The diagnostic probe can be inserted into a vaginal or rectal body endo-cavity of the human body so as to measure the displacement of the walls of the endo-cavity and organs that surround the endo-cavity and so as to measure the displacement and the passive and active resistance of at least one muscle of the perineum. The diagnostic probe includes at least one endo-cavitary body provided with at least two pressure sensors arranged in the same plane and acting either in the same direction or in two opposite directions. The endo-cavitary body can be deformable without opposing resistance and matching the walls of the endo-cavity. The endo-cavitary body includes at least one device for measuring the displacement of the endo-cavitary wall along the three axes X, Y and Z.