Vascular Anatomy

The pancreas receives blood supply from multiple branches of the celiac axis and the SMA.5-8 The head of the pancreas is supplied by a network of arteries that originates from three major arteries (Fig. 12-1). The gastroduodenal artery (GDA) descends from the common hepatic artery (CHA) in the retropyloric space between the pylorus and the cranial portion of the head of the pancreas. Proximally, it gives off a branch posteriorly that runs along the posterior lateral surface of the pancreatic head along the common bile duct, the posterior superior pancreaticoduodenal artery (SPDA). The GDA continues its course in the craniocaudal direction anterior to the head of the pancreas and then bifurcates to form a branch coursing anteriorly in the gastrocolic ligament to become the right gastroepiploic artery, which runs along the greater curvature of the pylorus. The other branch continues in the craniocaudal direction close to the anterior surface of the pancreas as the anterior SPDA. The posterior and anterior SPDAs then form an anastomotic network around the head of the pancreas with the inferior pancreaticoduodenal artery (IPDA) and a branch of the dorsal pancreatic artery.

The IPDA arises from the proximal jejunal artery or directly from the SMA. These arteries usually originate from the posterior wall of the SMA. The IPDA gives off a few small branches to the uncinate process and gives off a branch posteriorly to join the posterior SPDA and another branch anteriorly to join the anterior SPDA.

The dorsal pancreatic artery originates from the posterior or caudal surface of the celiac axis or the proximal 1-2 cm of the common hepatic or splenic artery. It can be identified behind the proximal portion of the body of the pancreas. It usually gives off a branch to the right, medial to the cranial portion of the head of the pancreas and the portal vein. This branch runs medially along the head of the pancreas and anastomoses with the peripan-creatic arcade around the head of the pancreas.

The body and tail of the pancreas receive their blood supply from the dorsal pancreatic artery and multiple branches along the course of the splenic artery. The dorsal pancreatic artery courses along the body and tail and anastomoses with small branches from the splenic artery.

The venous drainage of the head of the pancreas forms a network around the head and follows a branching pattern similar to the artery (Fig. 12-2). The anatomy of these veins is relatively constant, but the course of the veins and their drainage patterns differ from the artery. The confluence of the SMV and the splenic vein forms the portal vein. The relationship of these three veins with the pancreas is most important in pancreatic surgery. The segment of the SMV at the caudal portion of the head of the pancreas receives two important

Fig. 12—2. Illustration of the venous anatomy of the pancreas.

1 = portal vein; 2 = splenic vein; 3 = superior mesenteric vein; 4 = inferior mesenteric vein; 5 = posterior superior pancreaticoduodenal vein (SPDV); 6 = anterior SPDV; 7 = inferior pancreaticoduodenal vein; 8 = right colic vein.

Waveform For Right Anterior Portal Vein

branches that are closely associated with the uncinate process and the head, the proximal jejunal vein, and the gastrocolic trunk. The proximal jejunal vein that drains the proximal segment of the jejunum frequently drains into the SMV posteriorly. Before it enters into the SMV, it picks up the drainage from the inferior pancreaticoduodenal vein (IPDV). The gastrocolic trunk, which is formed by the right gastroepiploic vein, the middle colic vein, and the right colic vein, runs in the gastrocolic ligament and drains into the SMV anteriorly. The posterior superior pancreaticoduodenal vein (SPDV) follows the bile duct and drains into the caudal surface of the main portal vein within 2 cm of the confluence of the SMV and splenic vein, in most cases. The anterior SPDV is a smaller vein that runs horizontally along the anterior surface of the head of the pancreas before joining the gastrocolic trunk and draining into the SMV.

At the confluence of the SMV and the splenic vein that forms the portal vein, the inferior mesenteric vein may join the portal vein in this region; 60-70% join the splenic vein and 30-40% join the SMV. The portal vein then ascends behind the head of the pancreas to enter into the hepatoduodenal ligament. This segment of the SMV and portal vein is in close contact with the pancreas.

Venous drainage of the body and tail of the pancreas is more variable, but it consists of multiple small branches draining into the splenic vein that courses along the tail and body of the pancreas.

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Essentials of Human Physiology

Essentials of Human Physiology

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