Visualization of the fetal spine: a proposal of a standard system to increase reliability.

We describe a method for the morphological, developmental, and functional analysis of the fetal spine. Using this system, different types of spina bifida and hemivertebrae have been discovered. A system of quality control and documentation is proposed and cases that were not detected ultrasonographically are described. The results of the analyses of seven abnormal fetuses out of 818 pregnancies examined by us and three referred after birth are presented, including fetuses with caudal regression, spina bifida, hemivertebrae with lordosis and kyphosis, and spina bifida without ultrasonographic or radiologic evidence of bone abnormality. Cases that were not diagnosed ultrasonographically by other observers are presented.