A disk prosthesis for cervical vertebrae. The prosthesis includes a spherical cap formed on a first insert, while a spherical cup is formed on a second inset, two inserts made of ceramic material, one of the inserts being mounted on a first plate while the other insert is mounted on a second plate in such a manner that the center of rotation of the joint is substantially centered relative to the edges of the plates, a spherical cup possessing a contact surface area that is not less than that of the spherical cap and being connected via an annular molding to the base of the insert, and a plate provided with the insert having the spherical cap includes an annular setback to leave clearance for the annular molding.