Localization of the marginal zone of the tectorial membrane in situ, unfixed, and with in vivo-like ionic milieu.

In order to determine the normal positional relationship between the tectorial membrane and the organ of Corti, a preparation method was developed which made it possible to study the unfixed tectorial membrane in its normal position in relation to the cochlea and with in vivo-like ionic conditions. With this method, post-mortem changes visible with the light microscope were detectable after 60 to 90 min instead of the normal 30 min. When endolymph of artifical endolymph are present in the scala media, the marginal zone lies in close contact with the surface of the organ of Corti. If the endolymph is replaced by artificial perilymph, first the marginal zone of the tectorial membrane, and later the whole membrane shrinks. At this stage, latex particles suspended in the perilymph are free to enter the subtectorial space.