Hepatic segmental anatomy

Abdomen

The liver is morphologically divided into a right lobe, left lobe, and caudate lobe. The right and left lobes can be divided into subsegments based on vascular supply and biliary drainage that permit partial hepatic resection for tumor.

Hepatic anatomy in the axial plane. The right and left lobes are separated by the middle hepatic vein. The left lobe is further subdivided into subsegments 2, 3, 4a, and 4b. The right lobe is subdivided into subsegments 5, 6, 7, and 8. The caudate lobe is segment 1.

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Hepatic anatomy in the coronal plane.

Subsegmental anatomy can be remembered using the hand as a model. The thumb corresponds to segment 1. Subsegments 2–8 form a clockwise loop around the digits, with 4a and b located on the middle finger.