If you go to the emergency room in the United States, what brought you there is most likely a sprain or strain, a stomachache, or a cold-type-thing that seems unusually severe.
Either that, or it's an injury that may or may not be a broken bone but wow-wee does it hurt. And it's getting swollen. Better go in just in case.
Then, after an average 28-minute wait, the ER doctor will tell you that it's just a contusion, another word for a really bad bruise. Then he'll charge you three times more than your family doctor—or thousands of dollars, if you're uninsured. In the Northeast, this was the most common thing that happened in emergency rooms in 2011.
But each state has its unique boo-boos. As you can see from the map above, which I created from new data provided by the Agency for Healthcare Research and Quality, in the South, the most common complaint was a sprain or strain; for the West, it was abdominal pain; and for the Midwest, it was respiratory infections. (Not all states send their ER data to the AHRQ, so the agency lumps them together by region instead.)
For the most part, though, the regional variation means nothing—each region has the same top four complains, just in a different order. And in some cases only a few thousand patients separate the most common complaint and the second-most common one.