Preface: Beware that Spanish (eg: los planos coronales) and Portuguese also derive from the Latin corona; so this question transcends English etymology.
https://en.wikipedia.org/wiki/Coronal_plane#Etymology
The term is derived from Latin corona (“garland, crown”), from Ancient Greek κορώνη (korōnē, “garland, wreath”).
How does the crown relate to the front? Please expose and explain the hidden, missing semantic drifts and links. How should the etymology be interpreted, to connect the ulterior acceptation with the original meaning?