the longitudinal section of an endorposthesis of an intervertebral disc as illustrated in fig1 shows a central raised dome 3 and 4 on each of its frontal areas 1 and 2 bordering the vertebrae . each of the raised domes 3 and 4 are surrounded by roof - shaped projections of which two , as examples , have been designated 5 and 6 . the sloped , upwardly projecting edges of the projections 5 and 6 are in the form of cutting edges which facilitate the pressing of the prosthesis onto the levelly milled vertebrae . because the inside of the vertebrae consist of soft tissue the ridges 6a and 6b of the projections 5 and 6 , which extend further than the raised domes 3 and 4 , can be pressed into the bone tissue . in order to be able to hold and direct the endoprosthesis with a surgical forcep the lateral surface area of the endoprosthesis has a circumferential groove 7 . this groove forms a round depression in cross - section and spans approximately half of the height of the lateral surface area . fig1 a shows an enlarged view of detail ia of the endoprosthesis of fig1 . the surface of the frontal area 1 is coated with a porous biocompatible layer 26 . this surface coating 26 can either be smoothly 26 or roughly structured 26a . the treated and porous surface 27 of frontal area 2 in fig1 b is partially filled with resorbable material 28 in order to enable the ingrowth of bone material . such a surface treatment 27 and / or surface coating 26 serve to facilitate growth onto the bone . fig2 shows a plan view of one of the two similarly shaped frontal areas 1 or 2 of the endoprosthesis . the round frontal area 1 or 2 is subdivided into one central region in which the raised dome 3 or 4 is situated and four ring - shaped regions which surround the raised dome 3 or 4 . twelve roof - shaped projections 5 or 6 are situated in each of the ring - shaped regions and the shape and the size of the projections 5 or 6 are the same in each of the ring - shaped regions . the surface structure of the frontal areas 1 and 2 comprises twelve identical segments . the segments , together with the raised dome 3 or 4 , prevent an unintentional dislocation in any radial direction . the longitudinal base edges 8 and 9 of the ridge 10 of the roof - shaped projections 5 or 6 form concentric arcs of circles whereby the ridge 10 is not as long as the longitudinal base edges 8 and 9 . in that way , the gable end faces 11 of the roof - shaped projections 5 or 6 incline upwardly . the projections are therefore shaped like a hip roof . an unintentional rotation of the intervertebral implants can be prevented in both tangential directions due to these gable end edges . the roof - shaped projections 5 or 6 as arcs of circles are longer with increasing distance from the center . they are symmetrically situated on radii of the round frontal areas and form a ray - like pattern . regions lying on the same level as the frontal areas of the essentially cylindrically shaped endoprosthesis remain in between the projections . a perspective view of the endoprosthesis of the intervetebral disc is illustrated in fig3 as a wire model in order to emphasize the surface structure . a further variation of the intervertebral implant according to the invention is shown in the fig4 a to d . the elements which correspond to those elements of the previously described embodiment are given the corresponding numerals onto which an &# 34 ;&# 39 ;&# 34 ; has been added . in the sectional view of fig4 a it can be seen , that both frontal areas have an inclination of approx . 7 ° relative to each other . the direction of inclination is chosen to be symmetrical to the middle plane for both frontal areas and is therefore approx . 35 ° between the middle plane and each frontal area . the diameter of the implant is between 16 and 20 mm whereas the height is between approx . 6 and 9 mm . the total inclination of the frontal areas is increased with increasing diameter of the embodiments corresponding to different vertebrae sizes so that the greatest inclination corresponds to the greatest diameter and vice versa . in the plan view according to fig4 b a rounded recess 12 can be seen , which has a depth of 10 % of the diameter . the recess is substantially cylindrical , whereby the axis of the rounding runs parallel to the geometrical axis of the implant . the recess prevents the nerve tracts in the spinal region from being blocked by the implant . the radius of the rounding is approximately equal to half the radius of the frontal areas . as can also be seen from fig4 d the recess is on that side of the implant with the smallest distance between both frontal areas . it can be seen from the sectional view according to fig4 a and also from the side view according to fig4 c that the shown implant has a bore 13 which extends beyond the middle region by about half a diameter of the dome 3 &# 39 ; or 4 &# 39 ;. a metrical internal thread 14a is provided between an outer enlarged area 14 and the end of the bore . the outer enlarged area 14 prevents the bone from being able to grow into the threaded bore . in addition , another cap -- not shown in the figure -- made from an elastic biocompatible material , for example silicon rubber , is provided , with which the opening can be closed over after the implant has been inserted . the bore serves to receive an instrument to manipulate an intervertebral implant , the instrument being shown in fig5 a in the plan view in section and in fig5 b in side view . on a slim shaft region 15 a striking weight 16 is displaceable between two stops 17 and 18 so that an insertion or removal of the implant which is connected to such a setting instrument can take place in accordance with the strike direction . the stop 17 is formed by the front end of a casing 19 which is longitudinally displaceable along the shaft 15 by a set distance . the casing 19 has a screw 20 which is firmly connected to the casing 19 and whose end which faces the middle axis of the casing projects into the inside of the casing . this end engages with a region 21 of the shaft 15 having a reduced diameter . in this way , the casing 19 can not be totally removed from the shaft 15 . the casing is oval in cross - section and has projections 22 and 23 on the side opposite the stop 17 which grip into the corresponding recesses of the implant . a free threadless shaft end 24 corresponds in its diameter to the bore 13 and the adjoining external thread 25 corresponds to the internal thread 14a of the bore . to insert the implant the free end of the shaft 24 with the external thread 25 is inserted in the bore of the implant and is firmly screwed in . the noses 22 and 23 are thereby pulled into the circumferential groove of the implant and thereby make it possible for the position of the implant to be controlled by holding the casing 19 . the implant can now be driven in with the set weight 16 . after the final position has been reached the instrument is removed . in order to remove the implant during reoperation the steps must be carried out in the opposite order . it will be understood that the above description of the present invention is susceptible to various modifications , changes and adaptations , and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims .