The falx cerebri is a sickle-shaped fold of the dura mater, a tough membrane that covers the brain. It extends vertically between the two cerebral hemispheres, providing structural support and separating them. This structure helps to stabilize the brain within the skull. The falx cerebri contains the superior sagittal sinus, a large vein that drains blood from the brain. It plays a crucial role in the venous drainage system, ensuring that deoxygenated blood is efficiently transported away from the brain. Overall, the falx cerebri is essential for both protection and support of the brain's anatomy.