Picture of Sinuses
Sinuses are hollow, air-filled cavities that are located throughout the skull. There are several sets of sinuses in the head. The maxillary sinuses are behind the cheeks. The ethmoid sinuses lie under the inside corners of the eyes. The sphenoid sinuses are located behind the ethmoid sinuses. The frontal sinuses lie behind the forehead above the eyes. The sinuses are lined with mucus-producing membranes that help guard against pathogens, debris, and pollutants.
Text Reference: "Sinus Anatomy." American Rhinologic Society.