A 79 year-old European female cadaver presented the usual features of second stage arrested mid-gut rotation accompanied by unusual mesenteric attachments and pancreatico-duodenal relationships.
The mesentery, whose root extended from the lower pole of the right kidney diagonally across the posterior abdominal wall to end just medial to the left sacroiliac joint, enclosed most of the small bowel and the proximal large bowel. The unusually short duodenum began 2.5 cm to the left of the mid-line and described a 13 cm U loop with an upward concavity in which rested the pancreas; this loop and the related pancreas were enclosed in a persistent, transversely placed mesoduodenum. The common bile duct crossed the anterior surface of the pancreas to open at the greater duodenal papilla 2.5 cm from the pylorus. the main pancreatic duct lay much closer to the anterior than to the posterior aspect of the gland. The lesser duodenal papilla was situated on the posterior wall of the duodenum. The hepatic artery arose in common with the superior mesenteric artery and encircled the pancreas. The pancreatico-duodenal vessels were predominantly distributed upon the posterior aspect of the pancreas and duodenum.
It appears that in this specimen the anterior and posterior aspects of the duodenum are transposed, the reversal of surfaces also involving the pancreas. Causative factors are discussed with reference to the literature.