Chronic duodenal dilatation is a frequent pathologic condition. This assertion is based, not alone on clinical observations, but also on the well known anatomic faults of the adult human duodenum. Normally the human duodenum has practically no mesentery; it is fixed dorsally by an abundant retroperitoneum, is indented in front and behind by blood vessels and is impinged on by contiguous structures. The quadruped has a long mesentery and freely movable duodenum. Comparative study shows that the human is paying the price of a potentially pathologic condition for the upright posture.
Embryologically, the human duodenum has a long mesentery and consequently free movement. Should the adult retain this condition the major etiologic factors of pathologic conditions of the duodenum would be removed.
The duodenum of the thirty to sixty day embryo is occluded by a vacuolated epithelial plug. Synchronous with the solid state of the gallbladder and cystic ducts, the