One of the 8 bones that make up the cranium (skull).  It is a butterfly shaped bone with greater and lesser “wings.”  The sphenoid bones occupies most of the middle part of the skull and makes up the middle region of the cranial fossa.  The superior surface of the sphenoid bone contains the Sella Turcica  (which houses the pituitary gland) and the Chiasmatic Groove (optic groove).  It is the only bone that connects to all other bones in the cranium.  It’s movement is responsible to stimulating the pituitary gland to secrete its hormones.