Ascending transtentorial herniation is a situation where space-occupying lesions in the posterior cranial fossa cause superior displacement of superior parts of the cerebellum through the tentorial notch.
Clinical presentation
- nausea and/or vomiting
- rapid progression toward a decreased level of consciousness and, eventually, death
Radiographic features
General imaging features include:
- flattening or reversal of the smile-shaped quadrigeminal cistern
- obliteration of the quadrigeminal and superior cerebellar cistern in severe cases
- "spinning top" appearance of midbrain due to bilateral compression of the posterior aspect of the midbrain 1
- may be associated with an infarct in the territory of posterior cerebral and superior cerebellar arteries due to arterial compression
- hydrocephalus as the result of the pressure of the cerebellum on the cerebral aqueduct