Isn't "behind your back" in front of you?

We've all heard the phrase that usually goes along the lines of "blah blah did something behind my back". I've always thought that from your back's point of view, anything behind you is in front of it therefore behind your back is in front of you. Is this just another unnecessary redundancy and should we all just say "behind me" or am I reading too much into this?

Solution 1:

I think behind your back is redundant, but not nonsensical. Something that's behind your back is behind you -- not just behind your toes or your nose, but even further to the rear -- behind your furthest back part.

Solution 2:

I've always thought that from your back's point of view, anything behind you is in front of it therefore behind your back is in front of you

If that was true then it would be impossible to be behind anything. For example if one said that something is "behind my house", of course it is actually in front of one of the surfaces of my house so it could not be "behind my house".

It's much the same as doing something "in front of my eyes" rather than "in front of me". I think this is called "the power of idiom" or something like that; once a phrase becomes an idiom it doesn't have to make sense any more.

Solution 3:

The phrase "went behind my back" is to emphasize hidden and sneaky behavior. You can not say "in front of my back" because that seems like you could face your own back, but you cannot. Your back in this sense is a noun. Think backache.

This phrase is more of a saying than literally meaning physically behind you. It means that you were not consulted, but excluded from a decision.