Recent scintillation observations have disclosed the existence of sheetlike electron density irregularities aligned along L shells in the auroral zone ionosphere. In this paper we explicit the aspect sensitivity of phase scintillation to identify the dominant three-dimensional configuration of irregularities in four latitude/time zones; (1) equatorward of the high-latitude scintillation boundary on the nightside of the earth. (2) poleward of the nightside boundary, (3) equatorward of the boundary on the day side, and (4) poleward of the dayside boundary. We find the sheetlike irregularities to be confined to region 2, with few exceptions. The dominant configuration in the other zone 4, is that of axially symmetric rodlike irregularities aligned along the magnetic field.