A type of
paranasal sinus (a hollow space in the bones around the nose). There are two, large frontal sinuses in the frontal bone, which forms the lower part of the forehead and reaches over the eye sockets and eyebrows. The frontal sinuses are lined with cells that make
mucus to keep the nose from drying out.
mucus (MYOO-kus)
A thick, slippery fluid made by the membranes that line certain organs of the body, including the nose, mouth, throat, and vagina.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)paranasal sinus (PAYR-uh-NAY-zul SY-nus)
One of many small hollow spaces in the bones around the nose. Paranasal sinuses are named after the bones that contain them: frontal (the lower forehead), maxillary (cheekbones), ethmoid (beside the upper nose), and sphenoid (behind the nose). The paranasal sinuses open into the nasal cavity (space inside the nose) and are lined with cells that make mucus to keep the nose from drying out during breathing.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)
