THE ABDOMINAL CAVITY 



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possible to determine whether a loop of small intestine, drawn 

 out through an abdominal wound, belongs to the upper or lower 

 part of the canal. At the same time it is important that the 

 surgeon should be able to distinguish the proximal from the 

 distal end of such a loop. If its mesentery is not twisted in 

 any way this can be ascertained by tracing it back to the 





FIG. ioo. A Coil from the upper part of the Jejunum. The peritoneum 

 has been partially removed to show the arterial arcades. Compare the 

 appearance of the "windows" and the disposition of the fat in the 

 mesentery with Fig. 101. 



vertebral column the upper or left end of the loop on the surface 

 is also in reality its proximal end. 



The Superior Mesenteric Artery arises from the aorta 

 behind the pancreas and descends in front of the third part of 

 the duodenum. It then enters the root of the mesentery and 

 runs downwards and to the right at a distance of about half an 

 inch from the posterior abdominal wall. 



Close to its origin it gives off the inferior pancreatico-duodenal 

 artery, which runs to the right between the head of the pancreas 



21 a 



