Chiari 2 malformation

Findings

There is enlargement of the lateral ventricles and third ventricle. The fetal Posterior fossa appears small with downward displacement of the cerebellar tonsils. There is discontinuity of the posterior elements beginning at the thoracolumbar junction with myelomeningocele at this level.


Diagnosis: Chiari 2 malformation


Key points

Complex deformity of the calvarium, dura, and hindbrain
Almost always associated with a myelomeningocele
Lacunar skull
Concave clivus and petrous ridge
Small posterior fossa
Fenestrated falx
Cerebellar peg
Medullary kink
Towering cerebellum
The cerebellopontine cistern and the cisterna magna are obliterated
Beaked tectum
Hydrocephalus
Prominent mass intermedia