The sphenoid bone (os sphenoidale) has been described as butterfly or bat-shaped, and is a complex bone situated as a wedge or keystone in the base of the skull. Hover over the image1 for a view of the location of this bone.
The sphenoid bone has a superior depression called the sella turcica, Latin for "turkish chair" where the hypophysis or pituitary gland is found.
On its inferior aspect the sphenoid bone presents with two thin wing-like plates called the lateral and medial pterygoid plates or lamina (see the area with the letter "H" in the accompanying image)
Images modified from "De Humanis Corporis Fabrica" by Andreas Vesalius.