The ethmoidal air cells (also ethmoidal sinuses or ethmoid sinuses, latin: cellulae ethmoidales) are multiple thin walled cavities located within the ethmoidal labyrinth. They are situated between the upper part of the nasal cavity and the orbit. The orbital plate of the ethmoid separates the ethmoidal air cells from the orbit.
The ethmoidal air cells are subdivided into anterior, middle and posterior groups on each side, which are separated by the basal plate of the middle nasal concha.
The arterial blood is supplied to the ethmoidal air cells via the following vessels:
The venous drainage from the ethmoidal air cells is provided by the sphenopalatine and ophthalmic veins.
The sensory nerve supply to the mucosa lining the ethmoidal air cells is provided by the following nerves: