hòu​nǎo

back of head

后脑 (後腦) hòu​nǎo
back of head noun
the posterior part of the human head

He hit the back of his head when he fell.

hindbrain noun
the posterior portion of the brain, typically including the cerebellum and medulla oblongata

The doctor said the impact injured the back of his head, but fortunately, it didn't affect his sense of balance.

Frequency

Movie subtitles
1.22 per million appears in 1% of films
Written text
1.39 per million

Sources

Definitions
CC-CEDICT