Using the Sectra table, you will identify structures of the abdomen. Bolded terms are in the objectives for this lab.
The Abdominal Region II
“The abdomen is the portion of the trunk between the thorax and the pelvis. Superiorly, the abdominal cavity is physically divided from the thoracic cavity by the diaphragm. Inferiorly, the abdominal cavity is continuous with the pelvic cavity, and thus, this region is commonly referred to as the abdominopelvic cavity. The abdominal organs (viscera) are not bilaterally symmetrical. Therefore, it is worth noting that use of the words “right” and “left” in names and instructions refers to the right and left sides of the cadaver in the anatomical position.” – Grant’s Dissector 16th ed.
You will not be able to highlight the features of many viscera on the model. Use the MPR images to relate diagrams and cadaveric pictures to these features. As you identify and dissect neurovascular structures, you should review their pathways.
If you are having trouble highlighting narrow structures (arteries, veins, nerves), you can search for them by selecting the Anatomy tab, typing the name of the structure in the search box, and selecting the sun icon next to the listed structure. You can dissect these structures by selecting the eye icon.
As you highlight a structure, note that the structure will also be highlighted in the multiplanar reconstructed (MPR), or cross-sectional images in the leftmost pane. All structures should be identified on the MPR images. Using three fingers, scroll through the MPR images to understand the three-dimensional relationships between different structures as you work though the lab. Structures that are difficult to identify in the MPR images will have additional links to assist you.
Liver and portal system
Begin your dissection (select this button at any time to start over):
- Identify the left lobe and right lobe of the liver. The caudate lobe and quadrate lobe are grouped with the right lobe, identify them on the the diagrams below
- Use the diagrams below to identify other features of the liver: diaphragmatic surface, bare area, inferior border, visceral surface, porta hepatis, coronary ligaments, and ligamentum venosum
- Identify the falciform ligament and the round ligament of the liver (ligamentum teres hepatis) (MPR)
- Identify the gallbladder on the inferior surface of the liver
- Dissect the left and right lobes of the liver, as well as the falciform ligament and observe the veins within the liver. Identify the hepatic portal veins running into the liver, and the hepatic veins that run from the liver to the inferior vena cava (MPR)
- Identify the veins that drain into the portal vein: superior mesenteric vein and splenic vein
- Identify the inferior mesenteric vein, which drains into the splenic vein (MPR)
- Identify the cystic duct connecting to the gallbladder (MPR)
- Identify the ducts leading from the cystic duct to the liver: common hepatic duct, left hepatic duct, right hepatic duct
- Identify the common bile duct leading from the cystic duct to the duodenum
- Identify the arteries leading to the liver: common hepatic artery, hepatic artery proper, and left and right hepatic arteries (these don’t connect properly to the hepatic artery proper on the model. Use the diagrams below to understand their arrangement) (MPR)
- Identify the cystic artery leading from the right hepatic artery to the gallbladder
Q1: What structures are part of the portal triad? (answer)
Branches of the celiac trunk
Use the following view to view the arteries arising from the celiac trunk and associated viscera:
- Identify the stomach and it’s features: body, greater curvature, lesser curvature, cardia, fundus, pylorus, gastric folds (gastric rugae), and pyloric sphincter (only the pylorus is selectable on the model, use the diagrams below to study the parts of the stomach)
- Identify the arteries along the lesser curvature of the stomach: the left gastric artery and right gastric artery
- Identify the arteries along the greater curvature of the stomach: the left gastro-omental (gastroepiploic) artery and right gastro-omental (gastroepiploic) artery. The left gastro-omental artery is only partially visible on the model.
- Dissect the stomach (and “pyloric part”)
- Identify and dissect the pancreas. The parts of the pancreas (head, unicate process, neck, body, tail) are not visible on the model, identify them on the diagrams below (MPR)
- Identify the pancreatic duct. It divides close to the duodenum: the inferior branch is the main pancreatic duct and the superior branch is the accessory pancreatic duct (MPR)
- The main pancreatic duct joins the common bile duct at the hepatopancreatic ampulla (Ampulla of Vater) just before they empty into the duodenum. This is not selectable on the model, use the diagrams below to study the relationship of these structures
- Identify the parts of the duodenum: ampulla of the duodenum (duodenal cap), superior (first) part, descending (second) part, horizontal (third) part, and ascending (fourth) part. These will not be selectable on the model, use the diagrams below to understand the 4 regions of the duodenum
- The internal features of the duodenum are not selectable on the model: use the diagrams to identify the plicae circularis (circular folds), major duodenal papilla, and minor duodenal papilla
- Identify the arteries branching from the common hepatic artery that go to the duodenum and pancreas: the gastroduodenal artery and superior pancreaticodudenal artery (MPR)
Q2: What travels through the pancreatic ducts? What else is produced by the pancreas? (answer)
- Identify the celiac trunk and it’s three branches: the common hepatic artery, the splenic artery, and the left gastric artery (MPR)
- Identify the spleen
The mesenteric arteries
Use the following view to examine the arteries arising from the superior mesenteric artery, inferior mesenteric artery, and associated viscera:
