Yep, muscle will conceal spine. It's also a fact that some breeds, when kept in lean condition, do show a little bit of spine. The amount shown there is not what I'd consider a concern.
This is my Tess in what I consider ideal condition, and as you can see, there's a hint of spine showing. I think it's pretty obvious that she is not starving:
This is my Tess in what I consider ideal condition, and as you can see, there's a hint of spine showing. I think it's pretty obvious that she is not starving: