The head of the pancreas is the biggest part of the pancreas. The common bile duct enters this area of the pancreas. The head is attached to the main part of the pancreas, the body. The head is tucked into the bend of the duodenum. The duodenum's superior part overlaps the top border of the head and the horizontal part overlaps the lower border. There is an overlap in front by the left and right borders. They are respectively placed behind the ascending and descending portions of the duodenum. The uncinate process is the prolongation at the angle of junction of the lower and left lateral borders. Between the right lateral and lower borders in front, and the duodenum there is a groove where the superior and inferior pancreaticoduodenal arteries anastomose. Near the right border the common bile duct falls behind and ends in the portion of the duodenum that descends.