<P> The bony walls of the orbital canal in humans do not derive from a single bone , but a mosaic of seven embryologically distinct structures : the zygomatic bone laterally , the sphenoid bone , with its lesser wing forming the optic canal and its greater wing forming the lateral posterior portion of the bony orbital process , the maxillary bone inferiorly and medially which , along with the lacrimal and ethmoid bones , forms the medial wall of the orbital canal . The ethmoid air cells are extremely thin , and form a structure known as the lamina papyracea , the most delicate bony structure in the skull , and one of the most commonly fractured bones in orbital trauma . The lacrimal bone also contains the nasolacrimal duct . The superior bony margin of the orbital rim , otherwise known as the orbital process , is formed by the frontal bone . </P>
what is the name of the bone that makes up most of the posterior surface of orbit
the sphenoid bone