Chronic sinusitis

The sinuses are surrounded by bone and cartilage and lined with a mucous membrane. Sinusitis occurs when the membranes becomes inflamed and painful, which may be a result of a blocked sinus opening.

Chronic sinusitis is often caused by inflammation and blockage due to physical obstruction such as a deviated septum, misformed bone or cartilage structures such as the nasal conchae (turbinates), or blockage by nasal cysts or polyps.