316 THE ANATOMY OF THE HORSE. 



in company with the portal vein and the bile duct. At first imbedded 

 in the pancreas, it then passes over the duodenum, and reaches its des- 

 tination by passing between the layers of the gastro-hepatic omentum. 

 It crosses the posterior vena cava, from which it is separated by the 

 foramen of Winslow. It 'gives ofi^ the following collateral branches : — 



1. Pancreatic Branches. ! 



2. The night Gastro-omental Artery, which is, at its origin, of larger 

 volume than the continuation of the parent trunk, crosses behind 

 the duodenum ; and placing itself in the texture of the great omentum, 

 it is carried round the greater curvature of the stomach to inosculate with 

 the left gastro-omental artery. It gives off the pyloric and duodenal 

 arteries, besides numerous omental and gastric branches. The pyloric 

 ai-tery is detached from the right gastro-omontal artery near its origin, 

 and sometimes it is a branch of the hepatic artery. It supplies the 

 pylorus and the initial dilatation of the duodenum. The duodenal 

 artery is detached from the right gastro-omental artery before that vessel 

 crosses the duodenum ; and following the lesser curvature of the 

 duodenum, in the narrow serous band that fixes the bowel, it meets, 

 and inosculates with, the first artery from the left branch of the anterior 

 mesenteric artery. The omental hranches of the right gastro-omental 

 are small and unimportant. The gastric hranches pass from the 

 concave side of the parent artery ; and bifurcating at the greater 

 curvature, they are distributed to the right sac of the stomach on both 

 its surfaces, where they anastomose with branches of the pyloric and 

 gastric arteries. 



The Gastric Trunk is the central of the three terminal branches of 

 the ooeliac axis. After a course of a few inches downwards and forwards, 

 it bifurcates to form the anterior and posterior gastric arteries. 



The Anterior Gastric Artery reaches the anterior surface of the 

 stomach by crossing the lesser curvature immediately to the right of 

 the oesophagus. 



The Posterior Gastric Artery descends to the lesser curvature of the 

 stomach, where it divides into branches distributed on the posterior 

 aspect of the organ. 



The Pleuro-oesophageal Artei'y is a vessel constantly present, but 

 variable as regards its origin. It may arise from the gastric trunk or 

 one of its branches, or from the splenic artery. Passing through the 

 foramen sinistrum along with the oesophagus, it enters the thoracic 

 cavity, and there anastomoses with the oesophageal arteries, supplying 

 the pulmonary pleura at the base of the lung. 



The Splenic Artery is considerably larger than the gastric trunk or 

 the hepatic artery. Under cover of the pancreas, it passes outwards 

 between the left kidney and the cardiac extremity of the stomach. 

 Eeaching the spleen, it descends along the anterior border of that 



