The ethmoid bone is an unpaired cranial bone that is a significant component of the upper nasal cavity and the nasal septum. The ethmoid bone also constitutes the medial orbit wall.

Where are the ethmoid and sphenoid bones?

The most posterior is the sphenoid sinus, located in the body of the sphenoid bone, under the sella turcica. The ethmoid air cells are multiple small spaces located in the right and left sides of the ethmoid bone, between the medial wall of the orbit and lateral wall of the upper nasal cavity.

What is special about the ethmoid bone?

The ethmoid bone is a cube-shaped bone located in the center of the skull between the eyes. It helps form the walls of the eye socket, or orbital cavity, as well as the roof, sides, and interior of the nasal cavity. Very light and sponge-like in texture, the ethmoid bone is one of the most complex bones of the face.