CONNECTIONS OF INTESTINES. 433 



its surfaces looking forwards and backwards, and its borders upwards and 

 downwards ; but when distended, it becomes soirewhat circular, and makes 

 a rotatory movement, so as to bring forwards the border usually lowest, 

 and to turn upwards that surface which is directed forwards at other times. 



The position and connections of the stomach may be altered by varia- 

 tions in the size of any of the surrounding organs, or by the accumulation 

 of fluid in the chest, or in the belly. The stomach may be dragged down 

 likewise by the great omentum entering a hernia ; or it may be forced 

 down towards the pelvis by the pressure of tight stays. In these different 

 changes in position, the right end moves more than the left, because it is 

 attached mainly by peritoneum to the parts around. 



The small intestine (intestinum tenue) reaches from the stomach to the 

 right iliac region, where it ends in the large intestine. It is divided into 

 three parts, duodenum (twelve fingers' length), jejunum, and ileum : of- 

 the last two, the former receives its name from its empty condition, and 

 the latter from its numerous coils. 



The duodenum (h'g. 142, 1) cannot be satisfactorily seen at present, arid 

 it will be examined afterwards (p. 445). 



The Jejunum and ileum (fig. 143) begin on the left side of the second 

 lumbar vertebra, without any distinct mark of separation from the duode- 

 num. Two-fifths of the intestine belong to the jejunum, and the remain- 

 ing three-fifths to the ileum. 



This part of the intestinal tube forms many convolutions in the umbili- 

 cal, hypogastric, lumbar, and iliac regions of the abdomen ; and it de- 

 scends oftentimes, but more frequently in the female, into the cavity of tl.e 

 pelvis. In front of the convolutions is the great omentum. Beyond the 

 duodenum the intestine is fixed posteriorly to the spine by a process of 

 peritoneum named the mesentery, which contains the vessels and nerves. 

 Surrounding the jejunum and ileum is the large intestine or colon : but 

 on the left side of the body the colon is concealed by the small intestine. 



The large intestine, or the colon (fig. 142), is sacculated, and is more 

 fixed than the jejunum and ileum. It begins in the right iliac region in a 

 rounded part or head (caput caecum coli), and ascends to the liver through 

 the right iliac, lumbar, and hypochondriac regions. Crossing then the 

 abdomen below the stomach, it reaches the left hypochondriac region ; and 

 it lies in this transverse part of its course between the epigastric and um- 

 bilical regions, or altogether in the latter. Finally, it descends, on the 

 left side, through the regions corresponding with those it occupied on the 

 right, and forms a remarkable bend (sigmoid flexure) in the left iliac 

 fossa ; then becoming straighter it passes through the pelvis to end on the 

 surface of the body. 



It is divided into six parts, viz., caecum, ascending colon, transverse 

 colon, descending colon, sigmoid flexure, and rectum. 



The caecum (fig. 142,/") (caput caecum), or the commencement of the 

 colon, is placed in the right iliac fossa, in which it is fixed by the perito- 

 neum being stretched over it. In front usually are convolutions of the 

 small intestine, but when it is distended it touches the abdominal wall. 

 Behind, it rests on the iliac fascia, only fatty and areolar tissues interven- 

 ing. On the inner side it is joined by the small intestine ; and it presents 

 interiorly a worm-like piece the vermiform appendix. 



Sometimes the peritoneum surrounds the caecum, and attaches it by u 

 process to the abdominal wall. 



The ascending colon (fig. 142, a) reaches from the caecum to the under 

 28 