- Identify and dissect the parts of the small intestine: duodenum, jejunum, ileum
- Identify the superior mesenteric artery and its branches: inferior pancreaticoduodenal artery, jejunal arteries, ileal arteries, ileocolic artery, right colic artery, and middle colic artery (MPR)
Q3: What structure does each of the branches of the superior mesenteric artery supply? (answer)
- Identify the inferior mesenteric artery and its branches: left colic artery, sigmoid arteries, and superior rectal artery (MPR)
- The marginal artery of Drummond is not visible on the model. Identify it on the diagram below
- Identify the parts of the large intestine: cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum
- The appendix and appendicular artery are not present. Identify them on the diagrams below
- Using the diagrams below, identify features of the large intestine: haustra, teniae coli, omental appendices (epiploic appendages), and semilunar folds (plicae semilunaris)
Q4: Where are the right and left colic flexures? What structure does each branch of the inferior mesenteric artery supply? (answer)
Q5: Where are anastomoses between the superior mesenteric artery and inferior mesenteric artery? (answer)
Posterior abdominal wall
Use the following view to examine structures of the posterior abdominal wall and paired arteries of the abdominal aorta:
- Dissect the retroperitoneal fat and perirenal fat to expose the posterior wall of the abdominal cavity on the left and right sides
- Identify the paired arteries coming off the abdominal aorta: left and right renal arteries, gonadal (testicular/ovarian) arteries, and common iliac arteries. The testicular arteries are not complete on the model. (MPR)
- Identify the paired veins of the posterior abdominal wall: left and right renal veins, gonadal (testicular/ovarian) veins, and common iliac veins
- While not selectable, observe the aperatures of the diaphragm by noting what structures pass through them: the inferior vena cava passes through the caval opening, the abdominal aorta passes through the aortic hiatus, and the esophagus (absent) passes through the esophageal hiatus (MPR)
Q6: Observe the relationship between the superior mesenteric artery and the left renal vein. How does this relationship contribute to “nutcracker syndrome”? (hint) (answer)
- Identify the left and right kidney and suprarenal gland
- Identify the left and right ureter and renal pelvis (MPR)
- Dissect the left kidney to observe the fat occupying the renal sinus. Use the diagrams to understand the structures of the kidney: renal (fibrous) capsule, renal cortex, renal columns, renal medulla, renal pyramids, renal papilla, minor calyx, and major calyx
Q7: Where are common constriction sites of the ureter? (answer)
- Identify the muscles of the posterior abdominal wall: psoas major, quadratus lumborum, and iliacus (MPR)
- The psoas minor is not present on the model. Use the diagrams below to identify it
- Dissect the pararenal fat and identify the subcostal nerve (T12) on the left and right sides
- Identify the spinal nerves on the posterior abdominal wall on the left and right sides: iliohypogastric nerve (L1), ilioinguinal nerve (L1), genitofemoral nerve (L1/L2), lateral femoral cutaneous nerve (lateral cutaneous nerve of the thigh L2/L3), femoral nerve (L2-L4), obturator nerve (L2-L4), and lumbosacral trunk (L4/L5)
- Dissect the psoas major to observe these nerves as they exit the spinal column (MPR)
- The sympathetic trunks are not visible on the model. Observe them in the diagram below
End of Sectra activity
Answers to activity questions
Below are answers to questions asked during the activity. Clicking the ‘back to lab’ link below each answer will take you back to the question (you may need to scroll up a little to view the question again).
Q1: What structures are part of the portal triad?
- the proper hepatic artery, the portal vein, and the common bile duct
Q2: What travels through the pancreatic ducts? What else is produced by the pancreas?
- bicarbonate and digestive enzymes travel through the pancreatic duct to the duodenum. The pancreas also produces insulin and glucagon (hormones).
Q3: What structure does each of the branches of the superior mesenteric artery supply?
- Inferior pancreaticoduodenal artery: distal duodenum & head of pancreas
- Small Intestinal (jejunal and ileal) arteries: jejunum & ileum
- Ileocolic artery: terminal ileum, cecum
- Appendicular artery: appendix
- Right colic artery: ascending colon
- Middle colic artery: transverse colon
Q4: Where are the right and left colic flexures? What structure does each branch of the inferior mesenteric artery supply?
- The right colic flexure (hepatic flexture) is where the ascending colon transitions to the transverse colon, deep to the 9th and 10th ribs and overlapped by the inferior part of the liver. The left colic flexure (splenic flexure) is where the transverse colon transitions to the descending colon, anterior to the inferior part of the left kidney
- Left colic artery: descending colong
- Sigmoid arteries: sigmoid colon
- Superior rectal artery: proximal part of the rectum
Q5: Where are anastomoses between the superior mesenteric artery and inferior mesenteric artery?
- The superior mesenteric artery and inferior mesenteric artery anastomose along the marginal artery (of Drummond)
Q6: Observe the relationship between the superior mesenteric artery and the left renal vein. How does this relationship contribute to “nutcracker syndrome”?
- The left renal vein can become compressed between the superior mesenteric artery and the abdominal aorta, causing renal vein hypertension
Q7: Where are common constriction sites of the ureter?
- The junction of the renal pelvis and the ureter (the pelvi-ureteric junction), where the ureter crosses over the bifurcation of the common iliac artery, and where the ureter enters the bladder wall (the vesicoureteric junction) are the 3 most common sites of constriction of the ureter