Around our nose region, on the inside, are certain hollow cavities
called the sinus cavities or simply sinuses.
These cavities are located behind the nose, the cheeks and brow
regions. These cavities secrete mucus into the nasal duct. The purpose
of this mucus is to moisten, filter and regulate the temperature of
the air that we breathe in.
The way that the mucus is secreted into the nasal duct is through
small openings in the sinus cavities through which they drain their
The mucus is created by the mucus membrane which lines these sinus
cavities, including the openings.
In case of sinus infections, this mucus membrane which lines the
cavities becomes inflamed or swollen. The effect of this is that the
openings of the cavities (which it also lines) get closed due to the
Once these openings get blocked, the mucus that is being continuously
secreted by the linings cannot be drained from the cavities. Over time
this collected mucus in the sinus cavities becomes a breeding ground
for viruses which leads to infection called sinus infection.