Sonographic measurement of the fetal cerebellum, cisterna magna, and cavum septum pellucidum in normal fetuses in the second and third trimesters of pregnancy

Abstract

In normal fetuses, the CSP and CM should be visible on transabdominal sonography between 16 and 38 weeks' menstrual age. Because abnormalities in these cranial structures may be indicative of central nervous system malformations, the availability of mean sonographic measurements from normal fetuses should be helpful in determining the need for additional testing in fetuses with abnormal measurements.