GI Section II: Peritoneal Cavity Flashcards
What is the peritoneal cavity?
The peritoneal cavity is the space between the various coverings (parietal and visceral peritoneum) in the abdomen. It can be both a conduit for disease and a source of anatomic trivia.
What are the two primary “sacs” of the peritoneal cavity?
Greater and Lesser
The “sac” behind the stomach
Lesser sac
Lesser sac is a.k.a.?
Omental bursa
What is the conduit (channel) between the Greater and LEsser sac?
Epiploic foramen (of Winslow)
The greater sac can be divided into parts:
Above (supracolic)
——– TRANSVERSE MESOCOLON —-
Below (infracolic)
supracolic and infracolic compartments are connected by these
The right and left paracolic gutters along the lateral aspects of the ascending and descending colon
Which paracolic gutter is wider?
the right one
How does the femal peritenoeum communicate with the extraperitoneal pelvis?
Via the fallopian tubes
(male peritoneum does not communicate)
Barium in HSG =
peritonitis
Disease may spread through the abdomen and pelvis by
(1) the bloodstream
(2) Lymphatic extension
(3) Direct invasion
(4) Intraperitoneal seeding
allows spread from the stomach, esophagus, and liver
Gastrohepatic Ligament
allows spread from the stomach to the splenic hilum
Gastrosplenic Ligament
allows spread from the right colon to nodes around the duodenum / pancreas
Duodenocolic Ligament
occurs from spread along the peritoneal ligaments and mesenteries
(2) Lymphatic extension / (3) Direct invasion
this occurs via the natural flow of fluid
Intraperitoneal seeding
The natural intraperitoneal fluid mostly flows upward from the pelvis to the upper abdomen via
The right (more than left) paracolic gutters
Anywhere the fluid tends to spend more time / get caught up (shown by the stars) will be predisposed for serosal-based metastases in the setting o f peritoneal carcinomatosis.
Pus and ascites tends to flow away from the liver (the opposite of normal flow). As a result the dependent areas
right posterior subphrenic recess (RPSA)
anterior subheptic space (ASH)
posterior sub hepatic space / hepatorenal recess / Morrison (M) and pelvic cavity
tend to be involved.
This is a gelatinous ascites
Pseudomyxoma Peritonei
Pseudomyxoma Peritonei
“scalloped appearance of the liver.”
Causes of Pseudomyxoma Peritonei
a. Ruptured mucocele (usually appendix)
b. Intraperitoneal spread of a mucinous neoplasm (Ovary, colon, appendix, pancreas)
It’s usually the appendix (least common is the pancreas).
dictates the location of implants
natural flow of ascites
why is the retrovesical space is the most common spot for peritoneal carcinomatosis?
it’s the most dependent part of the peritoneal cavity.
“posterior displacement of the bowel from the anterior abdominal wall.”
Omental Seeding/Caking
Omental Seeding/Caking
occurs 30-40 years after the initial asbestosis exposure.
Primary Peritoneal Mesothelioma
mesothehoma involving the pleura (and it does 75% of the time), but the other 25% of the time it involves the peritoneal surface.
Barium Peritonitis
The pathology is an attack of the peritoneal barium by the leukocytes which creates a monster inflammatory reaction (often with massive ascites and sometimes hypovolemia and resulting shock).
If barium ends up in the systemic circulation it kills via
Pulmonary embolism (50% of the time)
Risk is increased in patients with inflammatory bowel or diverticulitis (altered mucosa).
Mesenteric Lymphoma
is usually NHL
Mesenteric lymphoma
“Sandwich sign”
lobulated confluent soft tissue mass encasing the mesenteric vessels “sandwiching them.”
Mesenteric panniculitis
+ Retroperitoneal nodes = lymphoma
Misty mesentery
increased mesenteric fat density centered around the jejunal root, often with a few small nodes
6 month follow up
