In its lower portion the falx cerebelli diminishes very rapidly in height and as it descends, it can divide into two smaller folds or diverging limbs, which are lost on the sides of the foramen magnum. Other variations such as duplication, triplication, absence, and fenestration are much less common.
The falx cerebelli's lower portion shrinks significantly in height as it descends, eventually splitting into two smaller folds that disappear on the sides of the foramen magnum.  Variations such as duplication, triplication, absence, and fenestration are much rarer.