Abdominal Viscera And Collateral Circulation Flashcards
What are the members of the marginal artery (of Drummond)
Proximal and distal branches of:
Superior mesenteric artery:
Ileocolic artery
Right Colic artery
Middle Colic artery
Inferior mesenteric artery:
Left colic artery
Sigmoid arteries
And then connected to the colon via vasa recta.
Describe the portal and caval venous drainage systems and the anastomoses
The inferior vena cava - drains the primary retroperitoneal organs
Portal vein - drains the secondary retroperitoneal organs and the peritoneal organs.
The portal vein:
The superior mesenteric vein goes directly into the portal vein. Then the superior rectal vein becomes the inferior mesenteric vein which drains into the splenic vein coming from the left to join the superior mesenteric and become the portal vein. The portal vein goes into the liver.
Three areas of anastomoses: rectal, umbilical, and esophageal.
Rectum and esophagus are the only organs where the large veins are in the lumen.
If there is portal hypertension and blood gets pushed in the valveless portal vein in the other direction…
Rectum: the superior rectal vein drains into the inferior and middle rectal veins (caval)- they’d dilate and express as hemorrhoid
Esophageal: the esophageal BRANCH vein joins the left gastric vein to enter the portal vein. However if pushed the other way it would enter the CAVAL esophageal vein and enter the larger and longitudinal AZYGOS vein into the caval vein. Swelling and then swallowing food can cause abrasion and vomit blood.
Umbilical: The paraumbilical veins drains into the epigastric veins which radiate into the subclavian and the common iliac veins. Swelling gives it the appearance of snakes so its called CAPUT MEDUSSAE (a visible symptom)
Describe the three kinds of treatments around portal hypertension
- Splenorenal shunt - connects the splenic vein (portal) and the renal vein (caval) giving it a passage way to avoid the liver
- Portacaval shunt - directly connects the inferior vena cava and the portal vein so portal vein also directly empties.
- Most popular: Transjugular Intrahepatic Portasytemic Shunt (TIPS)
Use a catheter and enter the right jugular, go through the right atrium, through the inferior vena cava, reach the hepatic vein of the liver and connect the portal vein and the hepatic vein (Caval) wtf this sounds harder…
Describe the abdominal circulation of the foregut
Foregut: Aorta > Celiac trunk (short) 1. Left gastric artery - runs directly along the lesser curvature 2. Splenic artery 3. Common hepatic artery
Left gastric artery: gives off a branch of the esophageal artery before it reaches the stomach.
Splenic artery - branches inferiorly to go along the greater curvature and is known as the left gastro-omental artery
- branches superiorly to supply the fundus of the stomach known as Short Gastric Arteries
- it ends supplying the spleen
Common hepatic artery:
Superiorly branches into proper hepatic artery which supplies the liver>branches OFF the right gastric artery > branches INTO right and left hepatic artery
Right hepatic artery>cystic artery
Inferiorly the Gastroduodenal artery branches off the common hepatic artery > branches OFF left as the right gastro-omental artery > continues into the Superior Pancreatico-duodenal Artery
What is the arterial supply of the midgut and hindgut?
The superior mesenteric artery >branches OFF the inferior pancreaticoduodenal artery > branches OFF the middle colic (transverse colon) >
To the right:
Right Colic Artery (ascending colon) > then branches OFF the Ileocolic artery
> branches OFF the appendicular artery
The inferior and superior pancreatico-duodenal artery anastomose in the HEAD OF THE PANCREAS, so the superior mesentary can take over supplying the foregut.
To the left: Jujunal arteries (small arches, long vasa recta) Ileal arteries (long arches, short vasa recta) Along the transverse mesocolon
Cut the mesocolon to see the inferior mesenteric arteries:
Left colic artery - descending colon
Sigmoid artery - sigmoid colon
Superior rectal artery - continuation of the inferior mesenteric artery
Describe the respiratory diaphragm
There are three openings
A caval hiatus - which is just tendenous and so won’t contract and squeeze the vena cava
An esophageal hiatus - which does have muscle and it serves a function
Aortic hiatus - opening for the aorta and the aorta passes behind the diaphragm so when it contracts, it won’t squeeze the aorta.
