Normal venous circulation of the gastroesophageal junction. A route to understanding varices.

A study into the normal anatomy of the venous circulation of the gastroesophageal junction was undertaken using three complementary techniques (radiology, corrosion casting, and morphometry). Four distinct zones of venous drainage were defined as follows: (a) gastric zone, characterized by a longitudinal venous distribution; (b) palisade zone, composed of parallel vessels arranged in groups, lying mainly within the lamina propria; (c) perforating zone, characterized by "treble clef" shaped veins, which collect and channel blood into extrinsic veins; and (d) truncal zone, composed of four or five deep lying descending veins. This venous system appeared to be mainly distributed within the esophageal mucosal folds. The anatomic pattern suggests that venous flow is bidirectional at the palisade zone, which acts as a high-resistance watershed region between the portal and azygos systems. In patients with portal hypertension this normal vascular system has to accommodate greatly increased venous flow, and the anatomy as demonstrated here offers insight into variceal development.