Measuring the tilt of the pelvis

A simple and easy-to-use device for measuring forward-backward rotation of the pelvis is introduced. It consists of a small rod, which can be attached to the skin of the sacrum. This 'antenna' follows the movements of the pelvis. The article describes the use of this device and the calibration of this method; to this end the antenna position is related to the 'actual' rotation of the pelvis, defined as the rotation of a set of easily palpable landmarks. Each landmark is found by palpation and its spatial coordinates are measured with a palpator. The results show that pelvic rotation with respect to a reference position can be obtained with an inaccuracy of 10%. With special care this can be reduced to 5%.