system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is a sternum rub so painful? Paramedics and hospital workers rub the sternum to see if the patient is conscious. It's the most common painful stimuli thats administered but what about the sternum makes it so painful when you rub it.

I've always wondered this. Its the most common painful stimuli technique used. But what about the sternum makes it so painful when you rub it? Slapping the face is always used in the movies (I know movie stuff isnt real) and I feel like slapping someone in the or pinching them is a good way to get them to respond.
gpt
A sternum rub is better than slapping someone because that could be really bad if they had a broken neck, a jaw fracture, a brain injury, etc. Pinching in the extremities may not work if that extremity has nerve damage or is otherwise numb.

The sternum rub is painful because it crushes tissue against the bone of the sternum, and because it is central to the body it minimizes the possibility of nerve breaks from injury along the way. If you can't feel your sternum then you probably can't breathe either, so... you probably aren't responding because you are dead.