Is something wrong with my frog's back?

[Sanimal]

My American green tree frog has a little bump on his back. I believe it's just the backbone slightly visible, because he has two of these little bumps; they are next to each other. However, it looks like one is just a tad larger than the other. Also, I'm sure the frog isn't malnourished because it's not skinny, has a good appetite, and looks healthy. I posted a picture of the frog (the bump on the left is the one that looks larger). Is there anything wrong? Or is it, like I said, just the backbone? Is it normal for frogs to show these two little bumps on their backs?

Thank You!

Sanimal