Morphometric characterization of the human portal and hepatic venous trees: A quantitative support to the liver micro-anatomic models free of subunits

Abstract

Conventional models of liver microanatomy assume the presence of subunits. Nevertheless, some researchers propose that the liver is a continuous structure, free of these subunits, but with a characteristic vascular pattern. The present study describes a morphometric analysis of portal and hepatic veins in 50 human autopsy non-pathological liver samples. The main objective was to measure three proportions: 1. portal tracts / hepatic veins, 2. distributing portal veins / distributing hepatic veins and 3. terminal portal veins / terminal hepatic veins. These ratios were compared with the traditional microcirculatory liver models. Our material comprised 3,665 portal veins and 3,761 hepatic veins. The minimum diameter of half of the venous vessels of both types belongs to the interval (25 μm , 60 μm), given that 1881 portal veins (49.434%) and 1924 hepatic veins (50.565%) fall within this interval. We have statistically shown with the χ2 test (α=0.990) that the portal and hepatic veins belonging to the interval (25 μm, 400 μm) (distributing veins) had an identical proportion. If the portal and hepatic veins are arranged according to the principle of interdigitation of Takashasi (1970), there should be an almost identical number of both types of veins. Our results contradict the presumably numeric preponderance of distributing portal veins with regard to the distributing hepatic veins that is inherent in the models of Kiernan, Matsumoto and Rappaport.