Background: Portal branching patterns that differ from those previously described are occasionally encountered during liver surgery.
Methods: A total of 60 patients with normal intrahepatic venous anatomy underwent helical computed tomography during arterial portography (CTAP). Next, 3 dimensional portograms were reconstructed to verify the locations of the portal veins. Portal branching patterns in the right hemiliver were assessed.
Results: In all 60 patients examined, the right anterior portal vein bifurcated into the ventral and dorsal branches. In 42 (70%) of 60 patients, some branches arose from the right posterior portal trunk. Between 1 and 3 branches (mean 2.3 branches per patient) coursed cranially, between 2 and 5 branches (mean 3.2 branches per patient) coursed caudally, and between 1 and 2 branches (mean 1.3 branches per patient) coursed laterally.
Conclusions: We propose that the right liver should be divided into 3 segments, which are designated as the right anterior, middle, and posterior segments.