air-filled cavities (spaces) located in your forehead, cheekbones and behind the bridge of your nose. The sinuses produce a thin mucus that drains out of the channels of the nose. When a sinus becomes inflamed, usually as the result of an allergic reaction, a tumor or an infection, the inflammation will prevent the outflow of mucus and cause a pain similar to that of a headache.
Air-filled cavities located above, beside and behind the nose and connected to the nose by tiny passages that carry sinus mucous into the nose. Sinuses serve as resonating chambers for speaking and singing. They also serve to reduce the weight of the skull by replacing dense bone with air-filled chambers.
Leaf sinuses are the area between lobes. Maples and oaks are typical examples of trees with "lobes" and "sinuses". [To return to previous page, click your browser's BACK button then scroll through the page to your last location