Anatomy - Pancreatogastrostomy - general and visceral surgery

The pancreas is made of lobules and has a reddish-grey color, is 14 - 18 cm long and weighs 65 - 80 grams. It is located at the level of the first and second  lumbar vertebrae and extends in a wedge shape from the epigastric region to the left hypochondriac region. Embryologically, the organ is situated in close relation with the upper abdominal organs and vessels.

The pancreas is invested by capsule-like connective and fatty tissue and is divided into three sections: Head, body, and tail. Whereas there is a somewhat firmer connective tissue lamina along the posterior aspect of the head, the gland is otherwise mainly loosely bound by connective tissue in the posterior region. As a retroperitoneal organ, the gland is overlaid by peritoneum on its anterior aspect.

The gland is widest at the head, which nestles within the curve of the duodenum just to the right of the spine. Both the anterior and posterior aspects of the duodenum may be overlaid to varying degrees by glandular tissue. The head, with its caudal portion (uncinate process), cradles the superior mesenteric vein from posteriorly and occasionally the artery as well. The notch in the uncinate process extending along the junction of the left half of the pancreatic head and the neck of the pancreas is known as incisura pancreatis.

With a width of approx. 2 cm, the region of the pancreas at the level of the first lumbar vertebra constitutes the transition zone between the head and body of the organ and is located craniad to the superior mesenteric vessels. From a surgical perspective, this is also known as the neck of the pancreas.

The elongated pancreatic body extends diagonally and upwards anterior to the first and second lumbar vertebra, protruding anteriorly into the lesser sac and arcing toward the splenic hilum; it transitions to the head without an exact anatomical delineation. The aorta, inferior vena cava, and superior mesenteric artery and vein are located posterior to the pancreas and adjacent to the spine.

The pancreatic tail constitutes the tapered continuation of the body and extends to or even into the splenorenal ligament.

The pancreatic anlage may take various shapes – oblique, S-shaped, transverse, and L-shaped. Horseshoe and inverted V-variants have also been described. The transition between these variant shapes is fluid.

Pancreatic topography comprises the following relations with neighboring organs and retroperitoneal pathways:

• Anteriad, the lesser sac and posterior aspect of the stomach
• To the right, a close relation between the head of the pancreas and the curve of the duodenum
• To the left, a close relation with the splenic hilum
• At the level of the head, the posterior aspect of the pancreas touches the portal vein, superior mesenteric artery and vein, and common bile duct, while at the level of the body it touches the splenic artery and vein, inferior mesenteric vein, inferior vena cava, and abdominal aorta; at the level of the tail the posterior aspect touches the left kidney.

The pancreatic duct is approximately 2 mm wide and traverses the organ in its long axis close to the posterior aspect. Along its path, numerous short glandular ducts terminate in the pancreatic duct at right angles. In about 77% of cases, the duct together with the common bile duct drains into the major duodenal papilla at the posterior wall of the descending duodenum; in the remaining cases, both ducts terminate separately but close together. Quite often the accessory pancreatic duct, ductus pancreaticus accessorius, is only rudimentary or completely absent. If present, it empties into the minor duodenal papilla.