Prelab Images - Duodenum, Pancreas, Liver, & Gallbladder

Prelab should consist of reading the lab manual and dissector answers and viewing the dissection video. To begin your study, you may find it useful to look over the Netter's or LWW Atlas images listed below.

Step 1. Expose the duodenum and pancreas and define their parts. (Play movie)

The learning module reviews the development of the duodenum and pancreas. Plates N273, N274, N298 or TG5-26, N310 or TG5-18, and N329 or TG5-26 all show the pancreas and duodenum in relation to retroperitoneal structures. Plate N272 or TG5-18 shows the attachment of the gastrocolic ligament to the transverse colon cut and the stomach turned up to expose the posterior body wall peritoneum and the pancreas. Plate N272 or TG5-18 also shows the tail of the pancreas and the splenic artery in the splenorenal ligament. Plate N279 or TG5-26 shows the mesentery attaching to the fourth part of the duodenum and the superior mesenteric artery crossing the third part of the duodenum. Next, remove as much of the mesentery as you can to reveal the pancreas and duodenum. Plate N279 or TG5-26 labels the four parts of the duodenum and plate N268 or TG5-26 shows the vertebral level of the duodenum. Plate N270 (bottom) or TG5-26 labels the suspensory muscle of the duodenum (ligament of Treitz). Plate N270 (top) or TG5-14 shows the retroduodenal fossa (superior and inferior parts) and the paraduodenal fold (with embedded inferior mesenteric vein). Plate N279 or TG5-26 shows the relation of the third part of the duodenum to the superior and inferior mesenteric arteries. Plate N298 or TG5-26 labels the uncinate process, head, neck, body, and tail of the pancreas. Plate N301 or TG5-27 shows the relation of the pancreas to the celiac trunk, superior mesenteric artery, splenic artery and vein, and the bile duct. The vessels to the pancreas and duodenum are small and difficult to find. Begin by finding the gastroduodenal artery (N310 or TG5-19, N and N301 or TG5-27) and trace it as it gives off the posterior superior pancreaticoduodenal artery and then branches into the right gastro-omental and the anterior superior pancreaticoduodenal artery. The anterior superior pancreaticoduodenal artery will go deep to the duodenum, but superficial to the pancreas (pass between the two, plate N301 or TG5-27). The posterior superior pancreaticoduodenal artery will pass deep to both the pancreas and the duodenum. Plate N306 or TG5-27 shows the common stem of the inferior pancreaticoduodenal artery branching off the superior mesenteric artery. The common stem then branches into anterior (will anastomose with the anterior superior pancreaticoduodenal artery to form the anterior arcade superfical to the pancreas) and posterior branches (will anastomose with the posterior superior pancreaticoduodenal artery to form the posterior arcade on the posterior surface of the pancreas). Plate N304 or TG5-27 shows the blood supply to the pancreas and duodenum from a different view. The arteriae rectae are not labeled in plate N304 or TG5-27, but they are the tiny branches coming off the anterior and posterior arcades.

Step 2. Incise the peritoneum at the right border of the duodenum and reflect it medially. Identify the arterial supply to the pancreas and duodenum. (Play movie)

Looking at plate N301 or TG5-26, incise the peritoneum along the right side of the second part of the duodenum and reflect the duodenum and pancreas medially (like in plate N304 or TG5-27). Plate N294 or TG5-24 traces the bile duct from the liver through the pancreas and to the second part of the duodenum. Plate N304 or TG5-27 shows the posterior superior pancreaticoduodenal artery crossing the bile duct. Plate N306 or TG5-27 shows the origin of the posterior inferior pancreaticoduodenal artery from the inferior pancreaticoduodenal artery (branch off the superior mesenteric artery). Plates N301 or TG5-27 and N304 or TG5-27 show the posterior arcade being formed by the posterior superior and posterior inferior pancreaticoduodenal arteries. Plate N301 and N301 or TG5-27 shows the splenic artery, which gives off small pancreatic branches and small branches to the tail of the pancreas. Plates N N301 or TG5-27, and N304 or TG5-27 show the dorsal pancreatic artery dividing into the inferior pancreatic artery (left branch) and a right branch arcade. The right branch (labeled anastomotic branch in N301 or TG5-27 and N304 or TG5-27) will anastomose with the anterior superior pancreaticoduodenal artery to form the prepancreatic arcade (N not labeled). Plates N309, N311, and N312 or TG5-28 show the veins of the duodenum and pancreas that roughly travel with the arteries of the same name.

Step 3. Trace the splenic vein to its junction with the superior mesenteric vein and the formation of the portal vein. (Play movie)

Plates N311 or TG5-27 and N312 or TG5-28 show the splenic vein, inferior mesenteric vein, and the portal vein. Variations of the portal system are seen in plate N313. Plates N314 or TG5-35A and N315 or TG5-35B feature the lymph drainage. These lymph nodes will eventually drain into the cisterna chyli in plate N266 or TG5-37.

Step 4. Incise the duodenum and examine its interior including the papillae and folds. (Play movie)

Plate N279 or TG5-26 shows the duodenum opened up and identifies the circular folds, greater (major) duodenal papilla of Vater, and the lesser duodenal papilla. The pyloric sphincter is labeled pylorus in plate N276 or TG5-19 and is also shown (not labeled) in plate N279 or TG5-26. Plate N304 or TG5-27 shows the bile duct entering the pancreas. Trace it through the pancreatic tissue to the duodenum (see plate N279 or TG5-26). Plate N294 or TG5-24 shows the bile duct and the pancreatic duct uniting at the hepatopancreatic ampulla (of Vater). Plate N295 shows variations of the union of the bile and pancreatic ducts at the hepatopancreatic ampulla. Plate N288 or TG5-24 shows the hepatic artery, portal vein, and bile duct within the hepatoduodenal ligament. Plate N315 or TG5-35 shows the hepatic lymph nodes and plates N319, N320, and N322 show the hepatic plexus of nerves along the structures of the hepatoduodenal ligament. Plates N310 or TG5-19, N273, and N331 or TG5-42 should give you an idea of the inferior vena cava location in relation to the hepatoduodenal ligament.

Step 5. Expose pancreatic ducts on the posterior aspect of the pancreas. (Play movie)

Plates N279 or TG5-26, N294 or TG5-24, and N298 or TG5-27 show the pancreatic duct traced out. Plate N279 or TG5-26 shows an accessory pancreatic duct emptying into the minor duodenal papilla. Plates N N301 or TG5-27, and N304 or TG5-27 show the great pancreatic artery branching off the splenic artery. After tracing this artery you will have dissected the entire blood supply to the pancreas and duodenum (N N301 or TG5-27, and N304 or TG5-27).

Step 6. Examine the liver, gallbladder and biliary system, defining their peritoneal relations and parts. (Play movie)

The learning module and animations from previous labs review the development of the ventral mesogastrium. The falciform, coronary, left triangular, and right triangular ligaments are labeled in plate N287 or TG5-21. Plates N286 or TG5-21, N348, and N331 or TG5-42 show the surface projection of the liver and the location of the liver in the abdominal cavity. The gallbladder (fundus portion) can be seen peeking out from behind the liver in plate N287 or TG5-21. Plate N294 or TG5-24 labels the fundus, body, and neck of the gallbladder. Plate N286 or TG5-24 shows the gallbladder's relation to the duodenum and the transverse colon. Remove the remaining parts of the hepatoduodenal ligament (N288 or TG5-24) to give you a view like plate N310 or TG5-19. Trace the bile duct (N310 or TG5-19) to the porta hepatis (N287 or TG5-21). Plate N294 or TG5-24 identifies the cystic duct, common hepatic, and left and right hepatic ducts (N294 shows variations of the cystic and hepatic ducts). Plate N310 or TG5-19 and N301 or TG5-27 shows the proper hepatic artery, right and left hepatic arteries, and the cystic artery. Plate N306 or TG2-25 shows the many variations in the blood supply to the liver and gallbladder (aberrant hepatic arteries). Plates N312 or TG5-28 and N313 identify the small cystic veins going from the gallbladder into the liver. Remove the peritoneum from the gall bladder so you can move it away from the liver to better see the structures at the bottom edge of the liver (N310 or TG5-19). Cut through the falciform and coronary ligaments (N287 or TG5-21) at the top edge of the liver. Next, cut the inferior vena cava above the liver as close to the diaphragm as possible (N shows the inferior vena cava going through the diaphragm). Now you can reflect the liver downward to identify the diaphragmatic surface, the visceral surface and the bare area (N287 or TG5-21). Plate N289 or TG5-23 identifies the anatomical and functional lobes of the liver. Plate N275 or TG5-18 shows the lesser omentum attaching to the liver (it is continuous with the coronary and falciform ligaments in plate N287 or TG5-21). Plate N312 or TG5-28 traces the portal system and identifies right and left branches of the portal vein. Plate N287 or TG5-21 (top) shows the round ligament of the liver (ligamentum teres hepatis or the obliterated umbilical vein) running from the umbilicus to the liver. Plate N287 or TG5-21 shows the ligamentum venosum continuous with the round ligament and continuous superiorly with a hepatic vein that will drain into the inferior vena cava. Plate N229 shows the fetal circulation. Blood flows from umbilical vein (future round ligament) and is shunted past the liver by the ductus venosus (future ligamentum venosum) to the heart. Plate N265 or TG5-34 shows three hepatic veins that go from the liver to the inferior vena cava. Plate N315 or TG5-35 shows the lymphatic drainage of the liver and the hepatic lymph nodes. Plate N312 or TG5-28 shows the portal system and the four major portacaval anastomoses. Plates N238 (esophageal), 399 (superior rectal), and N256 or TG5-02 (paraumbilical) and TG5-28 will give you a better view of three of the portacaval anastomoses. Plate N289 or TG5-23 reviews the anatomical and function segmentation of the liver. Plates N288 or TG5-24, N291, and N292 show the blood flow and bile flow within the liver. These plates may help you to understand some concepts of the liver.

 

 

Updated: 11January 2012