992 THE VASCULAE SYSTEM. 



between the layers of the lesser omentum, and along the lesser curvature of the stomach 

 with the left gastric artery, to the oasophagus, where it receives cesophageal tributaries. 

 It then turns posteriorly, in the left gastro-pancreatic fold, and reaches the posterior wall 

 of the abdomen, where it again changes its direction to run from left to right, behind 

 the omental bursa, to the right gastro-pancreatic fold, at the root of which it opens into 

 the portal vein. 



The right gastric vein is a small vessel which is formed by the union of tributaries 

 from the upper parts of both surfaces of the stomach. It runs from left to right along 

 the right portion of the lesser curvature, between the layers of the lesser omentum, and 

 terminates in the portal vein, after that vessel has entered the lesser omentum. 



Vena Cystica. The cystic vein is formed by the union of tributaries which 

 accompany the branches of the cystic artery on the anterior and posterior surfaces of the 

 gall-bladder; it ascends along the cystic duct and, as a rule, terminates in the right 

 branch of the portal vein. Some small veins pass directly from the gall-bladder into the 

 substance of the liver. 



THE MESENTERIC AND SPLENIC VEINS. 



Vena Mesenterica Superior. The superior mesenteric vein commences in the 

 right iliac fossa, in connexion with the lower part of the ileum. It ascends, along the 

 right side of the superior mesenteric artery, in the root of the mesentery, forming a 

 curve with the convexity to the left. 



As it ascends it passes anterior to the right ureter, the lower part of the inferior vena 

 cava, the third part of the duodenum, and the uncinate process of the head of the 

 pancreas ; and, after passing behind the root of the transverse mesocolon, it terminates, 

 behind the neck of the pancreas, by uniting with the splenic vein to form the portal vein. 



Its tributaries correspond with the branches of the superior mesenteric artery. It is formed 

 by the union of the ileo-caecal and appendicular veins. Anteriorly and towards the left side it 

 receives intestinal tributaries (venae intestinales) from between the layers of the mesentery ; the 

 right colic and ileo-colic veins enter its right side ; the middle colic vein joins it anterior to the 

 lower border of the head of the pancreas, and close to its termination it receives the right 

 gastro-epiploic and the pancreatico-duodenal veins. 



The right gastro-epiploic vein runs from left to right along the lower border of the stomach, 

 between the two anterior layers of the greater omentum. It receives tributaries from both sur- 

 faces of the stomach, and near the pylorus turns posteriorlv, in the right gastro-pancreatic fold of 

 peritoneum, passes in front of the neck of the pancreas, and ends in the superior mesenteric vein. 



The pancreatico-duodenal vein receives tributaries from the head of the pancreas and the 

 adjacent parts of the duodenum ; it ascends along the superior pancreatico-duodenal artery, and 

 terminates in the upper part of the superior mesenteric vein or in the portal vein. 



Vena Lienalis. The splenic vein is formed by the union of five or six tributaries 

 which issue from the hilum on the gastric surface of the spleen. It passes posteriorly 

 and medially, in the lieno-renal ligament, to the kidney, then, turning to the right, it runs 

 behind the upper border of the pancreas and below the splenic artery ; it crosses the front 

 of the abdominal aorta, immediately below the origin of the cceliac artery, and terminates, 

 behind the neck of the pancreas, by joining the superior mesenteric vein to form the 

 portal vein. 



Tributaries. It receives the vasa brevia or short gastric veins, the left gastro-epiploic vein, 

 the pancreatic veins, and the inferior mesenteric vein. Occasionally the coronary vein ter- 

 minates in it. 



The short gastric veins are a series of small venous channels which gather blood from the 

 region of the left portion of the greater curvature of the stomach ; they pass backwards towards 

 the spleen, in the gastro-splenic ligament, and terminate either in the trunk of the splenic vein 

 or in one of its main tributaries. 



The left gastro-epiploic vein runs from right to left along the lower border of the stomach 

 between the layers of the greater omentum. At the left extremity of the lower part of the greater 

 curvature of the stomach it enters the gastro-splenic ligament, through which it passes towards 

 the hilum of the spleen, and it terminates in the commencement of the splenic vein. It receives 

 tributaries from both surfaces of the stomach. 



The pancreatic veins issue from the substance of the pancreas, and terminate directly in the 

 splenic vein. 



The inferior mesenteric vein commences, as the superior haemorrhoidal vein, in the venous 

 plexus which lies between the muscular and mucous coats of the rectum. The superior 

 hsemorrhoidal vein drains the greater part of the blood from the hsemorrhoidal plexus, through 

 which it communicates with the middle and inferior hsemorrhoidal veins. It ascends, in com- 

 pany with the superior hsemorrhoidal artery and between the layers of the pelvic mesocolon, 



