ABSTRACT
The nasal cycle is associated with a number of physiological changes in the alternating sides of the nose. Studies of nasal physiology are currently being undertaken using acoustic rhinometry and rhinoresistometry. The most important factors contributing to the maintenance of the normal physiology of the paranasal sinuses and their lining mucous membranes are mucous secretion, clearance and ventilation. Ventilation and drainage of the frontal and maxillary sinuses depend primarily upon the patency of both the actual sinus ostia and their ethmoid prechambers that connect the ostia with the nasal cavity via the anterior ethmoid. The nasal mucosa has an abundant blood flow, which is derived from both the internal and the external carotid arterial systems. Both computed tomography (CT) and magnetic resonance imaging both demonstrate sinonasal mucosa. The high incidence of asymptomatic abnormalities of the paranasal sinuses observed during routine CT imaging of the head is well known.
