Flashcards in Abdomen III Deck (40):
At what level does the SMA appear?
What is the direction of the branches of the SMA?
SMA branches enter the mesentery and move to the right toward the right iliac fossa (colic side) EXCEPT the jejunal and ileal branches to the left small intestine.
The SMV is located ___________ to the SMA.
What are the branches of the SMA and the organs they supply?
Inferior pancreaticoduodenal: ½ duodenum & pancreas
Middle colic: right 2/3 of Transverse colon
Right colic: ascending colon
Ileocolic: cecum + appendix artery
Jejunal and ileal branches
What are the branches of the ileocolic artery?
Anterior cecal artery
Posterior cecal artery
At what level does the IMA appear?
What is the direction of the branches of the IMA?
The IMA runs downwards behind the 3rd part of the duodenum toward the Left iliac fossa. All three branches are to the Left.
How does the IMA end?
The IMA ends by crossing the left common iliac artery and becoming the superior rectal artery
What is the marginal artery of drummond?
The marginal artery of Drummond is an arterial arcade along the colon that interconnects the right, middle and left colic arteries.
What are the branches of the IMA and the organs they supply?
Left colic - left 1/3 of transverse colon and upper end of descending colon
Sigmoid arteries - lower end of descending colon and sigmoid colon.
Superior rectal - sigmoid colon and rectum (direct continuation of IMA)
Name the arterial anastamoses of the GI tract.
Pancreatic duodenal arteries anastamose (from SMA and Celiac Trunk)
Marginal Artery of Drummond
Anastomoses within the celiac trunk
True or False: The entire small intestine is retroperitoneal. Explain.
FALSE. The 1st part of the duodenum is intraperitoneal. The 2nd, 3rd, 4th parts of the duodenum, and the jejunum and ileum are retroperitoneal.
What artery supplies the jejunum and ileum?
Ileac and jejunal branches of the SMA.
Describe vascularity of the jejunum versus the ileum.
Describe the vasa recta of the jejunum versus the ileum.
Describe the arterial arcades of the jejunum versus the ileum.
Jejunum: few large loops
Ileum: many short loops
Describe the mesentery fat and walls of the jejunum versus the ileum.
Jejunum: less fat; thicker wall
Ileum: more fat; thinner wall
Where does the jejunum and ileum begin and end.
The jejunum begins at the duodenojejunal flexure and the ileum ends at the ileocecal junction/valve.
What is the blood supply of the large intestine?
The SMA (middle colic, right colic, ileocolic) and IMS (all 3 branches)
Describe the 3 unique features of the large intestine.
1. Appendices epiploicae (Omental appendices) - small pouches filled with fat that look like the appendix
2. Taenia Coli - longitudinal band muscle that causes formation of Haustra
3. Sacculations (Haustra) - rows of pouches.
True or False: The entire large intestine is retroperitoneal. Explain.
FALSE. Only the ascending and descending colon and rectum are retroperitoneal. The mesoappendix, transverse mesocolon, and sigmoid mesocolon are intraperitoneal.
What are the most common regions of the appendix?
1st most common: retrocecal
2nd most common: pelvic
What is the landmark of the appendix for surgery?
The 3 taeniae coli meet at the base of the appendix which is a useful landmark in surgery.
What is McBurney’s Point?
McBurney’s Point is the point of maximum tenderness in acute appendicitis.
How do you find McBurney’s Point?
McBurney's point is at the center of a fake line connecting the Right anterior superior iliac spine to the umbilicus.
To what dermatome is referred pain from acute appendicitis?
What are the 2 differential diagnoses for acute appendicitis?
Ectopic pregnancy (if missed period)
What is Meckel's diverticulitis?
An intestinal duct that should be obliterated after birth becomes inflamed.
What features differentiate Meckel's diverticulitis from acute appendicitis?
Syndrome of 2's
2 feet from IC valve
2 inches long
2% of population
2% are symptomatic
2 types of ectopic tissue (gastric and pancreatic)
2 years of age at clinical presentation,
2 X more common in boys
Which veins form the portal vein?
The splenic (with received IMV) and the superior mesenteric veins form the portal vein.
What is the function of the portal vein at the liver?
The portal vein branches right and left at the porta hepatis of the liver to supply it with 75% of its blood and 50% of the required oxygen.
What is the order of vessels in the porta hepatis?
The portal vein is the most posterior structure arranged in VAD (portal Vein, hepatic Artery, hepatic Duct) from posterior to anterior
Which of the following is NOT a real vein?
Superior mesenteric vein (SMV)
Right & Left gastric veins
The Celiac Vein and Gastroduodenal Vein do NOT exist.
What is Portosystemic anastomosis?
Anastomosis of veins between with the systemic caval system (IVC+ Azygos) and the portal (liver) system.
What are the 3 most important Portosystemic anastomoses?
Left gastric vein and the esophageal vein
Superior rectal vein and the middle and inferior rectal veins
Paraumbilical veins and the superficial epigastric veins
What are the results of liver cirrhosis?
Portal hypertension that leads to:
Esophageal varices -Hematemesis (vomiting blood)
Rectal varices (Hemorrhoids) - bleeding per rectum
Caput medusae - varicose veins radiating from the umbilicus (Medusa’s head)
What is the action of sympathetic innervation in the GI tract?
Inhibits peristalsis and activates sphincters.
What is the action of parasympathetic innervation in the GI tract?
Activates peristalsis and inhibits sphincters.
Describe parasympathetic innervation of the foregut, midgut, and hindgut.
Foregut & midgut - Vagus nerves
Hindgut - Pelvic splanchnic nerves (S2, 3, 4)
All these fibers are preganglionic and will relay in the terminal ganglia of their organs.