The ethmoid bone is a bone of very spongy substance, somewhat irregularly cubical in shape, lying at the root of the nose, between the two orbits or eye-sockets, and forming part of the bony wall of both. The segment of the ethmoid bone which forms part of the inner wall of the orbital cavity is called the orbital plate, while another segment, forming the roof and back part of the septum of the nasal cavity is called the perpendicular plate. Two irregularly shaped, shell-like projections from the ethmoid bone are called the superior and middle turbinate (conchae), and form ledges on the inside wall of the nasal cavity. Research Ethmoid Bone