Configurational anatomy of the pancreas: its surgical relevance from ontogenetic and comparative-anatomical viewpoints.

Abstract

The structure of the adult human pancreas retains develop-mental traits in ontogenesis and comparative anatomy, under-standing of which greatly contributes to pancreatic surgical anatomy. The pyramidal process called the "auricle" or "ear"at the inferior margin of the neck suggests the vestige of the ontogenetic twist at the neck, resulting from bursal bulging with rotation of the pancreatic body and tail. This anatomical consideration serves to avoid inadvertent bleeding or pancreatic fistula during dissection of the right gastroepiploic arteryand vein at their roots. Recognition of embryonic rotation of the gastrointestinal tract eases detachment of the pancreati-coduodenal and jejunal vessels at their origins, enabling "reversed Kocherization" and complete resection of the mesoduodenum and upper mesojejunum. Embryological knowledge of vascular arcades of the pancreatic head serves as a guide for limited resection of the pancreas. The anterior inferior pancreaticoduodenal artery often runs behind, not in front of, the lower portion ("mentum" or "chin") of the pancreatic head, but still on the anterior leaflet of the embryonic mesoduodenum. The attachment of the adult pancreatic head to the duodenum occurs only at the major papilla of Vater and at the region around the minor papilla, which seems to be rational from ontogenetical and comparative-anatomical aspects. Knowledge of the pancreatic attachment helps when performing duodenum-preserving pancreatectomy and pancreas-sparing duodenectomy. The "lingula" or "small tongue", a pancreatic portion overlapping the common bile duct on the posterior aspect of the pancreas, is a key structure in resection of the extrahepatic bile duct.