24 DISSECTION OF THE DOG 



porta of the liver. Here onee again the layers separate, this time to form the 

 serous investment of the liver. The continuation of the most ventral layer 

 of the lesser omentum follows the caudal surface of the liver, crosses its ventral 

 border and proceeds to the diaphragmatic surface, from which it is reflected 

 onto the diaphragm, and thence can be followed along the ventral wall of the 

 abdomen to the pelvis. The more dorsal of the two layers of the lesser 

 omentum, in like manner, is continued onto the liver and from this organ to 

 the diaphragm and the dorsal wall of the abdomen. 



If the two dorsal layers of the greater omentum are followed towards the 

 dorsal Avail of the abdomen, they will be found to enclose the left limb of the 

 pancreas before arriving at the wall itself. On the Avail the tAvo layers separate. 

 One becomes confluent with the continuation of the more dorsal layer of the 

 lesser omentum. The other passes into the transverse mesocolon ; that is to 

 say, it leaves the dorsal abdominal Avail, surrounds the transA^erse colon and 

 again returns to the Avail of the abdomen. Here it is continuous with the root 

 of the mesentery (radix mesenterii). 



Beyond this point the peritoneum proceeds along the abdominal Avail into 

 the peMs and finally becomes that part of the membrane already followed 

 along the ventral abdominal Avail. 



From Avhat has just been said, it is clear that a compartment of the peritoneal 

 cavity is enclosed within the greater omentum. Consequent upon its associa- 

 tions, this is known as the omental bursa (bursa omentalis). The communication 

 betAveen the main peritoneal cavity, entered Avhen the abdomen Avas first 

 opened, and the omental bursa, is by means of a comparatively small orifice, 

 the epiploic foramen of Winslow (foramen epiploicum [WinsloAAi]). To find the 

 foramen, pull the duodenum over toAvards the left and look for the caudate 

 process of the liA^er, which will be readily recognised as that part of the liA^er 

 which is in contact with the right kidney. If iioav the index finger of the left 

 hand be passed along the caudate process toAvards the middle line it Avill enter 

 the epiploic foramen. The right hand should be introduced into the omental 

 bursa through an opening in the omentum, and the epiploic foramen sought 

 from the left side. 



The greater part of the omental bursa is contained in that part of the 

 greater omentum which covers the intestine. The rest of it is continued 

 doi'sal to the stomach, and between this organ and those two dorsal layers of 

 the omentum which contain the left limb of the pancreas. The boundaries 

 of the bursa are^formed as follows : Yentrally, by the ventral layers of the 

 omentum, by the stomach, by the lesser omentum, and by the omental process 

 of the liver ; dorsally, by the dorsal layers of the greater omentum and the 

 pancreas ; on the left, by the spleen and the gastro-lienal ligament (ligamentum 

 gastro-lienale) which connects the greater curvature of the stomach and the 

 hilus of the spleen, and is directly continuous with the ventral layers of the 

 greater omentum. 



