The structure of the quiet solar atmosphere is dominated by effects due to the magnetic field distributions produced by field concentrations at the supergranual boundary regions. This effect has been studied by previous workers (Kopp and Kuperus, 1968, Kopp, 1972), and is also evident in the enhanced intensity at the SBR's of spectral lines formed in the upper chromosphere and transition region. An attempt is being made to evaluate the field distributions more precisely, taking into account the physical processes involved in the interactions between the field and plasma, and thereby to predict the intensity distributions expected for the EUV spectra. This work is not yet complete, but some important results can be foreseen.