252 PRACTICAL ANATOMY. 



cystic artery to the gall-bladder ; its pyloric branch to meet the gastric ; its 

 superior pancreatico-duodenal branch downward behind the duodenum ; here one 

 branch follows the second part of the duodenum and anastomoses with the 

 inferior pancreatico-duodenal branch of the superior mesentcric artery ; the other 

 follows the greater curvature of the stomach and, under the name of right gastro- 

 epiploica, anastomoses with the left gastro-epiploica, a branch of the splenic 

 artery. Finally, trace the main branch of the hepatic artery to the transverse 

 fissure of the liver. 



The portal vein lies between the common duct and. the hepatic artery. (Fig. 

 1 77.) It is formed by veins from the abdominal organs of digestion. Its blood is 

 laden with bile, glycogen, and urea. The bile is stored up in the gall-bladder ; 

 the glycogen is stored up in the liver ; the urea is thrown off. Find the hepatic 

 veins discharging into the ascending vena cava, as this vessel passes through the 

 diaphragm. 



The hepatic veins take all blood from the liver brought to that organ by 

 the hepatic artery and portal vein. The vein discharges into the ascending vena 

 cava, just as that vessel is passing through the diaphragm. 



The Greater and Lesser Peritoneal Cavities. A knowledge of these cavi- 

 ties must be gained by study of the evolution of the peritoneum and alimentary 

 canal, from a straight gut and single simple mesentery. (See Morris.) The 

 foramen of Winslovv connects all the cavity you can see thus far, with the lesser 

 cavity, behind the stomach. By mechanical devices your teacher will demon- 

 strate the modus operandi of rotation, and this demonstration will interpret the 

 description given in the larger text. Permit me to add in this place that tvery 

 organ, with all its adnexa, grows up behind peritoneum, pushes this ahead of 

 itself, and thereby becomes invested by the same, partially or completely. 



To Dissect the Duodenum. Thoroughly inflate the stomach and duodenum, 

 as previously directed. Then divide the gastro-colic omentum and turn the 

 transverse colon down toward the pelvis. Lift the stomach up, and observe the 

 lesser cavity of the peritoneum behind the same. In cutting the great omentum, 

 care must be taken not to injure the arteries along the greater curve of the 

 stomach. (Fig. 174.) Now remove the colon from the second stage of the duo- 

 denum. The stages of the duodenum are : (i) From the pylorus of the stomach 

 to the gall-bladder, two inches ; (2) from the gall-bladder to the hiluni of the 

 kidney, three inches; (3) from the hilum of the kidney to the duodeno-jejunal 

 angle, five inches. These stages are called ascending, descending, and trans- 

 verse, respectively. 



Relations of Transverse Duodenum. You will find, above, the superior 

 mesenteric vessels and the head of the pancreas ; in front, the superior mesen- 

 teric vessels, the mesentery, and small intestine. Behind you will now dissect 

 down with the forceps, and find the aorta, vena cava inferior, the crura of the 

 diaphragm, and the fourth lumbar vertebra. On the left, the transverse duode- 

 num terminates in the jejunum ; on the right, in the descending duodenum, on 

 the middle one-third of the kidney. 



The Pancreas and Splenic Artery. A very careful dissection of the pan- 

 creas must be made. The organ is delicate. It lies behind the stomach (Fig. 180) ; 

 hence turn the stomach up to expose the same. Steps : (i) Locate the splenic 

 artery by gently lifting the upper border of the pancreas. Follow the artery to 

 the spleen. You will now find it necessary to divide the gastro-splenic omentum, 

 but in doing this do not injure the arteries ! Notice and save the pancreatic 

 arteries, large and small, given to this organ the pancreas by the splenic artery. 

 Trace out the branches given to the stomach. Find the gastro-epiploica sinistra 

 artery. (2) Now dissect out the head of the pancreas. Trace the superior pan- 

 creatico-duodenal artery between the pancreas and the duodenum, taking notice 



