Posterior ethmoidal foramen
The posterior ethmoidal foramen is a small opening in the ethmoid bone. It transmits the posterior ethmoidal artery, vein and nerve which supplies the posterior ethmoidal and sphenoid sinuses.
The distance between the anterior and posterior ethmoidal foramina is 12 to 15 mm. The distance between the posterior ethmoidal foramen and the optic canal is usually 3 to 7 mm.