ABSTRACT
Various areas of the fetal skeletal system may be affected in several syndromes. For this reason, proper diagnosis of limb, thoracic, and skeletal dysplasias can be key in reaching the proper diagnosis. The value of volume sonography in studying the fetal spine has been primarily evaluated with respect to development of the spine and localization of neural tube defects. Skeletal dysplasias cover a wide spectrum of syndromes, with subtle differences involving various areas, and varying degrees of bone ossification. The iliac angle is reportedly wider in fetuses with trisomy 21, but is difficult to measure. Two areas where Three-dimensional ultrasound has been shown to be of clinical utility with respect to the fetal skeleton are counting the ribs and determining the level of involvement in the case of a neural tube defect, otherwise not possible with routine Two-dimensional sonography.
