Definition of the pathology

Sinusitis is an inflammation of the lining of the sinuses. The sinuses are bony cavities (divided into 4 pairs) in the bones of the face. Each sinus communicates with the nasal cavities through small openings through which the mucus produced in the sinuses normally flows. Inflammation of the sinus lining, also called rhinosinusitis, is usually caused by a viral or bacterial infection. When a virus or bacteria spreads through the sinuses, the lining becomes irritated and swollen, which can block the sinuses. Mucus can no longer drain out of the nose normally, and microbes are able to multiply freely in this closed environment..