The epitympanic mucosal folds were studied in 250 randomly selected fresh temporal bones and were found to be only rudimentary structures in normal ears, but had significant variations in abnormal ears. Pathological changes of the mucosal folds are a part of attic disease. In combination with tympanic membrane retraction, mucosal fold pathology seems to cause obstruction of the tympanic isthmus. Recognition of an air diffusion disturbance within the middle ear cleft pneumatic system at the area of the tympanic isthmus produced by these folds is important in the understanding of various middle ear diseases.
Aimi K. The Clinical Significance of Epitympanic Mucosal Folds. Arch Otolaryngol. 1971;94(6):499–508. doi:10.1001/archotol.1971.00770070799004