734 A MANUAL OF ANATOMY 



The hepatic flexure of the colon, and the right lobe of the liver. 

 Left. — ^The head of the pancreas, with the common bile-duct 

 behind, and the superior pancreatico-duodenal artery in front. 

 The common bile-duct and pancreatic duct enter the wall of this 

 part at the junction of the inner and posterior aspects, a little 

 below the centre. 



Third or Inferior Part. — This part extends from the right side of 

 the body of the third (sometimes fourth) lumbar vertebra to the 

 left side of the body of the second on a level with its upper border. 

 At this point it makes a sharp bend forwards, and terminates in 

 the jejunum, thus forming the duodeno- jejunal flexure. It lies at 

 first in the umbilical, and subsequently in the epigastric, region ; its 

 length is about 5 inches, and its direction is at first obliquely to 

 the left and upwards, and afterwards vertically upwards. Its 

 anterior surface is covered by peritoneum derived from the descend- 

 ing layer of the transverse meso-colon, except where it has the 

 superior mesenteric vessels in front of it. There is no peritoneum 

 behind it, and consequently it is fixed in position. 



Relations — Anterior. — The superior mesenteric vessels and the 

 upper part of the root of the mesentery, with portions of the small 

 intestine on either side of these. Posterior. — The inferior vena cava, 

 aorta (below the origin of the superior mesenteric artery), left renal 

 vein, left psoas magnus, and left crus of the diaphragm. Superior. — 

 The lower part of the head of the pancreas (mcluding its uncinate 

 process), and the inferior pancreatico-duodenal artery. 



The terminal portion of the third part is sometimes spoken of 

 as the fourth or ascending part of Treves. It is covered by peri- 

 toneum on the left side, as well as in front, and in cases where a 

 retro- duodenal fossa is present it is partially covered by peri- 

 toneum behind, towards the left side. The duodenal fossae of the 

 peritoneum are met with on the left side of this portion. The 

 duodeno- jejunal flexure is suspended from the left crus of the 

 diaphragm by a fibro-muscular bundle, called the musculus sus- 

 Pensorius duodeni. 



Blood and Nerve Supply of the Duodenum. — ^The arteries of the 

 duodenum are as follows: (i) The pyloric branch of the hepatic; 

 (2) the superior pancreatico-duodenal branch of the gastro-duodenal 

 of the hepatic; and (3) the inferior pancreatico-duodenal branch of 

 the superior mesenteric. 



The veins terminate in the superior mesenteric and splenic veins. 



The nerves are derived from the hepatic and superior mesenteric 

 sympathetic plexuses. 



The lymphatic vessels of the first part of the duodenum pass to the 

 retro-pyloric glands, and those of the second and !hird pa.Tis pass to 

 the pre-pancreatico-duodenal and retro-pancrcatico-duodenal glands. 



Position and Connections of the Pancreas. — The pancreas is a 

 long narrow gland which is situated behind the stomach, on a level 

 with the first and second lumbar vertebrae. Its right extremity 

 occupies the duodenal curve, and its somewhat pointed left ex- 



