An intervertebral prosthetic device has a medullary protection shield with a concave shape designed to be adapted to the anatomy of a medullary canal against which the medullary protection shield is able to be positioned, a spherical tough core inside a flexible integral assembly designed for an intervertebral space, and the flexible integral assembly has a truncated parallelepiped shape, wherein a front portion of the truncated parallelepiped shape is higher than a rear portion of the truncated parallelepiped shape, and wherein the rear portion is concave and corresponds to the concave shaped medullary protection shield.
