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back of head
転んで後頭部を強く打ってしまった。
I fell and hit the back of my head hard.
後頭部にしこりができて不安だ。
I am worried because a lump formed on the back of my head.
ボールが後頭部に当たって病院に運ばれた。
A ball hit the back of his head and he was taken to the hospital.