326 THE ANATOMY OF THE HORSE. 



The Gastric Trunk is the central of the three terminal branches 

 of the CQjliac 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-cesophageal Artery 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. 

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

 organ, beyond which it is continued as the left gastro-omental artery. 

 From its convex side it gives off many large splenic branches ; and from 

 its concave side it emits gastric branches, which pass in the gastro-splenic 

 omentum to reach the great curvature of the stomach, where they 

 bifurcate to be distributed to both surfaces of the left sac. 



The Left Gastro-omental Artery is the continuation of the splenic 

 artery beyond the tip of the spleen. It passes in the texture of the 

 great omentum to meet and inosculate with the right gastro-omental 

 artery, advancing in the opposite direction. Besides omental branches, 

 it emits gastric branches, which bifurcate at the great curvature of the 

 stomach to be distributed to both its surfaces. 



The Portal Vein (Plates 43 and 44) is the trunk which collects the 

 blood from the stomach, intestines, spleen, and pancreas, and conveys 

 it to the liver, where, as will afterwards be described in connection with 

 the liver structure, the vessel comports itself after the manner of an 

 artery. The vessel is formed behind the pancreas, by the junction of 

 the anterior mesenteric vein with a short trunk resulting from the union 

 of the posterior mesenteric and sple7iic veins. It gains the upper face of 

 the pancreas by passing through its substance, the perforation being 

 termed the piancreatic ring ; and, descending in the gastro-hepatic 

 omentum to the posterior fissure of the liver, it penetrates the substance 

 of the gland in company with the bile duct and hepatic artery. 



Anterior and Posterior Mesenteric Veins, satellites of the arteries of the 

 same names, have already been described ; but there is no venous trunk 



