the vagus nerve. Anatomical relations The falx cerebri is situated in the longitudinal fissure, in between the cerebral hemispheres. The corpus callosum lies immediately inferior to the lower (free) margin of falx cerebri. Dural venous sinuses The superior sagittal sinus is contained in the superior margin of the falx cerebri and overlies the longitudinal fissure of the brain. The inferior sagittal sinus is contained in the inferior free margin of the falx cerebri and arches over the corpus callosum, deep within the longitudinal fissure. The straight sinus courses along the juncture of the falx cerebri and cerebellar tentorium. Anatomical variation Total or partial agenesis of the falx cerebri may occur, and may result in adherence of the cerebral hemispheres across the midline. Agenesis is usually associated with other developmental complications; falx cerebri agenesis in absence of other neural symptoms is exceedingly rare. Microanatomy The falx cerebri contains blood vessels, and nerves. Clinical significance Calcification Calcification of the falx cerebri is more prevalent in older patients, often without a determinable cause, and without pathogenic symptoms. Meningioma Falcine meningioma is a meningioma arising from the falx cerebri and completely concealed by the overlying cortex. Falcine meningioma tends to grow predominantly into one cerebral hemisphere but is often bilateral, and in some patients the tumor grows into the inferior edge of the sagittal sinus. However, although much information is available regarding meningiomas, little is known about falcine meningiomas. Surgical landmark The falx cerebri is a significal surgical landmark for access of the lateral ventricles via the interhemispheric transcallosal approach; agenesis (complete or partial) of the falx cerebri results in the adherence of the cerebral hemispheres, blocking midline transcallosal surgical access to the ventricles. Subfalcine brain herniation Subfalcine herniation of the cingulate gyrus may occur following traumatic brain injury. Additional images See also Falx (disambiguation), other parts of the anatomy with names including "falx" References External links Meninges