A falcine sinus is a venous channel that lies within the falx cerebri connecting the vein of Galen and the posterior part of superior sagittal sinus.[1] It is normally present during fetal development and involutes after birth. The presence of a falcine sinus has been associated with a vein of Galen malformation and other vascular anomalies. The persistence of a falcine sinus after the neonatal period was previously thought to be rare, but has recently been described to be present in up to 5% of all people,[2] appearings in approximately 2.1% of CT examinations of adult patients. Some authors have studied the plexus rather than the sinus, a rare form of the venous pathway between the layers of the cerebral falx, which connects the superior sagittal sinus with the inferior sagittal sinus and the straight sinus.[3]