A prosthetic head (1) comprises: a body (10) having the shape of a cup shaped as a hemispherical cap provided with an external surface, an internal surface and a lower edge (19) shaped as a circumference, fixing means to fix the prosthetic head to the cotyle, and a projection (11) abutting from the internal surface of the prosthetic head in such manner to define an annular step (12), a truncated-conical portion (17) obtained in the internal surface of the body of the prosthetic head starting from said lower edge (19) of the prosthetic head, said truncated-conical portion (17) of the prosthetic head being suitable for being coupled in conical coupling mode with a truncated-conical part (73) of an insert (7) intended to be inserted in the prosthetic head； wherein said projection (11) is shaped as a portion of a spherical cap.
