The term "frontoethmoidal" refers to a region or structure that involves both the [[frontal sinus]] and the [[ethmoid sinus]]. The frontal sinus is located in the frontal bone, specifically in the forehead region, while the ethmoid sinus is a group of air cells within the ethmoid bone between the eyes. When used together, "frontoethmoidal" typically describes an anatomical area or condition that involves both the frontal and ethmoid sinuses.