Quick (and maybe dumb) question on chirality

[Attraction]

Homework Statement

How are my hands not constitutional isomers?

The Attempt at a Solution

I read this in a book today (Organic Chemistry for Dummies - good book actually), and I was covering chirality. Now, I am a bit shaky on it and need to go over it, but I got stuck on this for a while. The author stated that your hands are stereoisomers rather than consitiutional isomers.

Here is my thought process...

A constitutional isomer has the same molecular formula but some of the atoms are not in the same location. A stereoisomer is a molecule with the same molecular formula but a different 3D orientation.

Now, for my point. My hands have the same molecular formula (4 fingers and one thumb). The thumb and pinky are not structurally in the same place from hand to hand. Isn't that what a constitutional isomer is? I mean, my hand still has the same molecular formula but just a different structure. It's like comparing butane to methylpropane, different structure but still an isomer.

So what am I missing?

 

[Borek]

Mirror image.

Actually, if you will list your fingers starting from thumbs, you will find out that both hands are identical - even if obviously they are not.

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[chemisttree]

Switch your thumb and your middle finger. Compare this constitutional isomer with the other hand. Not mirror images yet they have the same formula (4 fingers, 1 thumb).

Compare your unaltered hands. Mirror images but not constitutional isomers. Middle finger in middle... thumb off by itself, etc. These are stereoisomers.

 

[Attraction]

Thanks guys, I got it!