The short answer is yes. You've seen it yourself if you think about it. Ever notice an adult with extremely 'fine boned ' hands, wrists, and feet? Then people with a wrist it would take both your hands to wrap around and a fist the size of your skull? There is no real fat or musculature in those areas, thus that IS a difference in skeletal size and density. Now that term is usually just mis-used to describe someone overweight.