6

Mesenteries

Question 7

What does extraperitoneal connective tissue line? What is the tissue made up of?

Answer 7

Underlies all visceral peritoneum - AKA subserous fascia

Loose areolar and fatty layer
- between transversalis fascia and parietal peritoneum

Question 8

What does the peritoneum line? What does it support?

Answer 8

A mesothelial layer (simple squamous epithelium of mesodermal origin)

lines the abdominopelvic cavity (parietal)

covers the organs suspended within it and forms all mesenteries (visceral)

Question 9

What is the serosa in the peritoneum? Where is it secreted, and what is it’s purpose?

Answer 9

Mesothelium along with an accompanying layer of submesothelial connective tissue form a serosa which secretes a thin, watery fluid (serous fluid) that reduces friction between opposing peritoneal surfaces

Question 10

Is the peritoneum an open or closed sac?

Answer 10

Closed - the abdominal organs are pushed into it and suspended

Question 11

What is the area within the peritoneal sac? What are the contents?

Answer 11

The area within the peritoneal sac is referred to as the peritoneal cavity and its only normal content is serous fluid.

Question 12

In what cavity are abdominal organs housed?

Answer 12

abdominal cavity

Question 13

How is the peritoneal cavity divided?

Answer 13

greater and lesser peritoneal sac

Question 14

What does the greater sac of the peritoneum include?

Answer 14

The greater sac includes all areas within the peritoneal cavity except the area housed within the omental bursa

Question 15

What are mesenteries? What is another name for them? What do they often contain?

Answer 15

Mesenteries are duplications of peritoneum which are reflected against one another (two layers) as parietal peritoneum transitions into visceral peritoneum

often referred to as peritoneal ligaments

possess a core of extraperitoneal CT in which vessels, nerves and lymphatics course to and from organs

Question 16

What are peritonealized or intraperitoneal organs?

Answer 16

Organs covered and suspended by a mesentery

Question 17

What are organs that are covered by peritoneum on one surface?

Answer 17

retroperitoneal, extraperitoneal or subperitoneal

Question 18

How are retroperitoneal organs suspended?

Answer 18

Retroperitoneal structures are affixed directly to the posterior abdominal wall and are not suspended by a mesentery

Question 19

What are primary retroperitoneal organs?

Answer 19

Primarily retroperitoneal are organs which originally developed in a retroperitoneal position, i.e. kidney

Question 20

What are secondary retroperitoneal organs? What are some secondary retroperitoneal organs?

Answer 20

Secondarily retroperitoneal are organs which were originally peritonealized, but upon fixation to the posterior body wall during development, became retroperitoneal

Includes: duodenum, ascending and descending colon

Question 21

How is the abdominopelvic cavity compartmentalized in a general sense? What divides it?

Answer 21

The abdominopelvic peritoneal cavity is divided transversely at the level of the transverse colon into supracolic and infracolic compartments by the passage of the transverse mesocolon

Question 22

Where is the infracolic compartment?

Answer 22

Peritonealized area directly inferior to the transverse colon and its associated mesocolon

Question 23

What does the infracolic compartment house?

Answer 23

small intestine

Question 24

What divides the infracolic compartment?

Answer 24

Subdivided into right and left infracolic compartments by the passage of the mesentery proper

Question 25

What are the boundaries of the right infracolic compartment?

Answer 25

Superior: Transverse colon and its mesocolon Right: Ascending colon Left: Right side of the root of the mesentery Inferiorly: Root of the mesentery and cecum

Question 26

What are the boundaries of the left infracolic compartment?

Answer 26

Superior: Transverse colon and its mesocolon Right: Left side of the root of the mesentery Left: Descending colon Inferior: Sigmoid colon

Question 27

What are the paracolic gutters? Where are they located?

Answer 27

Paired, right and left areas of the infracolic compartment which exist lateral to the ascending and descending colon

Question 28

What does the right paracolic gutter communicate with?

Answer 28

communicates above with the hepatorenal recess and the pelvic peritoneal cavity below

Question 29

What does the left paracolic gutter communicate with?

Answer 29

closed superiorly by the phrenicocolic ligament and opens inferiorly to the pelvic peritoneal cavity

Question 30

Where is the supracolic compartment?

Answer 30

Peritonealized area between the thoracoabdominal diaphragm and the transverse colon and its associated mesocolon

Question 31

What are the contents of the supracolic compartment?

Answer 31

Contains the stomach, spleen, liver, gall bladder, and part one of the duodenum

Question 32

What further subdivides the supracolic compartment?

Answer 32

Further subdivided by the lesser omentum thereby forming the omental bursa

Question 33

What is the dorsal mesentary, in a functional sense?

Answer 33

Attachments of the gut to the posterior body wall

Question 34

What is the greater omentum? What is it an extension of?

Answer 34

Extension of dorsal mesentery from the greater curvature of the stomach and proximal duodenum

Question 35

Where is the greater omentum located? What does it cover and what does it become?

