Flashcards in Duodenum, Pancreas, Spleen Deck (47):
Where does the small intestine extend from and what are its parts? How does it change throughout?
From pyloric orifice of stomach to ileocecal valve. It is 6-7m long and divided into duodenum, jejunum and ileum
It becomes narrower throughout
What is the duodenum and its four parts? Which are peritoneal?
Shortest, widest, and most fixed part of small intestine.
1. Superior - initial part is peritoneal
4. Ascending - tail is peritoneal
Rest is retroperitoneal
What is the superior part of the duodenum and its two regions?
LV1 level - first part of duodenum, which connects the pyloric orifice to the descending duodenum. It is the most movable part, and is exposed to high acidity.
1. Proximal region - relatively mobile and acidic, attaches to hepatoduodenal ligaments and the greater omentum
2. Distal region - It surface is corrugated (ridged) has no mesentery and is immobile. It is retroperitoneal
What is the smooth part of the superior duodenum called? What clinical correlation can occur here and why?
Ampulla, duodenal cap, or bulb. It is the proximal superior duodenum.
Duodenal ulcers occur here as it receives acidic exudates from the stomach. May lead to peritonitis
What is related anteriorly, posteriorly, superiorly, and inferiorly to the superior duodenum?
Anterior: Quadrate lobe of liver = gall bladder
Posterior: Bile duct, portal vein, inferior vena cava, gasroduodenal artery
Superior: NECK of gall bladder
Inferior: NECK of pancreas
Where is the descending part of the duodenum?
Second part, it is retroperitoneal, and passes along right sides of LV1 to LV3. It passes to the right and parallel to the inferior vena cava during its descent.
What is the significance of the descending part of the duodenum?
The bile duct and main pancreatic duct enter the posteromedial wall, about 2/3 along its length. THey unit to form the hepatopancreatic ampulla, which opens on the major duodenal papilla
In some people, the bile and pancreatic ducts open separately into this area
What are the anterior, posterior, and medial relationships of the descending duodenum?
Anterior: Transverse colon + mesocolon, some coils of small intestine
Posterior: Hilus of right kidney, renal vesels, ureter, and right psoas major muscle
Medial: Head of pancreas, pancreatic + bile ducts
What is the horizontal part of the duodenum?
3rd part, runs right to left along LV3 retroperitoneally, passing anterior to IVC and abdominal aorta.
What are the anterior, posterior, and superior relationships of the horizontal part of the duodenum?
Anterior: Superior mesenteri artery + vein, coils of small intestine
Posterior: Right psoas major, IVC, aorta, right ureter
Superior: Head of pancreas, superior mesenteric vessels
What is the ascending part of the duodenum?
4th part, ascends left side of aorta at level of LV2. It bends anteriorly and joins the jejunum at the duodenojejunal flexure. The distal end is peritoneal and movable with the jejunum
What supports the duodenojejunal flexure?
Suspensory muscle / ligament of the duodenum, arising from right crus of diaphragm and attached to ascending duodenum
What are the anterior, posterior, and medial relationships to the ascending duodenum?
Anterior: Beginning of the root of the mesentery, coils of jejunum
Posterior: Left psoas major muscle, left margin of the aorta
Medial: Head of pancreas
Superior: Body of pancreas
What are the four recesses formed by the peritoneal folds at the duodenojejunal junction?
1. Superior duodenal
2. Inferior duodenal
3. Retroduodenal - (between the super and inferior duodenal recesses)
4. Paraduodenal - lateral side away from ascending duodenum, carries inferior mesentery vein in its fold
What is the primary blood supply to the duodenum?
1. Superior pancreaticoduodenal (PD) - branch of gastroduodenal supplying proximal half of duodenum
2. Inferior pancreaticoduodenal - branch of superior mesenteric supplying distal half of duodenum
Where do the superior and inferior PD arteries anastomose?
In the head of the pancreas to form an arterial arcade. Branches of these arteries supply the duodenum
Where might the superior part of the duodenum get blood?
Supraduodenal (from gastruoduodenal), right gastric, gastro-omental, or gastroduodenal arteries, since it is in close attachment to the stomach
What is the lymphatic and venous drainage of duodenum?
Veins follow arteries, and will drain into venous portal system by superior mesenteric
Lymph: PD nodes, pyloric nodes, superior mesenteric nodes all drain into CELIAC nodes
What is the innervation to the duodenum?
The vagus and sympathetic plexus on the PD arteries
Where does the pancreas lie and which parts are retroperitoneal?
Lies in transpyloric plane, across LV1 to LV3, divided into four parts: head, neck, body, and tail.
