Abstract: A cementable thigh section of an acetabular prosthesis that has a shaft tapering toward its lower end, and on whose upper end is formed a flange-like support collar. Disposed in removable fashion below the support collar is an elastic spacer ring that at least partially covers the support collar. Worked in from the upper end of the thigh section is a boring that preferably branches out into branch borings, that comes out from the thigh section in the upper shaft portion, and serves for bringing the bone cement into the intermediate space between bone wall and thigh section after the thigh section is emplaced in the bone cavity.