Microorganisms of the nose and paranasal sinuses.

The endogenous normal flora of the nose and paranasal sinuses works to create an environment of homeostasis within the region. This homeostasis can be interrupted by eliminating the anatomic barriers created by the skin, bone, and mucosa, such as after trauma and/or surgery; by altering the atmosphere of the surroundings, such as the creation of an anaerobic environment by obstruction of the sinus ostia or foramina; or by a change in the normal flora of the region. To fully understand the microbiological environment of this region, the normal flora of the nose and paranasal sinuses must be understood.