Several times throughout my childhood, i've hit my head on various hard objects, like tables, metal bed frames, and fell flat on my face on a hardwood floor and broke a few baby teeth, and then on security bars on a window much later on in my late 'teens, but no sustained/permanent head injuries from any of these accidents
I've also slipped and fallen down stairs a several times with no major injuries, but i do have a small scar on my shoulder from my cat who tore into my skin while racing around the room ¯\_(ツ)_/¯