8. Incise the peritoneum at the right border of the duodenum and reflect it medially. Identify the arterial supply to the pancreas and duodenum.

Pancreaticoduodenal Vessels
The main blood supply to the head of the pancreas is derived from the gastroduodenal artery. Recall that this splits into the gastroepiploic and the anterior/superior pancreaticoduodenal. The anterior/superior pancreaticoduodenal runs along the head of the pancreas and it branches to the pancreas and to the duodenum itself. The anterior/superior pancreaticoduodenal artery passes downward and curves to the left. It continues to the left to the uncinate process, behind the superior mesenteric artery and vein, shown here. The distal end of the anterior/superior pancreaticoduodenal artery may be embedded in the uncinate process. It may be necessary to dissect it out to follow it. Here the portion of the uncinate process is being elevated to follow the continuity of the artery towards the superior mesenteric artery. The anterior/inferior pancreaticoduodenal artery arises from the superior mesenteric. The head of the pancreas is also supplied by the posterior/superior pancreaticoduodenal artery. In order to visualize this artery it is necessary to reflect the second portion of the duodenum to the left. This procedure, called a Kocher maneuver utilizes the fusion fascia behind the duodenum and pancreas. This avascular plane is demonstrated here by inserting a finger behind the pancreas. Return, once again, to the first part of the duodenum. Recall that the gastroduodenal artery, which arises from the common hepatic artery, passes behind the first part of the duodenum. Just before it goes behind, it gives off a vessel which passes around the common bile duct into the posterior part of the pancreas. This is the posterior/superior pancreaticoduodenal artery. It continues along the posterior curvature of the pancreas and duodenum at the junction to form an arcade which supplies both duodenum and pancreas. Here we see the posterior/superior pancreaticoduodenal artery giving off duodenal branches to the head of the pancreas. The artery continues inferiorly as an arcade and heads towards the superior mesenteric artery. The distal end of the posterior/superior pancreaticoduodenal artery anastomoses with the posterior/inferior pancreaticoduodenal artery. The posterior/inferior pancreaticoduodenal artery arises in common with the anterior/inferior pancreaticoduodenal artery off the superior mesenteric artery as shown here. The common vessel passes to the right and splits into an anterior/inferior pancreaticoduodenal artery and posterior/inferior pancreaticoduodenal artery, which complete the arcades. The remainder of the pancreas receives its arterial supply from the splenic artery. Splenic artery runs along the superior surface of the pancreas, partially embedded in it. It passes transversely to the hilum of the spleen, supplying the pancreas in its course. Recall that is arises from the celiac trunk and then passes to the left. It is very tortuous and easily identifiable by its shape. It gives several branches to the pancreas itself. It first rises near the origin of the splenic artery and passes behind the pancreas. It is called the dorsal pancreas artery. Midway along the body there is usually a large vessel called the great pancreatic artery or pancreatica magna. It supplies most of the body, shown here. Near the tail of the pancreas, caudal pancreatic branches arise from the splenic to supply the tail. The dorsal pancreatic artery in this particular vessel is quite small. Consequently there is a large inferior branch off the superior mesenteric artery to take its place. This artery passes superiorly and then splits in the specimen. The branch to the left is the inferior pancreatic artery and runs along the duct of the pancreas. The branch to the right joins the anterior/superior pancreaticoduodenal artery and is called the pre-pancreatic arcade. It supplies the uncinate process in the portion of the head.