I think what she meant is that the woman was narrower on top - across the back. She has boobs, but the frame of her upper body is smaller. Does that make sense?
Well since she accused me of being a cello, then i'll accept being called "narrow" any way I can.

Personally I think I have the upper body of a wrestler...
I don't know how much I believe though. In the book, they accuse Kim Cattrall of being a brick! Now I was watching Sex and the City last night before I'd seen that, and I thought to myself, she must be hourglass as she has the tiniest waist.....and I was seeing her in all her glory as well... who knows?