Stepwise evaluation of liver sectors and liver segments by endoscopic ultrasound

Table 1 The sectors and the segments of liver

Four hepatic sectors	Eight hepatic segments
	Segment I - the caudate lobe
Left lateral sector	Segment II - posterosuperior
	Segment III - anteroinferior
Left medial sector	IVa - superior segment
	IVb - inferior segment
Right anterior sector	Segment V - inferior segment
	Segment VIII - superior segment
Right posterior sector	Segment VI - inferior segment
	Segment VII - superior segment

This table shows the relationship of hepatic sectors and hepatic segments. The four segments of left liver are: I (caudate); II (left lateral superior); III (left lateral inferior); and IV (left medial) [subdivided into superior (IVa) and inferior parts (IVb) by Bismuth]. The four segments of right liver are: V (right anteroinferior); VI (right posteroinferior); VII (right posterosuperior) and VIII (right anterosuperior). The caudate lobe is often called an independent segment.