One-punch deaths fall even further down the list. But it happens often enough that Gunson, without pause, is able to describe precisely how a sock to the face can end a life.

"They fall over backwards and they hit the back of their head," Gunson said. "They often end up having a skull fracture."

The impact on hard ground causes the brain to ricochet into the opposite wall of the skull -- somewhere around the forehead -- causing hemorrhaging near the brain and death. It's known as a contrecoup brain injury.

Also

Or, in cases when the victim has been drinking heavily, a punch to the face can cause an artery at the base of the brain to fatally tear as the head snaps back.

These are about people being knocked unconscious by a punch and then what kills them is hitting the solid pavement. Not the same as someone generating enough force to break someones skull with a punch.