FIG. 2.

Photomicrographs of the spiral ganglion in the upper basal turn from representative cases aged 2, 61 and 91 years, as indicated. The black arrow in each large panel points to the bundles of peripheral axons of cochlear nerve fibers in the osseous spiral lamina. The approximate outline of Rosenthal’s canal is shown by the dashed line in panel B. Scale bar in C applies to all three large panels. The small inset in each panel shows a high-power view of some of the cells in Rosenthal’s canal. The red arrowheads indicate spiral ganglion cells, characterized by a diffuse pink cytoplasm with a darker centrally located nucleus. The black arrowheads point to Schwann-cell nuclei: their cytoplasm is not easily seen.