An anastomosis between the common trunk of the middle and left hepatic veins of the receiver and the cranial portion of the inferior vena cava of the donor is one of the techniques for restoration of hepato-caval continuity in orthotopic liver transplantation. This technique avoids dissection of the retrohepatic vena cava and total caval clamping. The aim of this study was to define the feasibility of this technique by a morphologic and biometric study of the common trunk of the middle and left hepatic veins on the basis of 64 injection-corrosion hepatic specimens and 21 fresh subjects. A common trunk for the middle and left hepatic veins was present in 54 of 64 cases (84%) with a length of 3 to 17 mm. The diameter of the new ostium constructed by section 0.5 cm proximal to the junction of the middle and left hepatic veins was 23.9 +/- 2.3 mm, which approximated to that of the vena cava where it traversed the diaphragm (24.4 +/- 2.0 mm). These findings confirmed that restoration of hepato-caval continuity by anastomosis between the common trunk of the middle and left hepatic veins of the receiver and the cranial portion of the vena cava of the graft is possible without incongruence. This study makes no assumptions about the hemodynamic effects associated with the smallest diameter of the true ostium of the common trunk at its opening into the inferior vena cava. In this study, the morphology of the common trunk was comparable to that observed by Nakamura. Further, we propose an anatomo-clinical classification allowing evaluation of the facility of vascular control of the common trunk in terms of the number and location of the collateral veins.