Neural tube defects: clinical correlations.

There are several approaches that can be applied to the analysis of malformations of the CNS. One practical way in making clinical correlations is to divide neural tube defects into those that arise during the period of neurulation and those that arise thereafter. This concept applies to cranial and spinal lesions and makes it possible to interpret clinical findings with embryological events. Malformations of the CNS that arise during the period of neurulation are not covered by skin and can be diagnosed prenatally by amniocentesis. Postneurulation CNS malformations are skin-covered and have differing patterns of associated malformation and etiologies. There is an overlap of the latter group with congenital tumors, and for the most part these malformations are not apt to be diagnosed prenatally.