The ethmoid bone. Superior view. The etmoid bone has three parts: cribriform plate, ethmoid labyrinth, and perpendicular plate. The crista galli is seen in the midline of the cribriform plate, which supports the olfactory bulbs and is perforated by multiple foramina for the passage of the olfactory nerves. The cribriform plates are bounded laterally by the vertical lateral lamella and ethmoid labyrinth. The lamina papyracea forms the medial wall of the orbit. (Image courtesy of JC Fernandez-Miranda)