How to understand if motherboard still works. HELP

Hello everyone,

Nexus 4 screen and back cover are completely cracked. In addition the front screen and the grey plastic support were slightly bent.

I disassembled the phone and..to my incompetent eyes the motherboard looks intact.. the only damage is to the black plastic midframe.

I would like to replace the screens but before making the purchase I would like to know if there is any way to understand if the motherboard actually works.

Thank you very much

Matilde