  We analyse the global structure of the old stellar discs in 34 edge-on spiral
galaxies. The radial and vertical exponential scale parameters of the discs are
obtained by applying an improved two-dimensional decomposition technique to our
I-band photometry. We find a clear increase in the disc scaleheight with
maximum rotational velocity, in accordance with observations of the stellar
velocity dispersions in galaxy discs. The range and maximum of the intrinsic
flattening of the disc light seem to increase with both maximum rotational
velocity and total HI mass. We use the disc flattening to estimate the disc
contribution to the maximum rotational velocity, resulting in an average of
57+-22 percent. The disc light distributions are further investigated for the
presence of radial truncations. We find that the radial light distributions of
at least 20 spirals are truncated, corresponding to 60 percent of the sample.
For small scalelength spirals, which are the most numerous in the local
Universe, the results suggest that the average ratio of disc truncation radius
to disc scalelength is at least four.
