The glomus tympanicum: a middle ear chemoreceptor?

Negative pressure in the middle ear has been identified as an important factor in the pathogenesis of middle ear disease. Unfortunately, to date, the physiological mechanisms that control middle ear pressure are poorly understood. Recent interest has focused on the possible role of carotid body-like tissue in the middle ear (the glomus tympanicum) as a chemoreceptor for changes in the gas composition of the middle ear. From the few anatomical studies of normal glomus tissue in the temporal bone it would seem that glomus bodies may not be consistently present in the middle ear. In this study, glomus bodies were sought in histological preparations of the promontory mucosa and tympanic plexus. It was found that the glomus tympanicum is only occasionally present in the middle ear mucosa, and thus a chemoreceptor role specific to the middle ear is unlikely.