Organ of Corti surface preparations for computer-assisted morphometry

This paper describes a relatively rapid method (67 h) for producing surface preparations of the organ of Corti that are suitable for a computer-assisted morphometric analysis of cochlear hair cells. On day 1, a cochlea was fixed in OsO4, dehydrated in ethanol and infiltrated with an Epon-like plastic (Medcast). On day 2, the Medcast within the cochlea was polymerized at 60 degrees C in an oven. On day 3, the complete organ of Corti was dissected into approximately 20 segments which were trimmed and mounted on a slide in Medcast. Two 400 mesh transmission electron microscope grids are mounted at the apical and basal ends of the organ of Corti. These grids served as reference points for the establishment of an independent X, Y coordinate system on the slide by a computer-assisted light microscope. The segments were permanently attached to the slide by polymerization of the Medcast at 60 degrees C for approximately 15 h. At the beginning of day 4, the organ of Corti surface preparation was ready for examination by light microscopy or could be further sectioned and examined by transmission electron microscopy.