Disc prosthesis device for the cervical spine

A disc prosthesis comprising an insert in the form of a flexible cushion, a first half-shell, a second half-shell, the insert in the form of a flexible cushion being positioned between the half-shells, characterized in that a first of the half-shells comprises a first base provided with a first face for attachment to a first vertebra and with a second face carrying a crown surrounding a first cup, and wherein a second of the half-shells is provided with a first face for attachment to a second vertebra and with a second face carrying a border surrounding a second cup, the cups facing each other and respectively receiving an upper cap and a lower cap of the insert, the crown and the border forming mutually facing inclined walls that fit together with a clearance and producing stops on angular movements and shear movement between the half-shells, the mutually facing inclined walls forming stops both on proximity and inclination of one half-shell with respect to the other half-shell, the half-shells being held spaced apart by the insert during normal physiological stresses on the prosthesis.