THE SMALL INTESTINES 189 



bladder. The ist inch is invested with peritoneum, but the 

 2nd inch is covered in front only. 



In front. Liver, gallbladder. 



Behind. Bile - duct, 'vena portae, hepatic artery, gastro- 

 duodenal artery. 



Below. Head of pancreas. 



2nd part : 3^ inches long ; is vertical ; passes from opposite 

 neck of gall-bladder down to 3rd lumbar vertebra. Ducts of 

 liver and pancreas enter this part. Covered in front by 

 peritoneum. 



In front. Transverse colon, liver and gall-bladder, small 

 intestines. 



Behind. Right kidney, supra-renal capsule, renal vessels, 

 and inferior vena cava. 



Left side. Head of pancreas, common bile - duct, and 

 pancreatic duct. 



Right side. Hepatic flexure of colon. 



On the inner aspect, 3^ or 4 inches from the pylorus, is 

 the bile papilla, on which is the orifice for both the common 

 bile and pancreatic ducts. 



3rd part : about 4^ inches long ; passes from right to left 

 across spine, ascending from 3rd to and lumbar vertebra, 

 ends in jejunum on left side of spinal column ; lies below 

 transverse meso-colon, and is covered in front by peritoneum, 

 except where root of mesentery crosses it. 



In front. Superior mesenteric vessels and plexus. 



Behind. Aorta, inferior vena cava, crura of diaphragm, left 

 psoas, and left renal vessels. 



Above. Pancreas. 



ARTERIES. Pyloric, and superior pancreatico-duodenal of 

 hepatic, inferior pancreatico-duodenal of superior mesenteric. 



NERVES, from solar plexus. 



THE JEJUNUM AND ILEUM. 



The jejunum forms f of the rest of the small intestines, 

 which are 23 feet long ; commencing on the left side of the 

 2nd lumbar vertebra, it terminates in the ileum ; it is wider, 

 and its coats are thicker, more vascular, and of a deeper 

 colour than the ileum. 



The ileum consists of the remaining f of the small intestines, 

 and terminates in the right iliac fossa by opening into the caecum. 



The ileum with the jejunum is suspended from the posterior 

 abdominal wall by the mesentery (p. 196). The vessels are 

 derived from the superior mesenteric artery, and the veins 

 drain into the vein of the same name. 



