Histopathologic study of the human temporal bone entails microscopic examination and analysis of a series of histologic sections. This is currently the most effective method for observing the pathologic conditions of MD by examining the entire inner ear. Complete temporal bone histopathology cannot be replaced by either clinical pathologic study of small biopsy specimens obtained during surgery, or experimental animal studies that can create endolymphatic hydrops but not create MD. We believe that the histopathologic findings together with clinical information on MD is valuable in enhancing our understanding of the pathophysiology of the inner ear in MD. For example, a hypoplastic VA and ES in MD seem to indicate that there may be congenital predisposing factors in the development of MD. The exact pathologic findings characteristic of MD remains unclear, however. Many of the temporal bone specimens were obtained years after patients were diagnosed with MD and those specimens were involved with moderate postmortem changes. For these reasons, further collection of temporal bone specimens with fewer postmortem changes, obtained within a shorter premortem time period between occurrence of the disease and the time of the patients' death, and from patients with a well-characterized clinical history of MD, is imperative. Contemporary temporal bone studies now include in situ hybridization histochemistry or polymerase chain reaction (PCR) analysis for protein, enzymes, or viral antigens that can be directed at specimens from patients with MD [54,55]. It is hoped that in the near future such advanced research studies with human temporal bone histology sections will support and enhance the significant contribution of temporal bone histopathology to clinical otology.