An implantable bone support system including a shelf clip supported on a portion of the perimeter of the skull opening. The shelf clip includes upper and lower body portions. The legs of the lower body portion are positioned such that one leg is engaged with the skull perimeter in a direction away from the skull opening. The opposing leg is positioned into the skull opening to form a portion of a shelf for receiving the bone flap or implant. In an adjustable height embodiment, the ratcheting leg of the upper body portion engages a central post, via ratchet teeth on the leg and the central post, and is pressed into engagement to capture the skull between the upper and lower body portions. The removable or locking leg is formed for engagement with the upper body portion of the clip, and engages an external surface of the bone flap or implant to capture the bone flap or implant within the shelf created by the clips within the skull opening.