What is Sinus?
A Sinus is a hollow, air filled cavity. Humans have four pairs of sinuses. 1) Frontal sinus (forehead Pain) 2) Maxillary sinus (behind cheeks ) 3) Ethmoid sinus ( between the eyes) 4) Sphenoid sinus (deep behind the ethmoids) The 4 pairs of sinuses are often described as a unit and termed as a "paranasal sinuses" A sinus infection occurs when a pathogenic microorganism (virus, bacterium or a fungus) grows within a sinus.