In brain herniation, brain tissue is displaced through which structure?

• A. Through the Cerebral Fissures
• B. Through the Foramen Magnum
• C. Downward Upon the Falx Cerebri
• D. Upwards Onto the Basilar Cortex

Answer: (B)

When intracranial pressure climbs, brain tissue can be squeezed downward toward the base of the skull. The foramen magnum is the large opening at the skull base through which the spinal cord passes; if cerebellar tissue (often the tonsils) is pushed through this opening, it causes downward herniation through the foramen magnum. This position brings brainstem structures into the spinal canal and can severely affect vital centers, leading to dangerous breathing and heart rate problems. Other patterns describe different routes, such as tissue being squeezed under the falx cerebri or through the tentorial notch, but the scenario described here specifically involves displacement through the foramen magnum.