Calculate thickness of thin muscle

Hi, I am still trying to figuring out what my result of your workflow (How to analyze the thickness of the model) means… What does the colours mean and how do I get the exact medial surface (that I assume is the thin green line in your example) ?

I am also trying to compute a skeleton labelmap, but I can’t find it in “Representations” under Segmentations-module, even if I have installed SlicerRT to get additional representations. How can I add this skeleton labelmap?

Thanks!