284 ABDOMEN 



artery to its origin from the hepatic artery and follow the latter 

 upwards, in the right border of the lesser omentum, to its division 

 into right and left branches immediately below the porta hepatis. 

 On the walls of the artery some of the fibres of the hepatic 

 plexus of sympathetic nerves may be recognised, and at its side 

 some of the biliary lymph glands may be seen. Clean both 

 terminal branches of the hepatic artery carefully, especially 

 the right branch, which passes either anterior or posterior to 

 the hepatic duct. To the right of the hepatic artery find the 

 bile duct ; trace it downwards to the point where it disappears 

 behind the first part of the duodenum, and upwards to the upper 

 border of the lesser omentum, where it is formed by the union 

 of the common hepatic duct with the cystic duct. Follow 

 the cystic duct to the neck of the gall-bladder, noting that it 

 makes an S-shaped bend. Continue the incision already made 

 in the gall-bladder into the cystic duct and note that the spiral 

 arrangement of the mucous membrane is continued into the 

 duct. Follow the common hepatic duct upwards into the 

 porta hepatis, to the point where it is formed by the union of 

 the right and left hepatic ducts, which come respectively from 

 the right and left lobes of the liver. Clean away the areolar tissue 

 from between the hepatic artery and the bile duct and display 

 the portal vein, which lies behind them. Trace it upwards to 

 its division into right and left branches at the porta hepatis, 

 and downwards to the first part of the duodenum, where it dis- 

 appears from view at the present stage of dissection. Note 

 that the portal vein lies immediately in front of the epiploic 

 foramen "(Winslow), and that its posterior surface is covered 

 by the peritoneum of the anterior margin of the foramen. 



Omentum Majus (The Greater Omentum). After the 

 dissector has displayed and studied the structures situated 

 between the two layers of the lesser omentum he should 

 examine the greater omentum, which hangs down, like an 

 apron, in front of the viscera which lie in the lower part of the 

 abdomen. It is a double fold of peritoneum and consists, 

 therefore, of two anterior and two posterior layers, the former 

 being separated from the latter by a portion of the cavity of 

 the omental bursa. The upper margins of the anterior two 

 layers are attached to the lower part of the greater curvature 

 of the stomach, where they become continuous with the peri- 

 toneum on the anterior and posterior surfaces of that viscus. 

 To the left and above, the anterior two layers are continuous 

 with the two layers of the gastro- splenic ligament, but at a 

 lower level the anterior two layers become continuous with the 

 posterior two layers at the free left border. Similarly at the 

 lower and the right margins of the greater omentum the anterior 

 two layers become continuous with the posterior two layers. 

 The upper margins of the posterior two layers are attached 

 to the lower border of the transverse colon, and, through the 



