A medical implant system has parts for detachably establishing a spatial orientation between a body implant such as a bone plate and an aiming device. A contoured portion of a body implant is designed in such a manner that an adapter device can be detachably fastened to the body implant by means of a mechanic form-fit connection. Preferably the form-fitting elements are grooves and protrusions which tightly engage when clamped together. The adaptor device provides a basis for aiming or targeting a device such that the targeting device may be detachably positioned in a stable spatial position with respect to the body implant. Preferably, the adaptor device comprises a dowel pin, a handling device and a clamping element, which elements allow for a quick and easy assembling and disassembling of the adaptor device in a desired alignment.
