The upper class is those that ridiculously big amounts of money, yes. Some definitions would put high-ewrning lawyers and doctors up their, but today it doesn't make sense to put them all together given the extreme wage gaps in the US.
The divide is that wide, so of we're using the typical 'upper middle lower' stratification of class, then yes; all those incomes fall within it. Keep in mind that the US has, by far, the biggest divide in earnings out of any developed country; the rich are richer, the poor are poorer than almost anywhere else. Middle class by that definition has to be big, if we're basig it solely on economic class, but even then it's still relatively subjective. 
I think a general definition that would work everywhere is that if you *own* property, an apartment or a house, you're middle class, definitely if you've bought a house.   
Another thing to remember is just because you're making more money than someone doesn't make them poor, it makes you better off.  
The us seems like a completely different ball game to the rest of the world even if it's only because there's a much bigger emphasis on money than never anywhere else.