In order to fine the observational restrictions for theoretical models explaining curvatures of extragalactic jets, tails, or lobes, a list of 365 objects has been extracted from published data. Radio sources exhibiting both jets curved in the same direction (called typeV) are equally frequent as those exhibiting them with opposite directions. Among the last antisymmetric types, two possibilities are considered: when jets draw a clockwise (typeS) or counterclockwise (typeN) image. TypesS andN are not only equally frequent as expected, but they do not have preferred locations in the sky. At least at large scales, once a jet is thrown out, it has an equal chance to be sent in any direction, independently of the one followed by its twin counterjet.