In subfalcine herniation, brain tissue is pushed against which structure?

• A. Falx cerebri (dura)
• B. Tentorium cerebelli
• C. Corpus callosum
• D. Pia mater

Answer: (A)

Subfalcine herniation occurs when the medial part of a cerebral hemisphere, typically the cingulate gyrus, is pushed under the falx cerebri, the dural fold that runs along the midline between the two hemispheres. The tissue is pressed against the inner surface of the falx cerebri. This is distinct from other herniations, such as transtentorial herniation where tissue is pushed against the tentorium cerebelli. The falx cerebri is the structure involved in this specific herniation, not the corpus callosum or pia mater.