8 Mr. C. B. Lockwood. The Arteries of the Abdomen. [Dec. 11, 



III. " On the Development of the Arteries of the Abdomen 

 and their Relation to the Peritoneum." By C. B. LOCK- 

 WOOD. Communicated by W. S. SAVORY, F.R.S. Received 

 November 18, 1884. 



(Abstract.) 



The paper begins by explaining that it records an endeavour to 

 elucidate the course and relations of the abdominal blood-vessels upon 

 developmental grounds. The earliest stages of the development of the 

 midgut and its mesentery are first described ; and it is shown that 

 vessels extend at very frequent intervals from the dorsal aorta to the 

 intestine, reaching the latter by way of the mesentery. The develop- 

 ment of the stomach is mentioned, and the gastric artery is identified 

 as one of the original arteries of the mesentery. The effects which 

 the various alterations in the position of the stomach have upon its 

 blood supply are discussed, and are considered to account for 

 peculiarities in the course of the gastric artery. The splenic artery is 

 reviewed next, and it is explained how both it and the spleen are deve- 

 loped between the layers of the mesogastrium ; evidence is adduced 

 to show that the vessel, even in the adult, reaches its destination by 

 passing through the mesogastrium, and it is maintained that this 

 fact determines the relations of the artery to the greater and lesser 

 cavities of the peritoneum. Next the very long arterial loops of the 

 great omentum are discussed ; as the omentum is nothing but the 

 elongated mesogastrium it is argued that they represent the original 

 vessels of that fold. The hepatic artery comes next, and the pro- 

 trusion of the liver from the midgut is described, and afterwards the 

 development of the lesser omentum. The hepatic artery is shown to 

 be one of the original arteries of the mesentery of that part of the 

 gut from which the liver grew. This fact is shown to explain the 

 relations of the vessel to the peritoneum and foramen of Winslow, 

 and also it is made use of to explain certain abnormalties of the 

 artery. It is pointed out that as the original function of the hepatic 

 artery in the embryo is to supply the bowel so it continues to afford 

 branches to it in the adult. The arteries of the small intestine and 

 pancreas are reviewed. With regard to the latter it is explained 

 how the organ is developed from the duodenum, and extends along 

 the mesoduodenum into the mesogastrium where it impinges upon 

 the spleen and its artery ; this, it is argued, accounts for the sources 

 of its blood supply. The manner in which the pancreas becomes 

 situated behind the peritoneum instead of between the layers is after- 

 wards attributed to the unfolding of the peritoneum between the 

 mesogastrium and the transverse mesocolon (i.e., the original 



