Mobility of the pubic symphysis. Measurements by an electromechanical method.

Two pins were inserted, one on each side of the symphysis in 15 volunteers and four cadavers. Movements between the pins were registered by two transducers. Symphyseal movements were small. Translations in the transverse and sagittal directions were around or below 1 mm. Rotations in the frontal and sagittal planes were below 1.5 degrees. Movements in the vertical direction were around 2 mm in both sexes. Higher values were observed in multiparous than in nulliparous volunteers.