We talk of someone having or needing to get a backbone. This of course means to get a spine. But we don’t just use “backbone” metaphorically; the word “backbone” has meant a literal spine ever since the early 1300s.
“Spine” is from the Latin spina. So a plain Saxon English / Anglish alternative for spine is backbone.
It then struck me that the backbone itself is actually made of lots of little bones: vertebrae. Each of these is surely a backbone, too. So we have backbones made of backbones? Or perhaps, made of backbonelings… I wasn’t happy with this wordmess. And then I remembered that knuckle doesn’t just mean the finger joint, it also refers to any (particularly knobbly) joint of the body. Thus, your backbone is made up of knuckles; or to be overly clear, back-knuckles. No need to use Latin spine or vertebra or that dodgy outlandish plural –ae.
© 2017 Bryan A. J. Parry
featured image from http://www.healthline.com/hlcmsresource/images/topic_centers/osteoarthritis/642×361-Treating_Spinal_Stenosis-Exercise_Surgery_and_More.jpg
Wrixlings 
That is oh so clever! I think it’s wonderful how crafty you are when it comes to making words for Anglish. Keep up the good work!
Hey, thank you for that! I try my best. 😀