Outside: disease 疒 (An ice-冫-cold building 广 makes sick), inside: apex, inverted 颠 (It is truely 真 that the forehead 页 is the apex, where you return/inverte)
Mnemonic
The disease, where you "inverte" are the convulsions of a crazy person.
Picture of an eye 目 with emphasized eye-brows 首 to express the special: the head or the chief. (When used as a radical often without eye-brows 頁 meaning forehead). It is always at the right side of a character.
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