Peritoneum and Retroperitoneum Flashcards
What structure separates the peritoneum from the retroperitoneum?
Peritoneal membrane
Describe the peritoneum
Thin layer of loose connective tissue which lines the abdominal cavity
What does the peritoneum produce?
Serous fluid
What does the peritoneum contain?
Fat (provides padding and support), blood vessels, lymphatics and nerves
Why does the peritoneum create ligaments and folds?
To anchor the organs
How does the peritoneum allow for free movement b/w the organs?
Serous fluid
What are the 2 layers of the peritoneum?
Parietal and Visceral
What does the parietal and visceral cavity create?
Potential space/cavity
What happens to the peritoneal membrane as structures move into the abdominal cavity from the posterior abdominal wall?
Moves anterior
What are the organs that become enclosed with double folds of peritoneum called?
Intraperitoneal organs
What are the organs that only have their anterior surfaces covered with peritoneal membrane called?
Retroperitoneum organs
Define mesentery
Peritoneal folds connecting the small and large bowel to the posterior abdominal wall
How is the mesentery shaped?
Large and fan shaped
Define mesocolon
Peritoneum attached to the colon
What does the mesocolon connect?
Connects the transverse colon and sigmoid to the posterior abdominal wall
Define lesser omentum
Double layer of mesentery
What does the lesser omentum connect?
Connects the lesser curve of the stomach and the 1st part of the duodenum to the visceral surface of the liver
Define greater omentum
Apron like fold
What does the greater omentum connect?
Connects the greater curvature of the stomach to the transverse colon
What is a ligament?
Double fold of peritoneum that connects one organ to another
How are ligaments named?
Names based on the organs they are attached to
What runs within a ligament?
Blood, lymphatic vessels and nerves to organs
Where is the falciform ligament located?
Passes over the anterior superior surface of the liver and splits
Where does the falciform ligament travel?
From the umbilicus to the liver
What structure runs through the falciform ligament?
Ligamentum teres
What other ligaments are formed by the splitting of the falciform ligament?
- Triangular ligament
2. Coronary ligament
What makes the coronary ligaments?
Made of parietal peritoneum
Where are the coronary ligaments located?
On the posterior aspect of the liver
What do the coronary ligaments define?
“Bare area” on the liver
What makes up the ligamentum teres?
Remanent of the fetal umbilical cord
Where does the ligamentum teres travel?
Runs in the falciform ligament and joins the LPV at the port hepatis
What is the ligamentum venosum?
Remnant of the fetal ductus venosum
What does the ligamentum venosum attach to?
Attaches to the LPV above the IVC
What are the triangular ligaments?
“Corner” of the bare area
What do the hepatoduodenal ligament conduct?
Conducts the MPV, CBD and HA
What are other ligaments that run within the peritoneal cavity?
Hepatogastric
Gastrocolic
Gastrosplenic
Splenorenal (lienorenal)
Is the peritoneal sac a closed sac?
Not in females (due to fallopian tubes)
What is another name for the right sub hepatic space?
Morison’s pouch
What structures is the morison’s pouch posterior to?
Right lobe of the liver and GB
What structures is the morison’s pouch anterior to?
Upper pole of the right kidney
What is the morison’s pouch posteriorly bound by?
The upper pole of the right kidney and diaphragm
What does the right boundary of the morison’s pouch consist of?
Right lobe of the liver and diaphragm
What lies interiorly to the morison’s pouch?
2nd part of the duodenum
What is to the left of the morison’s pouch
Epiploic foramen of Windslow
What is the most dependent portion of the subhepatic space?
Morison’s pouch
Is the lesser sac part of the right or left subhepatic space?
Left subhepatic space
What is contained within the left subhepatic space?
Anterior and posterior recesses
Describe the subphrenic space
Anterior and posterior portions
What does the posterior right subphrenic space communicate with?
Right subhepatic space
What structure defines the subphrenic space?
Liver and diaphragm
What ligament divides the subphrenic space into right and left?
Falciform ligament
Does the lesser sac communicate with the greater sac?
Yes
What is the alternate name for the lesser sac?
Omental bursa
What are the 3 terms for the opening of the lesser sac?
- Epiploic foramen
- Foramen of Winslow
- Omental foramen/neck
What structure lies posterior to the opening of the lesser sac?
IVC
What structure lies superior to the opening of the lesser sac?
Caudate lobe
What structure lies directly anterior to the lesser sac?
Stomach
What retroperitoneal structure lies directly posterior to the lesser sac?
Pancreas
Which sac accounts for the most space in the peritoneal cavity?
Greater sac
What is the relation of the greater sac to the lesser sac?
Anterior to the lesser sac superiorly
Posterior to the lesser sac inferiorly
What structure divides the greater sac to into supramesocolic and inframesocolic compartments?
Transverse mesocolon
What structure are included in the Supramesocolon space?
Subphrenic and subhepatic spaces
What structures are included in the Inframesocolic space?
Paracolic gutters and pelvic reflections
What structure divides the inframesocolic into right and left compartments?
Root of mesentery
The right and left inframesocolic compartments are further divided into medial and lateral compartments by what structures?
The ascending colon (right)
The descending colon (left)
What is the right paracolic gutter?
Space b/w the ascending colon and the right lateral abdomen wall
What is the left paracolic gutter?
Space b/w the descending colon and the left lateral abdomen wall
Which portion of the inframesocolic compartment does not communicate with the pelvic cavity directly?
Right medial compartment because the root of the mesentery blocks any fluid
Which ligament prevents the left lateral gutter from communicating with the left supramesocolic area?
Phrenocolic ligament
What is the appearance of the parietal peritoneum?
Thin smooth echogenic line deep to the abdominal wall muscles- peritoneal line
What is the scanning technique used for the peritoneum and retroperitoneum?
- Should fast overnight to reduce bowel gas
- 3.5 to 5 MHz probe
- Pt scanned in supine
- Apply graded compression
When is the mesentery viewed on US?
When there is ascitis in the abdomen- appears as a free floating smooth leaves directed towards the centre of the abdomen
The retroperitoneum is posterior to what structure?
Peritoneum
The retroperitoneum is anterior to what structure?
Transversalis fascia
What forms the inferior boundary of the retroperitoneum?
Pelvic brim (pelvic diaphragm)
How many compartments/spaces make up the retroperitoneum?
3
How many layers of fascia is the retroperitoneum made of?
2
What structures define the boundary of the anterior pararenal space?
Anterior- gerotas fascia
Posterior- peritoneum
What are the major structures within the anterior pararenal space?
Ascending and descending colon, duodenum (besides the first part) and the pancreas
Does the anterior pararenal space potentially communicate with the posterior pararenal space and pelvis?
Yes - potential midline communication
What structures enclose the perirenal space?
Renal fascia or gerotas fascia
What are the major structures within the perirenal space?
Kidneys, adrenals, ureters and great vessels
Does the perirenal space communicate with the pelvic area?
No- no communication across midline due to the great vessels blocking flow
Describe the posterior pararenal space
- Extends from the posterior renal fascia anteriorly to the transversalis fascia
- No solid organs
- Contains fat
What are the 3 spaces that communicate with the posterior pararenal space?
- Anterior pararenal space
- Pelvis
- Peritoneal space- potential space b/w peritoneum and transversalis fascia
What is the role of US when examining the peritoneum and retroperitoneum?
- Characterize lesions
- Assess aortic aneurysms
- Provide guidance for interventional procedures
