The sinuses are air-filled cavities within the bones of the skull, which serve no other purpose than to make it a lighter burden for the neck to bear. No cavity in the body can afford to be unprotected, so the sinuses are lined with delicate membranes that connect up with those lining the nose. The membranes are there to supply blood and immune cells to the sinus cavities.

Since these cavities are rather isolated, peaceful cul-de-sacs that usually remain free of infection or inflammation, most people are unaware that they even exist. When they do become infected or inflamed, however, they can cause a gnawing pain in the face which makes the location of the sinuses all too clear. And if the problem does not clear up of its own accord, but requires medical attention, their relative inaccessibility within the skull becomes something of a disadvantage because they are not open to direct treatment. Antibiotics taken by mouth, which are carried to the membranes of the sinus cavities in the blood, are the usual form of treatment.

Most cases of sinusitis stem from an infection that begins in the nose and spreads outwards. However, allergic reactions in the nose can also spread to the sinuses, producing a headache over the eyes, if the frontal sinuses are involved, or an aching in the cheeks if the maxillary sinuses are affected.

There is one very simple treatment that is worth trying for sinusitis. First, take a deep breath in. Then hold your nose, shut your mouth and blow hard. This creates high pressure in the nasal cavity, which may open up the blocked passages to the sinus cavities.