An intervertebral implant includes a middle part, comprising two pins, which can be introduced into the intervertebral space between two vertebrae having a central axis, a first end intersecting the central axis, and a second end intersecting the central axis, and two longitudinal parts each with a longitudinal axis extending transversely to the central axis of the middle part and each with an apposition surface directed transversely to the central axis of the middle part contacting the two processi spinosi of two adjacent vertebra bodies. Each part is connectable with one end of the middle part in such a manner that the apposition surfaces are directed against one another. The middle part of the implant is extendable transversely to its central axis along the longitudinal axes of the two parts.