We have a handy hand mnemonic for this purpose 1. Also, remember that the segments are numbered in a clock-wise fashion.
With the right hand, make a fist while tucking the thumb behind the remainder of the fingers.
Tucked in thumb = Segment I (Caudate Lobe)
Line of Proximal Interphalangeal (PIP) joints = Plane of portal vein, separating liver into upper and lower segments.
Interdigitary spaces = Intersegmental planes (hepatic fissures – left, middle and right) in which corresponding hepatic veins run and divide liver sagitally
For the remaining 7 segmets, go in a clockwise direction starting from the lateralmost upper left part, i.e. Proximal phalax of 1st finger.
Proximal phalanx of 1st finger = Left superior lateral segment = Segment II
Distal phalanx of 1st finger = Left inferior lateral segment = Segment III
2nd finger = Left medial segment = Segment IV (Quadrate lobe)
Proximal phalanx = Segment IVa
Distal phalanx = Segment IVb
Distal phalanx of 3rd finger = Right inferior anterior segment = Segment V
Distal phalanx of 4th finger = Right inferior posterior segment = Segment VI
Proximal phalanx of 4th finger = Right superior posterior segment = Segment VII
Proximal phalanx of 3rd finger = Right superior anterior segment = Segment VIII
Information credits https://epomedicine.com/medical-students/liver-segments-explained-mnemonic/