A bone fissure is actually a type of bone fracture, which refers to the presence of a crack in the cortical bone, but the stability of the bone remains. Bone fissures also require immobilization and rest to promote healing of the fracture. Generally, healing of a bone fissure takes about 8-12 weeks. However, this can vary based on the specific location of the fracture, the blood supply to the fracture site, and the presence of injuries to other areas, among other factors. Therefore, the typical rest period for a bone fissure is about three months.