I find it kind of odd that a collarbone is used for a measure of thinness. Even at my largest (195 lbs @ 5'11") I could still see my collar bones and hip bones. Perhaps that's just due to my bone structure (I have a barrel chest and broad shoulders, my width from shoulder to shoulder is over 2 feet). I also have scoliosis which results in a slightly abnormal bone distribution relative to my height. My right hip bone is approx ~2 inches higher than my left.