Abdomen 2: Peritoneal Cavity

Front 1

Peritoneal Layers

Back 1

Peritoneal cavity is between parietal and visceral layers of the peritoneum. Visceral is directly on the gut tube.

The blood supply runs through both layers of peritoneum to reach the gut.

The mesentery lines the blood supply as it crosses the peritoneal cavity.

Front 2

Parietal/Visceral Peritoneum

Back 2

Parietal:
- supplied by blood vessels in abdominal wall
- Innervated by general sensory nerves (can feel pain)
- Drained by lymphatic vessels in abdominal wall

Visceral peritoneum:
- supplied by blood vessels of viscera
- innervated by visceral sensory fibers (not really painful)
- drained by lymphatic vessels from viscera

Front 3

Intraperitoneal organs

Back 3

Protrude completely into peritoneal sac. Almost completely invested by visceral peritoneum. May be mobilized.

Ex:
- stomach
- duodenum
- pancreas
- spleen
- jejunum
- ileum
- transverse colon
- sigmoid colon

Front 4

Retroperitoneal Organs

Back 4

Posterior to peritoneum

Ex:
- urinary structures (kidneys, suprarenal glands, ureter, bladder)
- circulatory structures (aorta, inferior vena cava)
- GI structures (esophagus, rectum, and parts of the duodenum, pancreas, ascending and descending colons)

Some intraperitoneal structures come in contact with body wall and become secondarily retroperitoneal.

Front 5

Process of becoming secondarily retroperitoneal

Back 5

1) Rotate intraperitoneal organ
2) Organ fuses with posterior body wall
3) Peritoneal layers fuse, organ is covered partially with parietal peritoneum, resulting in a secondarily retroperitoneal organ

Front 6

Peritonitis

Back 6

Inflammation of peritoneum. Results in ascites (excess fluid in peritoneal cavity). Can be caused by trauma or infection (like ruptured appendix).

Excess fluid can be drained by paracentesis.

Front 7

Greater Omentum

Back 7

Reflection of the peritoneum.

Suspended from the greater curvature of the stomach like an apron over the abdominal viscera.

Pathways for neurovascular structures.

Can wrap itself over inflamed structures and prevent peritonitis.

Front 8

Lesser Omentum

Back 8

Reflection of peritoneum.

A double layer of peritoneum from the lesser curvature of the stomach to the liver.

Provides pathways for neurovascular structures.

Composed of hepatogastric and hepatoduodenal ligaments.

Front 9

Omental foramen/omental bursa

Back 9

Boundaries of omental foramen:
- caudate lobe of liver
- first part of duodenum
- hepatoduodenal ligament
- inferior vena cava

Omental foramen: natural opening between lesser sac (omental bursa beneath lesser omentum) and greater sac (rest of peritoneal cavity).

Front 10

Omental Foramen problems

Back 10

Fluid can accumulate in the omental bursa (lesser sac) when the stomach or pancreas is injured.

In rare cases, intestine loop can herniate into lesser sac through the epiploic (omental) foramen.

If the cystic artery is severed during gall bladder removal, can plug hepatic artery with finger through omental foramen to stop bleeding.

Front 11

Portal triad

Back 11

Found within the hepatoduodenal ligament.

Contains:
- proper hepatic artery
- common bile duct
- portal vein

Front 12

Mesenteries

Back 12

Suspend organs from body wall, or connect organs to each other.

Double layer of peritoneum that reflects off body wall and enclose viscera.

Blood vessels travel between the two layers.

EX:
- mesentery of the small intestine
- transverse mesocolon
- sigmoid mesocolon
- mesoappendix

Front 13

Roots of the mesenteries

Back 13

Root of a mesentery is location on posterior body wall where peritoneum reflects to form double wall of the mesentery.

Basically the attachment on the body wall.

Front 14

Peritoneal Ligaments

Back 14

Double layer of peritoneum between organs are often called ligaments.

EX:
- gastrolienal
- lienorenal

They are subdivisions of the mesentery.

Front 15

Specific peritoneal ligaments

Back 15

Gastrolinal: extends from greater curvature of stomach to hilum of spleen. Contains short gastric and left gastroepiploic vessels.

Lienorenal ligament: extends from hilum of spleen to left kidney. Contains splenic vessels and tail of pancreas.

Falciform ligament: sickle shaped fold connecting liver to diaphragm and abdominal wall. Contains the ligamentum teres hepatis and paraumbilical vein.

Coronary ligament:
- composed of two triangular ligaments
- peritoneal reflection from liver onto diaphragm.
- encloses bare area of liver

Others include gastrophrenic, gastrocolic, phrenicocolic ligaments.

Front 16

Peritoneal Ligaments (embryological remnants)

Back 16

Ligamentum teres hepatis: lies in free margin of falciform ligament. Ascends from umbilicus to inferior liver. Formed after birth from remnants of left umbilical vein.

Ligamentum venosum: remnant of ductus venosus (which bypasses the liver since you don't need first pass as a fetus, your mom is already doing that).
Lies in fissure on inferior surface of liver.

Front 17

Vasculature of the gut

Back 17

Arteries of the gut run within the mesenteries to reach the organs.

Celiac trunk/axis supplies the foregut.

Superior mesenteric artery supplies the midgut.

Inferior mesenteric artery supplies the hindgut.

Front 18

Celiac trunk/axis (T12)

Back 18

Arises from aorta just below diaphragm.

Branches:
- common hepatic a. (proper hepatic, right gastric, gastroduodenal)
- splenic a.
- left gastric a.

Supplies foregut (stomach, liver, duodenum).

Front 19

Common hepatic artery

Back 19

Runs along upper border of pancreas.

Gives rise to:
- proper hepatic artery (travels in free edge of lesser omentum, divides into left and right hepatic arteries, with right giving rise to cystic artery)
- right gastric artery (runs along lesser curvature)
- Gastroduodenal artery (gives rise to right gastroepiploic artery and pancreaticoduodenal artery).

Front 20

Splenic artery

Back 20

Tortuous (winding) course, gives rise to short gastric arteries, and left gastroepiploic arteries

Front 21

Left gastric artery

Back 21

Smallest branch of celiac trunk.
Runs along lesser curvature.

Front 22

Celiac trunk and branches

Back 22

Learn using flash card!!!

Front 23

Superior Mesenteric Artery (L1)

Back 23

Arises from aorta behind neck of pancreas.

Branches:
- inferior pancreaticoduodenal artery
- middle colic
- ileocolic artery
- right colic artery
- jejunal and ileal branches

Supplies midgut and ascending colon.

Front 24

Inferior Mesenteric Artery

Back 24

Arises from aorta.

Branches:
- left colic
- sigmoid
- superior rectal

Supplies hindgut (transverse colon, descending colon, sigmoid colon and rectum(

Front 25

Summary vascular supply

Back 25

Celiac trunk/axis: foregut
Superior mesentery artery: midgut
Inferior mesentery artery: hindgut