Subfalcine Herniation

Excerpt

Herniation occurs when brain tissue is displaced across a structure within the cranium. Subfalcine herniation is the most common form of intracranial herniation and occurs when brain tissue is displaced under the falx cerebri. The cingulate gyrus is herniated under the falx, and if progression occurs, other areas of the frontal lobe are involved.

Once the fontanels close in infancy, the cranium becomes a closed rigid structure with a fixed volume containing three components; the brain, the cerebrospinal fluid (CSF), and intracerebral blood. The Monroe-Kellie doctrine states that intracranial volume is constant, and an increase in the volume of one component will cause a decrease in the volume of one or both of the others. This change can have significant effects, such as decreased cerebral blood flow or herniation of brain tissue. When herniation occurs, the location of the herniation determines the presenting symptoms and the clinical outcomes.