Basis of division of anatomical segments of liver are all, EXCEPT:

The proper hepatic aery, poal vein, and common hepatic duct enter/exit the liver at the poa hepatis as the 'poal triad'. The central branch first divides into two larger branches, functionally subdividing the liver into left pas and right pas. The poal triad continue to ramify within the liver, forming a total of eight segments that are more or less functionally independent of one another. Hepatic segments grouped by pas and divisions: Left pa of the liver 1. Posterior pa, Caudate lobe Segment (S1) 2. Left lateral division 1. Left posterolateral segment (S2) 2. Left anterolateral segment (S3) 3. Left medial division Left medial segment (S4); subdivided into subsegment (4a) and (4b) Right pa of the liver 1. Right medial division 1. Right anteromedial segment (S5) 2. Right posteromedial segment (S8) 2. Right lateral division 1. Right anterolateral segment (S6) 2. Right posterolateral segment (S7)