EPITYMPANIC DIAPHRAGM IN THE NEWBORN

A series of 80 temporal bones included four specimens from infection-f ree new-born children. The microdissections showed that the epitympani c diaphragm in the new-born consists, in addition to the position fixe d ligamental folds and ossicles, of only two position changing duplica te folds. These were the lateral incudomalleal fold, separating the up per and lower lateral attics, and the tensor fold, separating the ante rior epitympanum from the supratubal recess. All other duplicate folds present during the fetal development had disappeared, a finding in ac cordance with the study on fetuses by Hammar in 1902 and with our own microdissection findings in normal adult temporal bones. Folds in othe r locations, even if until lately considered as participants of a norm al epitympanic diaphragm, are of inflammatory origin. (C) 1998 Elsevie r Science Ireland Ltd. All rights reserved.