The analysis of the displacement of the pelvic girdle, during movements of the trunk in the anatomical orthogonal plans, was carried out by the technique of the cutaneous markers on two series of 7 male subjects and 7 female. The photographs made it possible to objectify angular displacements of reliable singular points and to observe that the abduction of hips determines, according to movements carried out, either a facilitation, or a limitation of displacements observed similar in the two series. The precise mechanism of these variations will have to be analyzed by later studies.