Short legged syndrome. A condition where the legs are disproportionately short compared to the torso. This is not dwarfism, but rather a physical trait confined to the legs. SLS is a cause of women not becoming models and men being insecure. Cases of SLS are prominant in certain geographical areas and rare in others.
It's a good thing your girlfriend wore her 4" heels. Otherwise her SLS would have stood out.