Describe the esophagogastric junction and its potential abnormalities
The esophagus and the stomach is separated at the Z line - a region where the esophageal and gastric mucosa meet.
This is normally closed due to the right crura on either side of the esophagus hiatus.
Only when swallowing, it allows food to enter the stomach, then closes so the acid doesn’t touch the walls of the esophagus.
The Z line is held in place by the phrenoesophageal ligaments
2 conditions.
1. Sliding type: the abdominal esophagus, cardia and parts of fundus slide up the esophagus hiatus and so the sphincter doesn’t work and you get REGURGITATION.
- Paraesophageal type: you have the cardia in the normal position but part of the fundus is in the thorax. NO REGURGITATION
Describe the abdominal cavity subdivisions.
Where is surgical entry into the lesser sac (aka omental bursa)?
The gastrocolic ligament (attaching the stomach to the transverse colon) is very long and fuses to form the greater omentum.
There is a dorsal mesentary connecting the transverse colon to the peritoneum of the aorta. THis is the transverse mesocolon.
Superior to that is the lesser sac.
The gastrocolic ligament distinguishes the supracolic compartment, basically anterior to it and along the anterior abdominal wall.
The whole compartment below the transverse mesocolon is the infracolic compartment.
Surgical entry would be through the greater omentum right below the stomach (aka gastrocolic ligament)
What is lymphatic drainage in the abdomen?
Drainage is first to the preaortic and paraaortic lymph nodes > cysterna chylae (inferior continuation of the thoracic duct) > and then into IVC.
What is the land mark for the end of the foregut?
For the duodenum, what is its origins?
Where the common bile duct enters the second part of the duodenum.
Proximal first part is peritoneal
Distal first, and then 2nd, 3rd, 4th are retroperitoneal.
Describe the blood supply to the pancreas
*splenic vein is posterior to the pancreas.
Head and neck——————————-
Superior pancreaticoduodenal arteries (anterior and posterior) a branch off of and the continuation of the gastroduodenal artery.
Inferior pancreaticoduodenal artery comes off of the superior mesenteric artery which is running behind the neck of the pancreas. Is the earliest branch of the SMA and also has anterior and posterior.
The splenic artery runs along the superior border of the pancreas (the tail of the pancreas contacts the spleen so it makes sense)
Describe the whipple procedure.
THere is a tumor in the head of the pancreas.
You separate and remove the head of the pancreas, duodenum, right gastroomental artery, superior and inferior pancreaticodudonal arteries, gastroduodenal artery
Then combine this way.
Neck of pancreas to the jejunum. (so bile can still enter)
Stomach to the jejunum.
Common hepatic duct to the jejunum connecting liver to the jejunum.
What is the hepatocystic triangle of Calot?
It is an upside down triangle formed by the bifurcation of the cystic duct and the common hepatic duct.
In the area is the cystic artery coming off of the right hepatic artery which is a division of the proper hepatic artery.
What is the arrangment of the kidneys?
What is the arrangment of vasculature at the hilium?
Ureteric bud derived- Renal pyramids (thousands of collecting tubules) > renal papilla > minor calyces > major calyces > renal pelvix.
Metanephric blastema derived:
Renal columns, renal medulla, renal cortex (filtration portion)
The renal vein and renal artery and renal pelvis enter the hilium.
Renal vein is the most anterior.
Renal artery is a little superior
Rectal pelvis opening into the ureter is the most posterior.
What are the three arterial anastomoses in this block?
- Celiac trunk > pacreaticoduodenal arcades (superior;anterior,posterior, inferior) > superior mesenteric artery
- Superior mesenteric artery > marginal artery of Drummond> inferior mesenteric artery
- Inferior mesenteric artery > superior rectal artery —-middle rectal and inferior rectal (branches of internal pudendal artery) > internal iliac artery.
