Digital image of the lower basal turn, taken from a surface preparation of an epoxy-embedded human cochlea. The black dashed line defines the OC length, which was 10.43 mm in this example. The thick radial lines indicate where radial sections were prepared to examine the SG and to measure the distances from the OC to the SG and modiolar wall. White dashed lines represent the SG (inner line), measured 6.11 mm at the approximate center of the Rosenthal’s canal (as estimated in the radial sections), and the modiolar wall (outer line) adjacent to the SG, which measured 6.78 mm for this specimen. The white lines show the tracings of radial nerve fiber trajectories that were used to define the frequency-matched coordinates on the OC and SG. Scale bar, 1 mm.