Peritoneum and Reflections

Question 1

What is the superior boundary of the abdominal cavity?

Answer 1

Thoracic diaphragm

Question 2

What is the inferior boundary of the abdominal cavity?

Answer 2

Continuous with pelvic cavity

Question 3

What are anterior and lateral boundaries of the abdominal cavity?

Answer 3

Abdominal muscles

Question 4

What is the posterior boundary to the abdominal cavity?

Answer 4

Lumbar vertebrae

Question 5

Is there a structure separating between the abdominal and pelvic cavity?

Answer 5

No - one big cavity (peritoneum goes into pelvis)

Question 6

What does the ileum empty into?

Answer 6

1st bit of the colon called the cecum

Question 7

4 parts of the colon

Answer 7

Ascending, transverse, descending, sigmoid

Question 8

What does the sigmoid colon join to?

Answer 8

Rectum

Question 9

Where does the foregut extend to/from?

Answer 9

Oesophagus to middle duodenum

Question 10

Where does the midgut extend to/from?

Answer 10

Middle duodenum to 2/3rds transverse colon

Question 11

Where does the handout extend to/from?

Answer 11

2/3rds transverse colon to anus

Question 12

What does retroperitoneal mean?

Answer 12

Situated outside the peritoneum, in contact with body wall (but intra-abdominally) eg. kidneys (only covered on one side)

Question 13

Are the kidneys intra or retroperitoneal?

Answer 13

Retroperitoneal (between posterior body wall and peritoneum)

Question 14

What does intraperitoneal mean?

Answer 14

Suspended from the abdominal wall by a double layered fold of peritoneum. Completely covered by peritoneum on both sides

Question 15

Are the small intestines intra or retroperitoneal?

Answer 15

Intraperitoneal (suspended in peritoneal sac via mesentery)

Question 16

What is the mesentery?

Answer 16

• Double layered fold of peritoneum. - Route for nerves, blood vessels, lymphatics.

Question 17

Where does blood supply to the foregut come from?

Answer 17

Coeliac trunk (single branch of aorta)

Question 18

Where does blood supply to the midgut come from?

Answer 18

Superior mesenteric artery (branch of aorta)

Question 19

Where does blood supply to the hindgut come from?

Answer 19

Inferior mesenteric artery (branch of aorta)

Question 20

During development the whole gut tube has a dorsal mesentery. What does this provide?

Answer 20

• An attachment to the posterior wall
• Separates gut tube from body wall, allowing it to grow longer than body cavity
• Aorta, IVC, spinal cord, sympathetic chain all dorsal
  
  • E.g. important for dorsal with aorta so can get blood vessel to that part of gut tube

Question 21

What does the mesentery of the small intestine attach it to?

Answer 21

The posterior body wall

Question 22

How is the transverse colon attached to the posterior wall?

Answer 22

Transverse mesocolon

Question 23

What separates the peritoneal cavity into supracolic and infracolic compartments?

Answer 23

The mesocolic shelf

Question 24

What does rotation of the SI during development cause?

Answer 24

• Pushes part of tube against posterior wall
• Loses primitive dorsal mesentery –> not completely invested so is secondarily retroperitoneal (as started intraperitoneal)

Question 25

What regions of the gut are secondary retroperitoneal?

Answer 25

Ascending and descending colon

Question 27

What are paracolic gutters?

Answer 27

Grooves either side of tube (important in infection)

Question 28

Where is the lesser sac of the peritoneal cavity?

Answer 28

Recess of peritoneal cavity behind stomach

Question 29

What is the greater sac of the peritoneal cavity?

Answer 29

Main peritoneal cavity. This, in turn, is subdivided into supracolic and infracolic compartments.

Question 30

How are the greater and lesser sacs linked?

Answer 30

Epipoloic foramen

Question 31

How is the GI tract connected to the posterior wall?

Answer 31

Dorsal mesentery

Question 32

Where is the ventral msenery (attachment to ventral surface)

Answer 32

Level of the foregut only

Question 33

Before stomach rotates, what organs develop in dorsal/ventral mesentery?

Answer 33

Ventral –> liver (anterior)

Dorsal –> spleen (posterior)

Question 34

Due to development of organ in ventral mesentery what happens?

Answer 34

Split into 2 parts:

• Part that goes from gut tube to liver (lesser omentum)
• Part that goes from liver to anterior wall (falciform ligament)

Question 35

Due to development of organ in dorsal mesentery, what happens?

Answer 35

Split into 2 parts:

1. Between spleen and kidney –> Lienorenal ligament (splenorenal ligament)
2. Gastrosplenic ligament

Question 36

How does the stomach rotate?

Answer 36

90 degrees clockwise

Question 37

As the stomach rotates, what happens?

Answer 37

The liver is pushed to the right hand side

The spleen is pulled around to the left hand side

Lesser sac pulled behind stomach

Greater sac pulled anterior to stomach

Question 38

What happens to the dorsal mesentery in order for this rotation to occur?

Answer 38

Increases in size so rapidly it folds back on itself to attach to posterior wall

Question 39

Mesentery hanging from stomach:

Answer 39

Attaches to dorsal aspect –> greater omentum

Attaches to liver from ventral mesentery –> less omentum

Question 40

Where is the lesser omentum?

Answer 40

Between lesser curvature of stomach to liver

Question 41

Where is the falciform ligament?

Answer 41

From liver to anterior wall

Question 42

Where do the lesser omentum and falciform ligament arise from?

Answer 42

Ventral mesentery

Question 43

Where does greater omentum arise from?

Answer 43

From dorsal mesentery, folds back on itself and attaches to posterior wall

Question 44

How can infection spread around the abdomen?

Answer 44

Epiploic foramen

Question 45

What can the greater sac be subdivided into?

Answer 45

The supracolic and infracolic compartments. These are both within the greater sac but located above and below the transverse colon when pulled anteriorly.

Question 46

What are the features of the infracolic compartment?

Answer 46

• Paracolic gutters
• The mesentery