spoon hips 

description of a woman's lower abdomen in which her waist hangs concave below her hip bones and pubic mound (vulva) creating the impression that her lower abdomen is concave like a spoon. The effect is heightened if her hip bones are set wide apart and she has a narrow upper body - like the handle of the spoon.

That model is so thin she has spoon hips.

spoon hips by wouldaben January 4, 2011