The posterior fossa is small with evidence of tonsillar herniation through the crowded foramen magnum. Mild cervico-medullary kinking. Downward displacement of cerebellar vermis is also noted. Pulled down brainstem.
A small/collapsed fourth ventricle is noted. Dilated both occipital horns (colpocephaly). No evidence of hydrocephalus.
No obvious tectal beaking. Hypoplastic/ underdeveloped tentorium with abnormally low insertion at the occipital bone and low torcula.
The cerebellar hemispheres are wrapped around the brainstem.
Abnormal course straight sinus is noted.
Mild flattening of the pons with effacement of the prepontine cistern.
Severe thinning of the corpus callosum with possible absence/dysgenesis of its distal body and splenium. Septum pellucidum is present.
No evidence of encephalocele.
Thoracolumbar meningocele is noted through bony defect without evidence of neural or fatty elements.
Normal level of conus medullaris, no evidence of tethered cord.