Notice also the cerebellum filling the quadrigeminal plate cistern and ambient cisterns from an ascending transtentorial herniation. Similarly, anterior displacement of the middle cerebral artery occurs in anterior alar herniation. A sagittal MRI can also demonstrate anterior or posterior displacement over the sphenoid bone. Clinical complications of alar herniations have not been discussed extensively most likely due to the association of other herniations and their clinical complications. Although there can be shift in this location, it may be more academic especially in the presence of other herniations.
Subfalcine herniations occur as the brain extends under the falx in the supratentorial cerebrum.
This may be the most common form of herniation although many authors in the past suggest transtentorial herniation is the most common. Perhaps this is due to the multitude of clinical symptomatology and urgency involved in transtentorial herniations. While subfalcine herniations often occur in conjunction with transtentorial herniation or in isolation. Presence however, does not necessarily lead to severe clinical symptomatology or alarm. Subfalcine herniations can present clinically as headache.