Don't the Klingon spines have protrusion all the way down the back? I seem to remember that from an episode when Worf injured his back. The 'spine' thing at the back of the battle armor is to protect what's on the outside of the spine on the body?
http://memory-alpha.org/wiki/Ethics_(episode)
under Background Information.
Comments
Here's how the spine armor looks now (screenshot taken today)
Here's how it looked at launch of STO (screenshot taken January)
And Here's how it looks in the canon (Christopher Loyd in costume)
And while I'm on a klingon costuming tirade:
Can we get the lettering on the gauntlets. This is what it looks like and it's that way on pretty much every canon Klingon we see on screen (I think).
My rant is more related to the armoring on the actual naked spine, not the uniform spines. There is supposed to be armoring on the spine itself, when wearing a uniform like the UFP Mirror Uniforms.
I'm pretty sure it was shown in Ethics at least, when Worf was on the operating table. The spine anyway.