in_left_side_of
BSPO:0000120
X in_left_side_of Y <=> if Y is subdivided into left and right portions, X is part_of the left portion.
https://github.com/obophenotype/uberon/wiki/Modeling-paired-structures-Design-Pattern
in_left_side_of
in_left_side_of
uberon
in_lateral_side_of