Prelab Images - Stomach & Spleen

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. Remove the costal arch from the anterior aspect of the diaphragm. (Play movie)

Plate N276 or TG5-01 shows ribs 7-10 overlying the liver. You can saw through ribs 7-10 bilaterally and remove them. This will reveal the diaphragm and more of the structures within the abdominal cavity. Plate N266 or TG5-18 shows how the ribs and diaphragm will look after ribs 7-10 are removed.

Step 2. Examine the omental bursa and the derivatives of the dorsal and ventral mesogastria. (Play movie)

The lesser omentum and its hepatogastric and hepatoduodenal ligaments are all labeled in plate N275 or TG5-18. The omental (epiploic) foramen is labeled in plates N272 or TG5-18B and N275 or TG5-18A. This foramen leads into the omental bursa (lesser sac), which will be explored soon. Plate N277 or TG5-12A and TG5-12B shows the greater omentum. The part of the greater omentum that attaches to the colon is the gastrocolic ligament and the part that hangs over the small intestines is known as the omental apron. Plate N272 or TG5-18 labels the gastrosplenic, splenorenal, and gastrophrenic ligaments, which are all part of the greater omentum. Plates N272 or TG5-18 and N273 label the omental bursa (lesser sac). See the learning module for how this sac develops. Plates N348 and N331 or TG5-42 also show the omental bursa. Plate N271 or TG5-12B shows the transverse colon lifted up to expose the transverse mesocolon that you need to cut through in lab. After cutting through the transverse mesocolon you will be able to explore the omental bursa (lesser sac) from below and locate the stomach, spleen, pancreas, and posterior body wall in relation to the lesser bursa (N272 or TG5-18 and N273).

Step 3. Identify the parts of the stomach and expose the celiac artery. (Play movie)

Plate N275 or TG5-18 identifies the stomach and its parts: cardiac part, fundus, body, pyloric antrum, and pylorus. Plate N276 or TG5-19 shows the gastric rugae that you can observe on a plastinated specimen. Make a cut through the pylorus on your cadaver so you can observe the pyloric sphincter (labeled pylorus in plates N276 or TG5-19 and N277). Plate N275 or TG5-18 defines the lesser and greater curvatures of the stomach. Plates N232 or TG4-37 and N275 or TG5-18 label the abdominal esophagus passing into the stomach. Plates N276 or TG5-19 and N277 show the pyloroduodenal junction. After this junction the duodenum will move posteriorly and become retroperitoneal (plate N274 or TG5-26). Plate N272 or TG5-34 shows the celiac artery branching off of the abdominal aorta. This artery and its branching will be observed in the next step.

Step 4. Expose the branches of the celiac artery and define its branches to the stomach and spleen. (Play movie)

