Study of the mesenchymal clearance factor and its importance in the middle ear pneumatization process in rat and in man.

An histological study on human and rat embryos and foetuses is presented. In all specimens middle ear pneumatization depended on the correlation between the tubal epithelium development and the mesenchymal absorption. The study of the mastoid pneumatization implies a conceptual development of the chronic otitis media pathogenesis and therefore represents a problem as old as otology itself. It is interesting to recall that the first otologist reached a conceptual idea of chronic otitis media long before the acute one. The initial differentiation was established depending on the duration of the discharge. It is evident that this finding was not sufficient to define chronic otitis, and as R. Bartual (1970) points out, the persistence of a tympanic membrane perforation was later used by the early otologist to differentiate the chronic otitis from the acute one.