The phrase<unk>  insinuates that as long as violence does not leave a mark, it is not prosecutable. It has been used in streetball, Camp Nama, torture, and medical malpractice.
No blood, no foul
Serous fluid
Ubi pus, ibi evacua
Eggs per gram
Hematoxylin body
Speculum 
Bloody show
Von Braun-Fernwald's sign