What is sinusitis? You get up in the morning feeling lousy, with a heavy head a feeling which Persists through the day wanting to sleep all the time, you're coughing and sneezing and tired and achy. You think that you might be getting a cold. Later, when the medicines you've been taking to relieve the symptoms of the common cold are not working, you finally drag yourself to the doctor. After listening to your history of symptoms, examining your face and forehead, and perhaps doing a sinus X-ray, the doctor says you have sinusitis. What are sinuses? Sinuses are hollow air spaces in the human body. When people say,"I'm having a sinus attack," they usually are referring to symptoms in one or more of four pairs of cavities, or sinuses,known as paranasal sinuses. These cavities, located within the skull or bones of the head surrounding the nose, include the: Frontal sinuses over the eyes in the brow area Maxillary sinuses inside each cheekbone Ethmoid sinuses just behind the bridge of the nose and between the eyes Sphenoid sinuses behind the ethmoids in the upper region of the nose and behind the eyes Each sinus has an opening into the nose for the free exchange of air and mucus, and each is joined with the nasal passages by a continuous mucous membrane lining. Therefore, anything that causes a swelling in the nose-an infection, an allergic reaction, or an immune reaction-also can affect the sinuses. Air trapped within a blocked sinus, along with pus or other secretions, may cause pressure on the sinus wall. The result is the sometimes intense pain of a sinus attack. Similarly, when air is prevented from entering a paranasal sinus by a swollen membrane at the opening, a vacuum can be created that also causes pain. What are the symptoms of sinusitis? The location of your sinus pain depends on which sinus is affected. Headache when you wake up in the morning is typical of a sinus problem. Pain when your forehead over the frontal sinuses is touched may indicate that your frontal sinuses are inflammed