This will be more fully addressed in Chapter 10, when we discuss the newer techniques of functional sinus surgery which normalize the sinuses to their proper function. If something is in the way of the normal drainage pattern, mucus is blocked which can lead to a sinus infection. The mucus blanket must have normal contents and be of a normal amount. Part of what makes up the mucus blanket are enzymes that fight infection, and if these are missing, sinus infection may result. If there is an increase in mucus produced, this too can lead to infection.
Hair cells move mucus toward the sinus ostia.
The interior of the nose is also lined by hair cells, which must be functioning normally to have proper sinus drainage. Anything that impairs the normal motion of hair cells may result in a nasal or sinus infection. For example, hair-cell motility is impaired in cystic fibrosis sufferers. These patients are plagued with chronic sinus infections, as they are unable to normally clear the mucus in their nose and sinuses. These three factors are interrelated.