ABDOMEN AND PELVIS 483 



The loops of the jejunum will be found in the superior half 

 of the regio mesogastrica and on each side of the vertebral 

 column ; the convolutions of the ileum are situated in the lower 

 half of the same region, in the regio hypogastrica, and in the 

 pelvis. The convolutions occupying the space between the two 

 psoas muscles are the most mobile. They are the most frequent 

 content in inguinal and femoral herniae. Determine the rela- 

 tions of the small intestine to the colon transversum and its 

 mesocolon above ; to the intestinum caecum and colon ascendens 

 on the right and colon descendens and colon sigmoideum on the 

 left; to the annulus inguinalis abdominalis and annulus femor- 

 alis below and lateralward, and to the urinary bladder, uterus, 

 and rectum in the median plane of the body. 



What factors are concerned in maintaining the loops of the 

 small intestine in their normal position ? What is enteroptosis ? 



Removal of the Intestines. 



Apply two ligatures around the upper end of the jejunum 

 about two inches below the flexura duodenojejunalis. Cut 

 between these. Cut through the blood-vessels and the remaining 

 fold of peritoneum of the mesentery along the line of their at- 

 tachment to the intestinal wall as far down as four inches above 

 the ileocaecal junction. Apply two more ligatures there and cut 

 between them. The intestine should now be taken to the sink, 

 the ligatures removed, and all contents of the bowel thoroughly 

 washed away. 



Remove a small piece of equal length from each end of the 

 intestine and weigh. Which is the heavier? Which has the 

 thicker walls? Feel them between the fingers. To what is the 

 greater thickness of the one due? Which is the more vascular? 

 Which has the larger lumen, the jejunum or the ileum? 



Remove about six inches from the upper part of the jejunum, 

 open it along its mesenteric border, and thoroughly clean the 

 mucous membrane. Spread it out carefully and pin it down 

 upon a cork dissecting tray, with the serous surface upward, and 

 study its coats. 



Coats of Small Intestine. 



(a) Serous coat (tunica serosa). 



(b) Muscular coat (tunica muscularis). 



(ba) Longitudinal layer (stratum longitudinale) . 



(bb) Circular layer (stratum circular e}. 



(c) Submucous coat (tela submucosa). 