Plate N275 or TG5-18 shows the lesser omentum. Cut through the central part of the hepatogastric ligament to avoid damaging any vasculature. This will expose the omental bursa (N272 or TG5-18). The left gastric artery is identified in plate N300 or TG5-19 and the gastropancreatic fold it travels in is labeled in plate N272 or TG5-18. Trace this artery along the lesser curvature of the stomach and try to find gastric, esophageal, and possibly hepatic branches (the latter two will move superiorly off the left gastric artery, see plate N300 or TG5-19). The course of the accompanying left gastric vein is shown in plates N319 or TG5-19 and N312 or TG5-28. Plate N319 shows the hepatic branch of the anterior vagal trunk moving through the superior portion of the hepatogastric ligament. Be careful not to damage this while tracing the left gastric nerve. Plate N300 or TG5-19 shows the celiac trunk. Try to trace the left gastric nerve back to the celiac trunk. Plate N272 or TG5-18 shows the common hepatic artery in the right gastropancreatic fold (labeled peritoneal fold in N272 or TG5-18). Trace this artery from the vicinity of the celiac trunk until it divides into the proper hepatic and gastroduodenal arteries. Plate N275 or TG5-18 shows the hepatoduodenal ligament, which contains the proper hepatic artery. Plate N300 or TG5-19 shows the proper hepatic artery giving off the right gastric artery. Trace the right gastric artery to the lesser curvature of the stomach and see if you can trace it to where it anastomoses with the left gastric artery. Plate N348 or TG5-18 shows the celiac trunk behind the posterior body wall peritoneum sending vessels forward to supply structures of the abdominal cavity. Plate N300 or TG5-19 also shows the gastroduodenal artery giving off the posterior superior pancreaticoduodenal artery and then branching into the anterior superior pancreaticoduodenal artery and right gastro-omental arteries at the inferior border of the duodenum. Plate N300 or TG5-19 also shows the right gastro-omental (gastroepiploic) artery coursing along the greater curvature of the stomach and giving branches to the stomach and greater omentum. Plates N300 or TG5-19 and N show the relation of the celiac trunk to the pancreas. Plate N shows the origin of the splenic artery. Plate N272 or TG5-18 shows the splenic artery in the splenorenal ligament as it passes to the spleen. Plate N272 or TG5-18 also labels the gastrosplenic ligament. Plates N300 or TG5-19 and N show the splenic artery giving off branches to the pancreas (will be covered more later), splenic branches, short gastric arteries, and the left gastro-omental artery. Trace each of these vessels. Try to trace the left gastro-omental until it anastomoses with the right gastro-omental artery and find gastric and omental branches. Plate N301 or TG5-27 may also be helpful for reviewing some of the previously mentioned arteries.

Step 5. Examine the spleen, its mesenteric relations and the origin of the portal vein. (Play movie)

Plate N300 or TG5-19 shows the spleen. Plate N272 or TG5-18 reviews the splenorenal and gastrosplenic ligaments. Plate N276 or TG5-01 shows the location of the spleen in the abdominal cavity. Plates N300 or TG5-19 and N or TG5-27 show the blood supply to the spleen. The right gastric vein and portal vein are shown in plate N319 or TG5-28 and N312. Plate N275 or TG5-18 shows the hepatoduodenal ligament and plate N288 or TG5-24 shows the common bile duct, portal vein, and proper hepatic artery within the ligament (also see plate N300 or TG5-19 for the relation of these structures to each other). Plates N319 or TG5-19 and N312 or TG5-28 show the left and right gastric vein anastomosing to form the coronary vein.

Plates N or TG5-35A and N315 or TG5-35B show all the groups of lymph nodes listed: nodes around cardia, left gastric, celiac, (supra- and sub-) pyloric, gastro-omental, hepatic, pancreatic, and splenic. Plate N266 or TG5-37 also shows lymphatic drainage of the abdominal cavity.

Step 6. Expose the branches of the vagal trunks to liver, stomach, and celiac ganglion. (Play movie)

Plate N240 or TG4-45 shows the left vagus nerve forming the anterior vagal trunk and the right vagus nerve forming the posterior vagal trunk. Plate N319 shows the anterior vagal trunk giving off many small gastric branches and a large hepatic branch that travels in the lesser omentum to the liver and then inferiorly towards the duodenum (labeled as towards the pyloric part of stomach in Netter's). The hepatic branch may travel with a hepatic branch of the left gastric artery on its way to the liver. Plate N320 shows the posterior vagal trunk and its many gastric branches. Also find the branch of the posterior vagal trunk to the celiac plexus. Plate N126 or TG7-92 shows the entire distribution of the vagus nerve (you will see that it innervates the gastrointestinal tract all the way up to the left colic flexure). Plate N209 or TG4-45 shows the formation of the greater splanchnic nerve (T5-T9). Plates N320 and N321 or TG8-16 show that this nerve carries presynaptic sympathetic nerve fibers to the celiac plexus where they will synapse. The postsynaptic nerve will then distribute to the stomach. Plate N277 or TG5-12 shows the greater omentum and omental apron. Plate N272 or TG5-18 shows the ligaments of the greater omentum and plate N275 or TG5-18 shows the ligaments of the lesser omentum. Plate N273, N348, and N331 or TG5-42 may also be helpful to organize the mesenteries of the stomach.

 

 

Updated: 06 January 2012