ABSTRACT
Shortened femur length is the commonest presentation for suspected skeletal problems, as this is the only bone that is routinely measured in obstetric ultrasound. In the majority of cases, shortening of the long bones is likely to represent inaccurate dating, constitutional smallness, or an early feature of fetal growth restriction. The latter must be excluded before contemplating a diagnosis of a fetal skeletal dysplasia, a heterogeneous group of disorders characterized by abnormalities of cartilage and bone growth. Typically, a diagnosis of a fetal skeletal dysplasia before 24 weeks results in a poor outcome due to thoracic dysplasia.