All retroperitoneal except for tip of tail
It is posterior to the stomach and omental bursa, and the transverse mesocolon is attach to its anterior margin
What is the head of the pancreas and what is its uncinate process?
Part located within curve of duodenum. Has a prolongation that is L-shaped and lies posterior to the superior mesenteric vessels.
What structures are posterior to the head of the pancreas?
Inferior vena cava, right renal vessels, bile duct
What is the neck of the pancreas and what forms behind it?
Part between head and body, it is grooved posterorly by the superior mesenteric vessels as it joins the splenic vein to form the portal vein
What covers the anterior surface of the pancreas?
Peritoneum, since it is retroperitoneal. Adjacent to this peritoneum is the pylorus of the stomach.
Where does the body of the pancreas lie? What two abdominal aorta branches does it lie between?
Across the aorta on LV1-LV3, retroperitoneally. It is posterior to the omental bursa, and the splenic artery runs superiorly.
Lies between celiac trunk and superior mesenteric
What is on the anterior surface of the body of the pancreas?
Peritoneum, bed of stomach where it provides attachment for transverse mesocolon
What organs are on the posterior surface of the body of the pancreas?
Left suprerenal gland and left kidney. Aorta and superior mesenteric artery are posterior
Where does the tail of the pancreas end?
Passes between two layers of splenorenal ligament, and usually contact the hilum of the spleen. Tip is peritoneal.
Where does the main duct of the pancreas run?
Posterior surface of the pancreas, from tail to head where it turns inferiorly and comes close to bile duct, forming hepatopancreatic ampulla
What are the three sphincters that regulate the flow of bile and pancreatic juices to duodenum?
1. Pancreatic duct sphincter (terminal part of main duct)
2. Choledochal sphincter (around bile duct)
3. Hepatopancreatic sphincter (around ampulla, gated by major duodenal apilla)
What is the accessory duct of the pancreas?
It drains part of the head of the pancreas and is variable. It usually joins the main duct, but may drain into the minor duodenal papilla in 9% of people
What is the arterial supply of the pancreas?
Splenic (mostly) and PD arteries. Remember superior and inferior (anterior / posterior) form an arcade in head of pancreas to supply the head and neck of pancreas.
Where is the primary venous drainage of the pancreas?
Into the splenic vein, though there is some portal and superior mesenteric contribution
What is the lymph drainage of the pancreas?
Mostly pancreaticosplenic nodes, or pylorid nodes. They all drain into celiac, hepatic, or superior mesenteric nodes
What is the innervation of the pancreas?
Vagus and splanchnic nerves. Splanchnic nerves carry visceral afferent for pain. SANS and PANS travel along arteries from celiac and superior mesenteric plexuses.
What is the spleen? Is it peritoneal?
Largest single mass of lymphoid tissue, located in LUQ. It is peritoneal
Where is the hilum of the spleen and what are its attachments? Where is it located?
Medial aspect of spleen, it is attached to the gastrosplenic and splenorenal ligaments. Branches of the splenic artery enter through here and branch, while splenic veins exit the hilum. It is intimately related to the tail of the pancreas
What are the two surfaces of the spleen and what do they contact?
Diaphragmatic - convex and smooth, contacting ribs 9-11, with a sharp superior border. THe posterior and inferior borders are rounded
Visceral - In contact anteriorly / medially to the posterolateral wall of the stomach, and posteriorly / medially to the superior lobe of the left kidney..
Thus, it has colic, gastric, and renal surfaces
What is the gastrosplenic ligament?
Ligament attaching spleen to greater curvature of the stomach
What is the splenorenal ligament?
Ligament attaching pole of left kidney to spleen, holds tail of pancreas and splenic vessels.
What arteries supply the spleen and what type of arteries are they?
5 or more branches of the splenic artery which enter the hilum from the splenorenal ligament.
They are called end arteries because they have no anastomoses and are the only blood supply to that portion of tissue.
What is the significance of no anastomoses between five terminal splenic arteries?
Obstruction of one of them could result in death of the splenic tissue of that area, since there is no other oxygen supply to that area.
What is the venous drainage of the spleen?
Via several tributaries emerging from hilum of spleen. Drains into splenic vein which runs posterior to the body and tail of the pancreas and is joined by the inferior mesenteric vein. This will continue to form the portal vein (with superior meseneteric)
What is the lymph drainage of the spleen?
Pancreaticosplenic lymph nodes, present on posterior surface of superior pancreas border
What are the nerves of the spleen?
Celiac plexus, they are largely VASOMOTOR
What is the most frequently ruptured abdominal organ?
Spleen. This leads to intraperitoneal hemorrhage and shock