The invention relates to a prosthesis cup (1), in particular for a shoulder prosthesis, comprising a shell (2) substantially in the shape of a hollow spherical cap defining a concave inner surface (3). The shell (2) includes anchoring means which project from the inner surface (3) and are shaped to penetrate a bone and anchor the cup (1) therein. The invention is characterised in that the anchoring means are shaped to trigger the rotation of the cup (1) as they penetrate the bone.