Answer 35

Extends anteriorly over the small intestine, loops back to the transverse colon where it fuses with itself to form the gastrocolic ligament

Question 36

What is the gastrocolic ligament made out of?

Answer 36

Greater omentum

Question 37

What does the greater omentum house?

Answer 37

Houses the inferior recess of the lesser peritoneal sac

Question 38

What 5 ligaments arise from the mesentery?

Answer 38

``` Gastrophrenic ligament Gastrosplenic ligament Phrenicosplenic ligament Splenorenal ligament Phrenicocolic ligament ```

Question 39

What does the gastrophrenic ligament connect?

Answer 39

fundus of stomach to diaphragm

Question 40

What does the gastrosplenic ligament connect?

Answer 40

greater curvature of stomach to spleen

Question 41

What does the phrenicosplenic ligament connect?

Answer 41

diaphragm to superolateral portion of the spleen

Question 42

What does the splenorenal ligament connect?

Answer 42

hilum of spleen to superior pole of left kidney

Question 43

What does the phrenicocolic ligament connect? What does it do?

Answer 43

from diaphragm to the left colic flexure Supports the spleen Prevents ascites from entering the supracolic compartment via the left paracolic gutter

Question 44

What does the mesentery proper attach to?

Answer 44

posterior abdominal wall to the jejunum and ileum along a line from the re-entry point of the duodenum into the peritoneal cavity to the cecum

Question 45

Where is the supraduodenal fold? What does it house?

Answer 45

located above the duodenojejunal flexure houses the supraduodenal fossae posterior to it that is entered from below

Question 46

What is the infraduodenal fold? What does it house?

Answer 46

located below duodenojejunal flexure houses the infraduodenal fossa which is entered from above

Question 47

What is the retroduodenal fossa? Where is it?

Answer 47

peritoneal recess located dorsal to part 4 of the duodenum as it re-peritonealizes

Question 48

Where is the paraduodenal fold? What is near it? What does it house?

Answer 48

located to the left of the duodenum raised by the underlying inferior mesenteric vein houses the paraduodenal fossa

Question 49

What does the mesoappendix attach to?

Answer 49

posterior abdominal wall to vermiform appendix

Question 50

What does the mesoappendix attach to?

Answer 50

posterior abdominal wall to vermiform appendix

Question 51

What does the transverse mesocolon attach to?

Answer 51

posterior abdominal wall to transverse colon

Question 52

What does the sigmoid mesocolon attach to?

Answer 52

posterior abdominopelvic area to sigmoid colon

Question 53

What structures are part of the ventral mesentery?

Answer 53

``` Lesser omentum Omental bursa Falciform ligament Coronary ligaments Triangular ligaments ```

Question 54

What structures are part of the ventral mesentery?

Answer 54

Lesser omentum Omental bursa Falciform ligament

Question 55

Where is the lesser omentum?

Answer 55

extends from the lesser curvature of the stomach and duodenum to the hilum of the liver (porta hepatis)

Question 56

How is the lesser omentum divided?

Answer 56

(1) Hepatogastric ligament | (2) Hepatoduodenal ligament

Question 57

What travels near the hepatoduodenal ligament?

Answer 57

The proper hepatic artery, portal vein and common bile duct travel within the extreme right edge of the hepatoduodenal ligament

Question 58

Where is the omental bursa located?

Answer 58

Located posterior to the lesser omentum

Question 59

What is an important landmark associated with the omental bursa?

Answer 59

Epiploic foramen (Winslow) entrance to the omental bursa

Question 60

What are the boundaries of the omental bursa?

Answer 60

Anterior: Hepatoduodenal ligament Superior: Visceral surface of the liver Posterior: IVC and right crus of the diaphragm Inferior: Part one of the duodenum

Question 61

What is the falciform ligament? What does it house - or what did it used to house?

Answer 61

Ventral attachment of the liver to the body wall | houses the ligamentum teres hepatitis (obliterated umbilical vein) within its inferior edge

Question 62

What is the embryological importance of the peritoneum that surrounds the liver?

Answer 62

The liver develops within the ventral mesogastrium | The peritoneum that envelops the liver in the adult is of ventral origin

Question 63

What are the coronary ligaments?

Answer 63

Peritoneum which attaches the superior surface of the liver to the abdominal surfaces of the diaphragm (divisible into anterior, posterior, left and right) Encircles the superior portion of the liver like a crown, hence coronary. Think: coronation

Question 64

What are the triangular ligaments?

Answer 64

where anterior and posterior coronary ligaments meet they form right and left triangular ligaments, respectively

Question 65

Does the liver have an area that isn't peritonealized?

Answer 65

Yes - the bare area of the liver Left and right anterior and posterior coronary ligaments meet only laterally relative to the liver forming the triangular ligaments, the area between lies in direct contact with the visceral surface of the diaphragm