Your Sinusitis Guide

The paranasal sinuses are air-filled cavities inside the bones of the skull. They are located on either side of the nose, behind and between the eyes, and in the forehead; there is also one further back in the head. They probably function to reduce skull weight and to enhance vocal resonance. They also have a protective function. However they may become infected, leading to sinusitis with symptoms such as a blocked nose, post-nasal drip and even sinus headaches. But sinusitis can also be caused by allergens and is often associated with other respiratory conditions.