The pancreas is a tongue-shaped retroperitoneal organ (Figure 37.1). It is located within the anterior pararenal space, along with the ascending and descending colon, as well as the duodenum. The pancreas is divided into the uncinate process, head, neck, body, and tail. The long axis of the gland most commonly follows an oblique course, with the head at the eight o’clock position and the tail at two o’clock. The normal dimensions of the pancreas depend on many factors, the most important of which is age. It is normally 12–15 cm in length. The head should measure up to 3.0–3.5 cm, the body up to 2.5 cm, and the tail up to 2.0 cm. These sizes are variable, and there is a great deal of variation. Generally, the gland tapers in size from head to tail. Fatty infiltration of the gland lobules is common with age. This gives the gland a more lace-like or feathery appearance. The pancreatic duct runs through the entire length of the gland and may measure up to 3.0 mm in the head and body and gradually tapers in the tail. It is often partially visualized, more commonly on thin-section computed tomography (CT). The common bile duct (CBD) passes through the pancreatic head before it joins the pancreatic duct near the ampulla of Vater. The size of the CBD in the pancreatic head varies with age as well but should never exceed 10 mm, often attaining the larger diameters in patients postcholecystectomy.