IPA: /ˌpoʊstərəˈleɪtərəl/
KK: /ˌpoʊstərəˈleɪtərəl/
Located at the back and to the side of something.
The surgeon made an incision in the posterolateral region of the knee.
Posterolateral → It is formed from "postero-" (from Latin "posterus", meaning behind) and "lateral" (from Latin "lateralis", meaning side). The word describes a position that is located behind and to the side.
Think of something that is 'behind' ('postero-') and 'to the side' ('lateral') — that's what posterolateral means.