

THE PERITONEUM. 979 



We may say that the peritoneum has two surfaces, i. e. one attached to the 

 wall or visciis and the other is free and shiny : there are two layers, parietal and 

 visceral, and two sacs, since the large one has a posterior subdivision formed when 

 the stomach rotated to the right in the embryo. 



The various folds and bands formed by the peritoneum in passing from the 

 different viscera or walls have definite names. 



An Omentum means a fold of peritoneum which connects the stomach with 

 other viscera, viz. great and gastro-colic amentum, small or gastro-hepatic, and 

 i/'i."tro-sp!enic. These are situated respectively below, above, and to the left of 

 the stomach. 



A Mesentery is a fold of peritoneum connecting any part of the small intestine 

 to the posterior wall. It is used also in a wider sense. The name of the fold 

 connecting any part of the alimentary canal below the oesophagus to vertebral 

 column or posterior abdominal wall may be found by prefixing the Greek adjective 

 mesos (usaoz) or Latin medium to the Greek or Latin name of the part fixed, as 

 itixtriuii). me*''luf>fl>:num, mesentery, mesenteriolum (little mesentery for ver- 

 miform appendix). There is no mesocaecum in the adult, but sometimes an 

 ascending or descending mesocolon ; always a transverse mesocolon, a sigmoid 

 mesocolon. and a mesorectum. 



Ligament is a term applied to folds connecting viscera not belonging to the 

 intestinal canal, to the abdominal walls, or to folds which bind viscera to the 

 diaphragm. The German anatomists apply this term also to omenta. There 

 are ligaments of the bladder, uterus, and liver, and others, as lieno-renal, hepato- 

 renal, and gastro-phrenic. 



We will now trace the peritoneum in a vertical direction simply to show its 

 continuitv and to see from a side view how it surrounds viscera or forms bridges 

 from one organ to another (Fig. 606). 



We may begin anywhere, perhaps best at a point above the liver, where the 

 parietal layer of peritoneum is reflected from the diaphragm to the liver, becoming 

 visceral layer. 



The student is supposed to have read carefully all the description of the 

 peritoneal development. Now he follows by hand the parts in the subject and 

 the diagram by eye. Lifting up the diaphragm the hand passes over the glisten- 

 ing superior surface of the liver in the middle line till it is stopped posteriorly 

 by a fold called the coronary ligament. The peritoneum covers all the surface 

 of the liver to its anterior acute margin. Next lift up the liver from the stomach 

 and trace the layer backward on the under surface of the liver to the transverse 

 fissure or hilus. and the hand is again stopped, this time by the peritoneum 

 ending to the lesser curvature of the stomach, making one layer of the lesser 



ntum ; or, giving the names of the viscera connected, hepato-gastric amentum . 

 This layer now covers the anterior surface of the stomach and reaches the greater 

 curvature ; here it falls directly downward to a varying extent, usually to the 

 pubic region, making the anterior superficial layer of the great amentum. Just 

 below the stomach the transverse colon may be seen shining through. This 

 layer in the foetus and young child should not be attached to it, however. Now lift 

 up the great omentum over the stomach and this layer may be seen to be reflected 

 up to the under surface of the transverse colon, making the posterior superficial 

 layer of the great omentum. Fig. 602 shows that the great omentum has not 

 always been present ; this layer we are now tracing used to pass above the trans- 

 verse colon and go to the pancreas and then return, making two layers. Fig. 603 

 shows how these two layers united into one ; and Fig. 606 shows how one has 

 disappeared as such, and how this layer passes beneath the "transverse colon and 

 on to the vertebral column and anterior margin of the pancreas, making the 

 lower layer of the transverse mesocolon. 



This laver is closelv connected with the vertebral column, aorta, and vena cava 



* 



inferior, and on leaving the pancreas meets the superior mesenteric vessels and 

 surrounds them. It covers only anteriorly the pre-aortic portion of the duode- 



