title: Use of phase contrast microscopy to determine the height of the organ of Corti in whole-mount preparations.
abstract: A technique has been developed to measure the height of the organ of Corti (OC) in the whole-mount preparations of the cochlear duct. The technique corrects for variations in the microscope system, such as the magnification of the objective lens and the mechanical properties of the fine-focus knob, as well as the refractive index of the embedding medium and the angle of specimens with respect to the optical axis of the microscope. At 11 percentage locations from apex to base, the height of the OC in ten chinchilla cochleas was measured at three positions: (1) the lateral edge of the inner hair cell (IHC); (2) the medial edge of the first row outer hair cell (OHC1); and (3) the lateral edge of the third row outer hair cell (OHC3). These measurements were compared to measurements made on radial sections from five other cochleas, with very good agreement at IHC and OHC3, and fairly good agreement at OHC1. The height at OHC3 varied almost linearly with percentage distance along the OC, ranging from 96 microns (apical end) to 51 microns (basal end). The height at the OHC1 varied from 77 to 49 microns, but did not vary linearly. The height of the IHC was relatively constant, from 50 to 60 microns, except at the basal end, where it decreased to 42 microns.
authors.forename: P J
authors.initials: PJ
authors.lastname: Baggot
authors.forename: B A
authors.initials: BA
authors.lastname: Bohne
authors.forename: D G
authors.initials: DG
authors.lastname: Bozzay
authors.forename: G W
authors.initials: GW
authors.lastname: Harding
mesh_terms: D000818:Animals; D002682:Chinchilla; D006652:Histological Techniques; D008858:Microscopy, Phase-Contrast / Q000295:instrumentation / Q000379:methods; D009925:Organ of Corti / Q000033:anatomy & histology* / Q000166:cytology