Sinuses are the hollow air chambers found in the face. The sinuses produce mucus, which cleans harmful particles out of the air we breathe. The frontal sinuses are located above the eyes, in the brow area of the face. The ethmoid sinuses are between the eyes and the bridge of the nose. The sphenoid sinuses are located behind the ethmoid sinuses, and the maxillary sinuses are in the cheekbones. While our sinuses are very useful, for many they are a cause of infection, inflammation and pain.