Abstract: A head for a surgical introducing tool includes a cup holding element for releasably holding an acetabular cup, and a retaining element for preventing undesirable release of the acetabular cup from the holding element. The holding element is receivable in a space defined by an articulating inner surface of the acetabular cup and includes a seal and an air passage by which the acetabular cup can be held to the head by vacuum. The retaining element is positioned radially outwardly relative to the holding element and dimensioned to be a close fit with the acetabular cup. In use, relative tilting of polar axes of the head and the acetabular cup is prevented or limited by the retaining element while the cup is held by the holding element, so that accidental separation of the cup from the holding element is prevented.