Detecting Inner Line of a Mesh?

I was wondering if you could somehow outline both the outline of a mesh AND the “inner lines” of it.

Using the UE4 Mannequin as an example of what I’m trying to do:

I was wondering if there is a way to outline the pecs area, the divisions (like the one on the torso and on the arms), basically the “inner lines” of it, as I’m trying to achieve a specific look.

Basically the image above, but with the inner lines outlined too, is that possible?