Subfalcine herniation = cingulate gyrus slides under falx cerebri (rarely causes ACA compression)
Transtentorial Herniation - can be uncal (mesial temporal lobe displacement) OR central (thalamus and midbrain through tentorial notch).
Cerebellar Tonsillar Herniation - downward displacement through foramen magnum (normal variant = tonsillar ectopia or low lying tonsils (as in chiari malformation))
ISO craniotomy one can have extracranial / extracalvarial herniation (should not be like a mushroom or indicates opening too small) or paradoxical herniation (where ICP is lower than atmospheric)