Did you know there is a butterfly that lives inside your head and when he flaps his wings, he is cleaning your brain and spinal cord? Sounds crazy but no, I have not lost my mind. That butterfly is more commonly known as the sphenoid bone. This bone is very unique as it sits inside of the skull and is the only bone to form a joint with every other bone of the skull, including the base of the skull. When we inhale, this joint flexes, and when we exhale, this joint extends. This pumping motion pushes cerebrospinal fluid throughout your central nervous system in order to remove metabolic waste and keep it from building plaque.