2.) Relieve the diaphragm from any attachments to the ribs and/or costal cartilage. This can be completed by placing your hand between the ribs and/or costal cartilage and diaphragm, and bluntly separating the muscle. If further dissection is necessary, take care to maintain the diaphragm.

3.) Following the midaxillary lines (in-line with previous dissections), cut ribs 7-10, and remove the anterior portions of these ribs completely.

Photo 2. Procedural: removing anterolateral portions of ribs 7-10

Photo 3. Ventral cavity

Locate the stomach and liver, and explore portions of the greater and lesser omenta

Find these structures:

• Stomach

• Liver

• Greater omentum

• Lesser omentum

  • Hepatoduodenal ligament

4.) Locate the stomach and liver.

Note: The stomach is typically located in the left upper quadrant, whereas the liver spans both of the upper quadrants. The stomach often appears deflated in donors, and may be similar in caliber to the large intestine.

Photo 4. Stomach and liver, in situ

5.) Identify the remnants of the greater omentum and lesser omentum. Many features were located in previous labs.  Find the hepatoduodenal ligament, which is a component of the lesser omentum.

Note: The lesser omentum is composed of the continuous hepatoduodenal and hepatogastric ligaments.

Note: The hepatoduodenal ligament is located between the liver and the duodenum. The portal triad (bile duct, hepatic artery proper, and portal vein) is conducted through this ligament.

Photo 5. Greater and lesser omenta

Photo 6: Hepatoduodenal ligament

Identify the abdominal part of the esophagus, the parts of the stomach, and the spleen

Find these structures:

• Esophagus

  • Abdominal part

• Stomach

  • Gastric folds (rugae)

  • Greater curvature

  • Lesser curvature

  • Pyloric sphincter

6.) Identify the abdominal part of the esophagus.

Note: The esophageal mucosa transitions into gastric mucosa around T11. This is referred to as the esophagogastric junction.

Photo 7: Esophagus and stomach

7.) Identify the curvatures of the external stomach.

Note: The stomach has two distinct curvatures. The lesser curvature is superior, concave, and shorter. The greater curvature is inferior, convex, and longer.

Photo 8: Lesser and greater curvatures

8.) Pull the distal stomach anteriorly, and separate this structure from any deep structures. Using scissors, incise the GIT at the pyloric sphincter.

Photo 9: Pyloric sphincter

9.) On a plastinated specimen, locate the gastric folds (rugae). You may also incise the anterior wall of the stomach to see the gastric folds on your donor.

Note: Gastric folds are most obvious around the greater curvature and the pyloric part.

Photo 10: Gastric folds (rugae)

Identify the parts of the liver and gallbladder

Find these structures:

• Liver

  • Diaphragmatic surface

    • Fissure for the ligamentum venosum

    • Ligamentum venosum

  • Visceral surface

    • Porta hepatis

    • Fissure for round ligament of liver

    • Round ligament of liver

  • Gallbladder

10.) Locate the liver and gallbladder.

Note: There are two prominent anatomical lobes of the liver: a larger right lobe and smaller left lobe. To see the two accessory lobes (quadrate and caudate), an inferior view (visceral surface) is necessary. The quadrate lobe is more anteriorly positioned and next to the gallbladder and round ligament of the liver. The caudate lobe is more posteriorly positioned, comma-shaped, and lies between the inferior vena cava and ligamentum venosum.

Photo 11: Anterior view of liver

Photo 12: Visceral (inferior) surface of the liver

Photo 13: Visceral (inferior) surface of the liver

Photo 14: Visceral (inferior) surface of the liver

11.) On the visceral surface of the liver, locate the round ligament of the liver (and fissure), porta hepatis, the gallbladder, and ligamentum venosum (and fissure). You will likely need to view on a plastinated specimen, if there is little mobility in the liver.

Note: The remnants of the falciform ligament are present between the right and left lobes. The falciform ligament is a peritoneal reflection between the liver and the anterior abdominal wall, and to the inferior surface of the diaphragm (via the triangular ligaments). The falciform ligament contains the round ligament of the liver (the remnant of the umbilical vein). The round ligament of the liver sits in a fissure between the left lobe and quadrate lobe.

