26 children of both sexes (range of age between 9 and 15 years) were clinically examined to reveal position of the pelvis and ranges of hip joint rotations. Children suffering from fixed pelvic nutation were selected to participate in experiment. We searched for cause of the fixed pelvic nutation and ranges of hip joint rotations were goniometrically measured before and after treatment. Results show that there are four main causes of fixed pelvic nutation and so pelvic dysfunction, syndrome of the coccyx and pelvic floor muscles, dysfunction of the left ankle and, more rarely, dysfunctions of the spine. In all cases, symetrisation of hip joint rotations followed treatment in the place eliciting fixed pelvic nutation.

        Key words: fixed nutation of the pelvis, hip joint rotations, sacroiliac joint, chains of