THE PERITONEUM. 



1741 



Diaphragm 



support, we can imagine it suspended in the middle by a series of cords which might 

 be all enclosed in one fold of paper from the ceiling. This would be a mesentery and 

 the cords would be blood-vessels going to the gut. The cords, of course, would be 

 on the wrong side of the paper and the vessels on the areolar side of the mem- 

 brane. A fold of peritoneum may contain large vessels and strong bundles of fibres, 

 and at other places be no more than a duplicature of membrane. The former are 

 the mesenteries and certain bands called "ligaments," the latter plica or folds. 

 The complications of the 



peritoneum are reduced FIG. 1467. 



as much as possible by 

 studying it in the light of 

 development, the account 

 of which has been already 

 given (page 1702). Here 

 only some of the chief 

 points and general prin- 

 ciples are recapitulated. 



In the early foetus the 

 peritoneum is merely the 

 lining of the abdomen, 

 the parietal peritoneum, 

 which covers the Wolffian 

 bodies and the beginning 

 of the abdominal walls, 

 and certain median folds 

 called mesenteries, con- 

 veying blood-vessels to 

 the gut, within which cer- 

 tain accessory organs are 

 developed. There is a 

 posterior mesentery ex- 

 tending from the spine to 

 the whole length of the 

 alimentary canal below 

 the diaphragm, to which 

 it carries vessels from the 

 aorta, and an anterior 

 mesentery running to the 

 upper part of this canal 

 from the anterior abdom- 

 inal wall (Fig. 1432). 

 The original posterior 

 mesentery is divided into 

 three regions, each of 

 which conveys a particu- 

 lar artery, i. The mesen- 

 tery of the stomach and 

 of the duodenum, con- 

 taining the cceliac axis. 

 It is to be noted that this 

 region may be subdivided 



into two parts, the upper formed by the stomach and the first part of the duodenum, 

 the lower formed by the remainder of the duodenum. The latter originally arches 

 forward, both ends being fixed at the spine. 2. The mesentery of the rest of the 

 small intestine and of the ascending and the transverse colon, containing the superior 

 mesenteric artery. 3. The mesentery of the remainder of the large intestine, con- 

 taining the inferior mesenteric artery. 



The anterior mesentery, in which the liver is developed, reaches the stomach 

 and the upper part of the duodenum, extending on the anterior wall as low as the 



Diagram showing general arrangement of peritoneum, which is represented 



by the black line ; arrow passes from greater into lesser sac through foramen 

 of Winslow. L, liver; S, stomach; P, pancreas; D, duodenum; TC, trans- 

 verse colon ; /, small intestine ; K, rectum ; B, bladder ; U, uterus. 