Photo 15: Anteroinferior view of the liver

Photo 16: Visceral surface of the liver with gallbladder

Note: The porta hepatis is a transverse fissure in the middle of the visceral surface of the liver. The porta hepatis transmits the neurovasculature and ducts of the visceral surface of the liver (hepatic arteries, hepatic portal vein, hepatic nerve plexus, lymphatics, and hepatic ducts).

Photo 17: Porta hepatis

Note: The ligamentum venosum and its fissure are located between the left lobe and caudate lobe. The ligamentum venosum is the remnant of ductus venosus (shunt between the inferior vena cava and the umbilical vein).

Photo 18: Visceral (inferior) surface of the liver

12.) Locate the diaphragmatic surface and the bare area of the liver.

Note: The bare area of the liver is the posterior portion of the diaphragmatic surface of the liver, and is the only portion of the diaphragmatic surface not covered with visceral peritoneum.

Photo 19: Diaphragmatic (superior) surface of liver

Uncover the contents of the biliary tract

Find these structures:

• Biliary tract

  • Right hepatic duct

  • Left hepatic duct

  • Common hepatic duct

  • Cystic duct

  • (Common) bile duct

13.) Using blunt dissection, uncover the contents of the hepatoduodenal ligament: the (common) bile duct, hepatic artery proper, and hepatic portal v.

Note: The hepatoduodenal ligament is a portion of the lesser omentum that connects the liver to the duodenum. It contains the (common) bile duct, the hepatic portal v., and the hepatic artery proper.

Photo 20. Hepatoduodenal ligament contents

14.) Using blunt dissection, identify the contents of the hepatoduodenal ligament, and continue to follow the (common) bile duct to its origin at the nexus of the cystic duct and common hepatic duct. Continue to trace the cystic duct to the gallbladder, and trace the common hepatic duct to its origin at the nexus of right and left hepatic ducts. Take caution to not damage any vasculature.

Note: The biliary tract begins with the right and left hepatic ducts which drain bile from their associated functional lobes of the liver. The hepatic ducts join to form the common hepatic duct. The cystic duct drains bile from the gallbladder, and joins the common hepatic duct to form the (common) bile duct.

Photo 21. Biliary tract

Locate and identify the spleen

Find this structure:

• Spleen

15.) Locate and incise the gastrosplenic ligament (part of the greater omentum). With blunt dissection, clear the ligament for a better view of the spleen.

Photo 22. Spleen, in situ

Dissect the celiac trunk and branches

Find these structures:

• Celiac Trunk

  • Left gastric a.

  • Common hepatic a.

    • Hepatic artery proper

      • Right gastric a.

      • Right br.

        • Cystic a.

      • Left br.

    • Gastroduodenal a.

      • Right gastro-omental (-epiploic) a.

        • Gastric brs.

        • Omental brs.

  • Splenic a.

    • Splenic brs.

    • Short gastric aa.

    • Left gastro-omental (-epiploic) aa.

      • Gastric brs.

      • Omental brs.

16.) Locate and incise the hepatogastric ligament (part of the lesser omentum).

17.) Locate the celiac trunk.

Note: The celiac trunk branches from the abdominal aorta at approximately the level of T12-L1 intervertebral disc, or just inferior to the aortic hiatus of the diaphragm. The trunk is very short and almost immediately branches into L. gastric a., common hepatic a., and splenic a.

Photo 23. Celiac trunk

18.) Identify the L. gastric a. Trace the artery towards the cardia of the stomach.

Note: The L. gastric a. anastomosis with the R. gastric a. along the lesser curvature of the stomach.

Photo 24. L. gastric a.

19.) Identify the common hepatic a. Around the level of the pylorus of the stomach (pyloroduodenal junction), the common hepatic a. splits into the hepatic artery proper and gastroduodenal a.

Photo 25. Common hepatic a.

20.) Follow the hepatic artery proper into the hepatoduodenal ligament. You must (gently) remove the peritoneum to get a better view of the vasculature in this area. Locate the R. gastric a., and follow this artery to the anastomosis point with the L. gastric a. at the lesser curvature of the stomach.

Photo 26. R. gastric a.

