Are there typical corrugation scales in our Galaxy ?

The crinkly structure of the H I centroid distribution of galactic spiral arms was investigated and hints of azimuthal corrugations along most of the galactic spiral arms were found from H I observations. Three distinct corrugation scales seem to exist: class 1 (lambda in the range of 1-2 kpc), class 2 (lambda in the range of 4-8 kpc), class 3 (lambda less than 13 kpc). The scale length within each class does not depend on radius in the Galaxy, whereas the corrugation amplitude does and increases with the thickness of the H I distribution. These corrugations were also found in the distribution of O and B-stars, stellar associations and H II regions. There is also slight evidence for a meandering of H I spiral arm centroids in the galactic plane. In the radial direction, a corrugation pattern of the galactic plane is identified with a scale length of about 4 kpc. This radial corrugation effect is also confirmed by H II and CO data.