The ethmoidal nerves, which arise from the nasociliary nerve, supply the ethmoidal cells; the posterior branch leaves the orbital cavity through the posterior ethmoidal foramen and gives some filaments to the sphenoidal sinus. There are two ethmoidal nerves on each side of the face:
This article incorporates text in the public domain from page 888 of the 20th edition of Gray's Anatomy (1918)