21.) Locate the right and left branches of the hepatic artery proper, which supply the liver.

Photo 27. Hepatic artery proper

22.) Locate the cystic a., which supplies the gallbladder.

Note: The cystic a. typically branches from the right br. of the hepatic a. proper, but it may also arise directly from the hepatic a. proper. Infrequently, the cystic a. arises from other brs. of the celiac trunk. The cystic a. is most easily located within the hepatobiliary triangle - a triangular area with borders of the common hepatic duct, the cystic duct, and the inferior surface of the right lobe of the liver. The hepatobiliary triangle is frequently confused with the triangle of Calot - a triangular area with borders of the common hepatic duct, the cystic duct, and the cystic a.

Photo 28. Cystic a. within the hepatobiliary triangle

23.) Locate the gastroduodenal a. as it branches from the common hepatic a. Clean and identify the R. gastro-omental a. (and its gastric and omental brs.) at the right portion of the greater curvature of the stomach.

Note: The gastroduodenal a. descends posterior to the junction between the stomach and duodenum. It has two major branches: superior pancreaticoduodenal a. and R. gastro-omental a.

Photo 29: Gastroduodenal a.

24.) Locate the splenic a., which branches from the celiac trunk and travels left lateral. Follow the splenic a. toward the hilum of the spleen, but be mindful to preserve branches of the splenic a. as they descend inferiorly into the pancreas. DO NOT REMOVE OR DISSECT THE PANCREAS AT THIS TIME. Locate the short gastric aa. and L. gastro-omental a. (and its gastric and omental brs).

Note: The large and tortuous splenic a. runs posterior to the superior portion of the pancreas. There are typically 4-5 short gastric aa., which will supply the fundus of the stomach. The L. gastro-omental a. supplies the left portion of the greater curvature of the stomach and anastomoses with the R. gastro-omental a.

Photo 30: Splenic a.

Photo 31: Splenic a., short gastric aa., L. gastro-omental a.

Observe the hepatic portal system

Find these structures:

• • Hepatic portal v.

  • Inferior vena cava (DEMO)

    • Hepatic vv. (DEMO)

25.) Locate the hepatic portal v. among the contents of the hepatoduodenal ligament, see as much of the hepatic portal v. and its major tributaries as possible without dissection; a more complete view of this system will be offered upon the dissection of the pancreas.

Note: Portal systems are vessels that link sets of capillary beds. The hepatic portal system is a venous portal system consisting of all veins that drain the gastrointestinal tract (GIT) from the abdominal esophagus to the superior rectum. These veins coalesce into the hepatic portal v. which delivers blood from the capillary beds of the GIT to capillary beds of the hepatic sinusoidal cells. As the hepatic portal system connects capillary beds, it is a separate system from the caval system (those veins which drain into the vena cavae). Blood from the hepatic sinusoidal cells is delivered back into the caval system via hepatic vv. draining into the inferior vena cava.

Note: The hepatic portal v. typically originates as a union of the superior mesenteric v. with the splenic v. in the transpyloric plane (approximately at L1), posterior to the neck of the pancreas. The hepatic portal v. ascends to the liver within the hepatoduodenal ligament with the common bile duct and the hepatic a. proper. These three elements are often referred to as the portal triad.

Photo 32: Hepatic portal system

26.) On a prosection or plastinated specimen, locate the hepatic vv.

Note: Typically, three (left, middle, & right) hepatic vv. drain blood of the liver to the inferior vena cava. These may be found draining into the portion of the inferior vena cava that passes through the fissure of inferior vena cava of the liver.

Locate nervous tissue associated with this area

Find these structures:

• Anterior vagal trunk

• Posterior vagal trunk

• Celiac plexus

27.) Locate the esophagus as it exits the esophageal hiatus of the diaphragm. Identify the anterior and posterior vagal trunks on the anterior and posterior surfaces of the esophagus. At the level of the celiac trunk, locate the celiac plexus.

Note: The celiac plexus is comprised of both sympathetic and parasympathetic fibers. The sympathetic fibers originate from the greater and lesser splanchnic nn. The parasympathetic fibers originate from the posterior vagal trunk.

Photo 33: Anterior and posterior vagal trunks