Stationary plane-parallel vortex flows of an ideal gas are considered. Qualitative flow patterns are studied in the neighborhood of the point at which the sonic line is orthogonal to the velocity vector and in the neighborhood of the point of the sonic line at which the acceleration is zero. The results, together with those of Shifrin provide an exhaustive answer to the question of possible flow patterns in the neighborhood of the point at which the sonic line is orthogonal to the velocity vector, and testify to the wide variety of possible flow types in the neighborhood of the point where the acceleration is zero.