432 SPLANCHNOLOGY, OR ANATOMY OF THE VISCERA 



The Jejunum and Heum 



The jejunum includes the first two-fifths of the remaining 

 part of the small intestine, running from the left side of the 

 first or second lumbar vertebra to the beginning of the ileum, 

 and occupying the umbilical and left lumbar and iliac regions. 

 Its coats are thicker and more vascular, and is of a deeper 

 color and larger caliber than the ileum. 



The arteries supplying the jejunum are derived from the 

 superior mesenteric and are called the arteria intestine tenuis. 

 They are arranged in loops between the mesentery; single 

 loops near the beginning, then double and even tertiary loops 

 are seen as the ilium is approached. The veins correspond 

 to the arteries and empty into the superior mesenteric vein, 

 which unites with the splenic to form the portal. There are 

 no valves in the mesenteric veins. 



The nerves are derived from the celiac axis (sympathetic) 

 and some from the vagus. The plexus of Auerbach is found 

 in the muscular coat, and Meissner's plexus is situated in the 

 submucous coat, and is made up from filaments of the celiac 

 plexus and vagus. The lymphatics pass to the mesenteric 

 nodes, between the layers of the mesentery. 



The remainder of the small intestine is the ileum, which 

 ends by opening into the inner side of the commencem-Mit 

 of the large gut in the right iliac fossa. Its coils occupy the 

 hypogastric, umbilical, and right lumbar and iliac regions. 



THE LARGE INTESTINE 



The large intestine is that part of the alimentary canal 

 which extends from the end of the ileum to the anus; it is 

 about 5| feet long. It commences by a dilated part, the cecum, 

 in the right iliac fossa, ascends to the under surface of the 

 liver, then runs transversely across the abdomen to the vicinity 

 of the spleen, descends to the left iliac fossa, and forms the 

 sigmoid flexure, and finally passes along back of the pelvis 

 to end at the anus. 



The cecum is the large cul-de-sac which is the beginning of 

 the large intestine, and is about 3 inches broad and 2| inches 

 long. It is variously situated, being found on the psoas, external 



