Green’s Dictionary of Slang

bone box n.

1. [late 18C–mid-19C] the mouth.

2. [late 19C–1940s] (US) a coffin.

3. [1940s] the head.

4. [1970s] (US) an ambulance.

5. [1970s+] (US prison) a hearse.

In phrases

button one’s bonebox (v.)

[mid-19C] (US) to be quiet.