Real-time ultrasonography of the posterior fossa.

The authors ultrasonographically identified abnormalities of the posterior fossa associated with meningomyelocele (Arnold-Chiari type II malformation), Dandy-Walker malformation, extracerebellar hemorrhage, and post-hemorrhagic enlargement of the fourth ventricle. Normal anatomic and pathologic features of the posterior fossa are illustrated, and the use of realtime ultrasonographic sector scanning in the posterior fossa is discussed.