The hypotympanum and infralabyrinthine cells in chronic otitis media. Despite the localization implied by the term "chronic otitis media," little attention has been paid to the role of the hypotympanum in chronic active otitis media. Most authors have emphasized the role of recurrent cholesteatoma or unexenterated cells in the mastoid cell system as causes of recurrent disease. Seven cases are reported in which clinical evidence indicated that recurrent chronic otitis media was limited to the hypotympanum and infralabyrinthine cell system. In the five cases in which revision surgery was done, exenteration of this area resulted in an asymptomatic ear. The anatomy, radiographic evaluation, and surgical approach to the hypotympanum are reviewed. Careful inspection of the hypotympanum in primary surgery for chronic ear disease and exenteration of the hypotympanic and proximal infralabyrinthine cell tract are advocated when these regions contain cholesteatoma or extensive granulomatous disease. 