The acetabular cup comprises a screw-impacted ring and a core. The ring (1) has a wide indentation (1a) formed on one side, extending from its peripheral edge as far as the polar zone, the peripheral zone having in the vicinity of the said indentation (1a), and in a symmetrical fashion, roughened parts (1b) which are able to implant themselves in the cornua of the osseous acetabulum in order to afford a primary stability. <IMAGE>
