Osteogenesis only occurs with autograft tissue and allograft cellular bone matrices. A biomaterial may also be an autograft, allograft or xenograft used as a transplant material. Variations on the nerve autograft include the allograft and the xenograft. Other graft options include iliotibial band autograft, hamstrings autograft or quadriceps tendon autograft. This can either be from the person (autograft) or from a donor (allograft). The bone chain can be repaired using autograft of incus or cartilage. Allograft bone is a logical alternative to autograft. The piece of nerve used in this case is called an autograft autotransplantation. Autograft and allograft bone blocks also may be used, but are dependent on the technique.