What are the sinuses and what do they do?
What are sinuses? The sinuses are hollow cavities within the bones of the skull. They lie adjacent to the nasal cavity and are therefore anatomically named the “paranasal” sinuses. Four sets of sinuses lie on each side of the nasal cavity: frontal, ethmoid, maxillary, and sphenoid sinuses. The frontal sinuses occupy the bone over the eyes in the forehead while the maxillary sinuses are under the eyes in the cheekbones. The ethmoid sinuses are actually a collection of sinuses, like a honeycomb, which lie between the eyes. The sphenoid sinuses are placed behind the nasal cavity and eyes, near the center of the head. The paranasal sinuses are similar to rooms lying off a main hallway, the nasal cavity. Air flows up and down this hallway as we breathe in and out through our noses. A special “wallpaper” lines the nasal “hallway” and each sinus “room.” This lining is the mucosa, which swells and thickens with irritation or inflammation. The sinuses are connected to the hallway through very n
