662 BLOOD-VASCULAR SYSTEM OF THE HORSE 
renal, posterior mesenteric, and internal spermatic or utero-ovarian. The parietal 
branches are the lumbar arteries. 
I. The ceeliac artery (A. cceliaca) is an unpaired vessel, usually half an inch 
or less (ca. 1 em.) in length, which arises from the ventral aspect of the aorta at its 
emergence from the hiatus aorticus. It divides on the dorsal surface of the pan- 
creas into three branches—the gastric, hepatic, and splenic. 
1. The gastric artery (A. gastrica sinistra) passes downward and forward in 
the gastro-phrenic ligament, gives off cesophageal and pancreatic branches, 
and divides above and behind the cardia into anterior and posterior branches. 
The anterior branch (Ramus cranialis) crosses the lesser curvature just to the right 
of the cardia and ramifies on the parietal surface of the stomach. The branches 
pursue a flexuous course toward the greater curvature and anastomose with the 
short gastric arteries and the gastric branch of the hepatic artery. The pos- 
terior branch (Ramus caudalis) is distributed in a similar fashion on the visceral 
surface. The cesophageal branch (Ramus cesophageus) passes through the hia- 
tus cesophageus into the thoracic cavity above the cesophagus and anastomoses 
with the cesophageal branch of the broncho-cesophageal artery. 
The gastric artery often arises by a common trunk with the splenic. The two terminal 
branches may arise separately, or the anterior from the splenic and the posterior from the hepatie. 
The wsophageal branch often arises from the splenic or the posterior gastric. 
2. The hepatic artery (A. hepatica) is larger than the gastric. It passes for- 
ward and to the right and ventrally on the dorsal surface of the pancreas, covered by 
the gastro-pancreatic fold, crosses obliquely under the vena cava, and reaches the 
medial border of the portal vein. It divides into three or four branches which enter 
the portal fissure of the liver and ramify within the gland with the portal vein and 
the hepatic duct. It gives off the following collateral branches: (1) Pancreatic 
branches (Aa. pancreatic) are given off as the artery crosses the pancreas, in 
which it is partly embedded. (2) The pyloric artery (A. gastrica dextra) arises 
above the first curve of the duodenum. It descends to the pylorus, sending branches 
to the pylorus and the first part of the duodenum, and anastomoses with the gastri¢ 
and right gastro-epiploic arteries. It may arise from the gastro-duodenal. (3) 
The gastro-duodenal artery (A. gastroduodenalis) passes to the second curve of the 
duodenum and divides into the right gastro-epiploic and the pancreatico-duodenal. 
The right gastro-epiploic artery (A. gastroepiploica dextra) crosses over the posterior 
surface of the duodenum and enters the greater omentum, in which it runs to the 
left, parallel with the greater curvature of the stomach. It gives branches to the 
latter and to the omentum and forms an anastomotic arch with the left gastro- 
epiploic artery. The pancreatico-duodenal artery (A. pancreaticoduodenalis) 
divides into pancreatic and duodenal branches. The former (Ramus pancreaticus) 
supplies the middle part of the pancreas and is often replaced by a number of 
variable twigs. The duodenal branch (Ramus duodenalis) passes to the right along 
the lesser curvature of the duodenum and anastomoses with the first branch of the 
anterior mesenteric artery. 
Variations in the branching of the hepatic artery are not uncommon. The pancreatico- 
duodenal may arise directly from the trunk, and there may be a common trunk for the pyloric and 
right gastro-epiploic which runs along the dorsal surface of the first curve of the duodenum to the 
pylorus; here it gives off the small pylorie branch and is continued across the parietal surface of 
the pylorus as the right gastro-epiploic, no gastro-duodenal trunk being present. 
3. The splenic artery (A. lienalis) is the largest branch of the coeliac. It passes 
to the left (with the large satellite vein) on the left extremity of the pancreas and 
across the saccus czecus of the stomach. Entering the suspensory ligament of the 
spleen, it runs in the hilus of the spleen to the apex, beyond which it is continued 
as the left gastro-epiploic. It gives off the following branches: (1) Pancreatic 
branches (Rami pancreatici), which supply the left extremity of the pancreas. 
