Sphenoid Bone

The "sphenoid bone" is wedged between several other bones in the front of the cranium. It consists of a central part and two wing-like structures that extend sideways toward each side of the skull. This bone helps form the base of the cranium, the sides of the skull, and the floors and sides of the orbits (eye sockets). Along the middle, within the cranial cavity, a portion of the sphenoid bone rises up and forms a saddle-shaped mass called "sella turcica" (Turk's saddle). The depression of this saddle is occupied by the pituitary gland, which hangs from the base of the brain by a stalk. The sphenoid bone also contains two "sphenoidal sinuses," which lie side by side and are separated by a bony septum that projects downward into the nasal cavity.