Portasystemic collaterals develop as a result of portal hypertension. The collaterals in the cardioesophageal region is the leading cause of bleeding from esophageal varices. Some of the portal hypertensive patients present with bleeding episodes but the others do not, and some of the bleeders do not respond to endoscopic sclerotherapy procedure, although the underlying pathology is the same. The capacity of the natural collateral vessels might be a determining factor about the hemorrhagic events. Since the first step of portasystemic collateralization takes place in the naturally existent vascular channels, the present study, with its anatomic and clinical parts, was focused on these venous structures. (C) 2003 Elsevier Inc. All rights reserved.