Abstract
We show that the vertex deviation of young stars is a natural consequence of the epicyclic character of the stellar motions in the galaxy. If the stars are young enough (ages of about 1.8 x 10^7 years), the vertex deviation is about -30° and it is not much affected by the formation of stars in an arm or their systematic velocities at birth; older stars (ages of about 6.5 X 10^7 years) suffer the modelling effects of their birth conditions.
