Sinusology

This paper presents a brief history of the successive anatomical, physiological and pathophysiological concepts about the paranasal sinuses. Sinusology, the science of the paranasal sinuses, is founded on scientific work on the production of nitric oxide (NO) by the sinuses and on the evo-devo theory of their formation. The paranasal sinuses seem to develop after regression of the erythropoietic marrow in the maxillary, frontal and sphenoid bones and its replacement by cavities filled with gas, which escapes into the nasal fossae through the ostium. The sinus epithelium synthesizes NO continuously. The paranasal sinus cavities form a compartmentalized reservoir of NO, which is released discontinuously in boli after an opening of the ostium. Ostium opening can be induced by sound vibration, either internal (humming) or external (an acoustic vibration added to the in-breath). NO plays the role of an "aerocrine" messenger between the upper and lower respiratory tracts, reducing pulmonary vascular resistance and facilitating alveolar oxygen transfer into the bloodstream. Its physiological role in arterial blood oxygenation could be involved in speech and singing or be activated by physiological snoring during sleep. Rhinology, the science of the nose, in which the evo-devo concept distinguishes the respiratory and the olfactory nose, is now backed up by sinusology.