Approaching the spleen, the splenic artery gives off short gastric arteries, which pass through the gastrosplenic ligament to supply the fundus of the stomach. It also gives off the left gastro-omental artery, which runs to the right along the greater curvature of the stomach, and anastomoses with the right gastro-omental artery.
The common hepatic artery is a medium-sized branch of the celiac trunk that runs to the right and divides into its two terminal branches, the hepatic artery proper and the gastroduodenal artery (Figs. 4.123 and 4.124).
The hepatic artery proper ascends toward the liver in the free edge of the lesser omentum. It runs to the left of the bile duct and anterior to the portal vein, and divides into the right and left hepatic arteries near the porta hepatis (Fig. 4.125). As the right hepatic artery nears the liver, it gives off the cystic artery to the gallbladder.
The right gastric artery often originates from the hepatic artery proper but it can also arise from the common hepatic artery or from the left hepatic, gastroduodenal, or supraduodenal arteries. It courses to the left and ascends along the lesser curvature of the stomach in the lesser omentum, supplies adjacent areas of the stomach, and anastomoses with the left gastric artery.
The gastroduodenal artery may give off the supraduodenal artery and does give off the posterior superior pancreaticoduodenal artery near the upper border of the superior part of the duodenum. After these branch the gastroduodenal artery continues descending posterior to the superior part of the duodenum. Reaching the lower border of the superior part of the duodenum, the gastroduodenal artery divides into its terminal branches, the right gastro-omental artery and the anterior superior pancreaticoduodenal artery (Fig. 4.124).
The right gastro-omental artery passes to the left, along the greater curvature of the stomach, eventually anastomosing with the left gastro-omental artery from the splenic artery. The right gastro-omental artery sends branches to both surfaces of the stomach and additional branches descend into the greater omentum.
The anterior superior pancreaticoduodenal artery descends and, along with the posterior superior pancreaticoduodenal artery, supplies the head of the pancreas and the duodenum (Fig. 4.124). These vessels eventually anastomose with the anterior and posterior branches of the inferior pancreaticoduodenal artery.
The superior mesenteric artery is the anterior branch of the abdominal aorta supplying the midgut. It arises from the abdominal aorta immediately below the celiac artery (Fig. 4.126), anterior to the lower part of vertebra LI.
The superior mesenteric artery is crossed anteriorly by the splenic vein and the neck of the pancreas. Posterior to the artery are the left renal vein, the uncinate process of the pancreas, and the inferior part of the duodenum. After giving off its first branch (the inferior pancreaticoduodenal artery), the superior mesenteric artery gives off jejunal and ileal arteries on its left (Fig. 4.126). Branching from the right side of the main trunk of the superior mesenteric artery are three vessels—the middle colic, right colic, and ileocolic arteries—which supply the terminal ileum, cecum, ascending colon, and two-thirds of the transverse colon.