entries → 傷腦筋
TSUMUGU · TOCFL B2 (est.) · 詞
傷腦筋 word · TOCFL B2 (est.)
傷腦筋 ＝ 傷 ＋ 腦 ＋ 筋
ㄕㄤ ㄋㄠˇ ㄐㄧㄣ · shāng nǎojīn
verb phrase / adjective — to be a headache; to rack one's brains; troublesome, vexing

字源 FORM — what the parts do

傷to hurt, wear out (受傷)shāng
腦the brain (大腦)nǎo
筋tendon, sinew (筋骨)jīn腦筋 = the brain's wiring, one's wits
傷腦筋，受傷的傷，大腦的腦，筋骨的筋。

故事 STORY — a scene to remember it by

問題太難，想到腦筋（腦筋）都用傷（傷）了。
A problem so hard it wears the brain's wiring (腦筋) sore (傷).
記憶法
關 · Related
腦筋nǎojīnone's wits, mind — the thing 傷腦筋 wears out頭痛tóutònga headache — the same metaphor for a vexing problem