Subsegmentation of the human liver.

Subsegmental patterns in 85 human livers have been studied after preparing corrosion casts of the hepatic duct, hepatic artery and portal vein by injecting coloured butyl butyrate solution. A subsegment was identified by the independence of its vessels and ducts from those of its neighbours. In the present study nine hepatic subsegments have been observed: (1) posterior superior, (2) posterior inferior, (3) anterior superior, (4) anterior inferior, (5) medial superior, (6) medial inferior, (7) lateral superior, (8) lateral inferior, (9) caudate (the caudate lobe and process form a spearate subsegment on the basis of the pattern of their blood supply and biliary drainage). The sizes of the subsegments were very similar in 41 cases (48.23%). In the others, some increase or decrease in the size of one or more subsegments at the expense of neighbouring subsegments was observed. These variations are illustrated.