Readout - What to think about when the femur seems too short
Take Home Points
FILLY'S RULE FOR DIAGNOSING SKELETAL DYSPLASIAS
Never diagnose a skeletal dysplasia if the bones visually look normal to you!
HOW TO APPROACH THE "SHORT" FEMUR
As we noted in this video, pay close attention to the fetus' age by clinical dates. In this instance the femur is only 1 week, 1 day behind clinical dates. This is not a particularly significant difference. It is only when you compare to the head size that the difference seems huge. So, is the head too big? In this case, we can conclude that the intracranial contents are normal (No hydrocephalus, No mass), so we would interpret this as simple genetic variability among families. (ie A short person with a big head) because morphologically the head and femur both look normal.