Pathogenesis of mucocele of the frontal sinus. As a pneumatization anomaly of the sinuses

Abstract

Pathogenesis of the mucocele was discussed on the basis of the author's pneumatization theory. The construction of the pneumatic cavities are considered to be divided into two parts, i.e. the canal and the antrum. The Euchstachian tube, the nasofrontal duct and the bronchus correspond to the canal part of the pneumatic cavity.From the study on the development of the bronchi and the alveoli, the author concluds that the canal part (bronchus) may become atrophic, if the antrum (alveoli) enlarges (emphysema), and on the other hand, the canal part may become hypertrophic and dilate (broncuiectasis), if the antrum becomes apneumatic.This mechanism can be applied to the relationship of the frontal sinus and its duct. Therefore, in the large frontal sinus the duct may become narrowed and then obliterated.However, roentgenological study of 12 cases of frontal sinus mucocele indicates that the mucocele of the frontal sinus does not occur only in the large frontal sinuses, but also in the moderate large sinuses, by which the over development of the anterior ethmoidal sinuses were confirmed. Over development of the anterior ethmoidal sinuses might cause the constriction of the nasofrontal duct The author emphasises that as one of the etiological factors of mucocele of the frontal sinus the over development of the frontal sinus and the ethmoidal sinus, namely the pueumatization anomaly of the paranasal sinuses, should be considered.