English to Dutch Other Medical: Health Care calculations

This is from a document from America concerning all kinds of calculators for healthy living, and the body such as the BMI, the Body Fat Estimator etc. etc. It also refers to the "frame size calculator" where you enter your length, the circumference of your wrist etc. and you turn out to have either a small, medium or large frame size. I am quite sure it has to do with your bones (I am not overweight, I just have big bones! kinda thing), but cannot find a definitive expression in Dutch for frame size: skeletmaat springs to mind but does not get many Google hits. Anyone?