Inferior pancreaticoduodenal artery

Origin and course

The IPD artery stems mainly from the right or posterior aspects of the superior mesenteric artery (SMA). The point of origin is close to the superior limit of the horizontal part of duodenum and the inferior border of the neck of pancreas. Sometimes, the IPD artery arises from the first jejunal artery, which is a branch of the SMA that supplies the ascending part of duodenum. 

As soon as the IPD artery exits from its origin, it divides into anterior and posterior branches. They ascend towards the uncinate process of the pancreas, traveling to the right and posterior to the superior mesenteric vessels. Both branches continue to ascend along with the head of the pancreas. The anterior branch travels anteriorly while the posterior branch courses posteriorly to the head.

Superiorly, the anterior and posterior branches of the artery together with the anterior and posterior superior pancreaticoduodenal arteries, form a network of arteries that supply the pancreas (head and uncinate process) as well as the duodenum.

Branches and supply

The inferior pancreaticoduodenal artery has two main branches:

• Anterior inferior pancreaticoduodenal artery which supplies the anterior aspects of various parts of the pancreas (head, uncinate process) and duodenum (descending and horizontal parts). This branch anastomoses with the anterior superior pancreaticoduodenal artery, anterior to the head of pancreas, to form the anterior pancreaticoduodenal arcade.
• Posterior inferior pancreaticoduodenal artery vascularizes the posterior aspects of the same anatomical structures supplied by its anterior counterpart. This branch anastomoses with the posterior superior pancreaticoduodenal artery, posterior to the head of the pancreas, to complete the posterior pancreaticoduodenal arcade.

Learn more about the arteries around the pancreas using the articles, videos, quizzes and illustrations in the following study unit.
 

Anatomical variations

The IPD artery can be quite varied in terms of origin. According to classical anatomical textbooks, the artery stems from the SMA or from the first jejunal artery. Less commonly, the inferior pancreaticoduodenal artery can arise from other sources; right accessory hepatic artery, a common trunk with the dorsal pancreatic artery, second or third jejunal arteries.

The origin also impacts the course of the first portion of the IPD artery. When arising from the left side of the SMA, the IPD artery runs shortly to the left then it turns to the right and crosses posteriorly. If the origin is higher, from the retropancreatic portion of the SMA, it travels downwards to reach the posterior aspect of the uncinate process and then divides into anterior and posterior branches. 

Significant variations are present even in the branches of the IPD artery. In up to 30-40% of cases, either the anterior or posterior branch can stem from the first jejunal artery. In addition, the IPD artery can give off some inconstant collaterals in certain individuals.