Anatomic and sonographic features of the fetal skull.

This article reviews developmental skull anatomy, especially as it relates to the formation of cranial sutures and fontanelles, and demonstrates the appearance of these structures on prenatal sonograms, illustrating the framework these structures provide to enable one to accurately identify components of the fetal skull. Examples are provided to illustrate the utility of this knowledge. An understanding of fetal skull development and appearance enables the sonographer to better characterize fetal cranial abnormalities. More importantly, recognition of the location of cranial sutures and fontanelles and their ability to serve as acoustic windows assists the sonographer in evaluation of the fetal brain.