484 ABDOMEN 



arteries pass into the pelvic meso-colon, and there form a 

 series of arcades, varying in number according to the length 

 of this mesentery, from which the twigs for the supply of the 

 pelvic colon are given off. 



The superior hamorrhoidal artery will be followed out in 

 the dissection of the pelvis. 



Vena Mesenterica Inferior. This vein receives tributaries 

 corresponding with the branches of the inferior mesenteric 

 artery. It passes upwards, upon the psoas magnus muscle, 

 under cover of the peritoneum, to the left of, and at some 

 distance from, the artery, and, disappearing behind the 

 pancreas, it ends in the splenic vein. 



Plexus Mesentericus Inferior. This plexus of nerve fibres 

 is an offshoot from the left side of the aortic plexus. It 

 closely surrounds the artery, and sends twigs along the 

 branches of the vessel to supply the left half of the large 

 Intestine. 



Plexus Aorticus Abdominalis. The aortic nerve plexus 

 is placed upon the aorta between the origins of the two 

 mesenteric arteries. It is more strongly marked upon the 

 sides of the artery than in front of it. Superiorly it is 

 continuous with the cceliac and renal plexuses, but this 

 fact must be demonstrated at a later stage of the dissection, 

 whilst inferiorly it sends several large branches downwards, 

 in front of the common iliac arteries, to join the hypogastric 

 plexus a plexus which is situated in front of the fifth lumbar 

 vertebra. Upon each side the aortic plexus will be observed to 

 be reinforced by several small twigs from the gangliated cord of 

 the sympathetic. The inferior mesenteric plexus accompanying 

 the artery of that name, and the internal spermatic (or ovarian) 

 plexus of nerves which accompanies the internal spermatic 

 (or ovarian] artery, are offsets from it. 



Removal of the Jejunum and Ileum. Apply two ligatures round the 

 jejunum about an inch below the duodenal flexure and divide the gut 

 between them ; next place two ligatures round the ileum about six inches 

 above its union with the large intestine, and divide it in like manner ; then 

 cut through the blood-vessels and the remains of the mesentery close to the 

 wall of the gut and remove the separated portion. When they have been 

 detached the jejunum and ileum should be taken to the sink, the ligatures 

 should be removed, and the cavity of the separated portion of the gut should 

 be thoroughly cleaned by allowing water from the tap to run through it. 



The coats of the small intestine should be dissected under water. Take 

 a few inches from the upper end of the jejunum, and, having opened it up 

 with the scissors along the mesenteric line of attachment, pin it out, with 



