Sacrum bodies are seen to be united at their circumferences by bone, wide intervals being left centrally, which, in the fresh state, are filled by the intervertebral discs. The dorsal surface of the sacrum is convex and narrower than the pelvic surface. In the middle line is the median sacral crest, surmounted by three or four tubercles—the rudimentary spinous processes of the upper three or four sacral vertebrae. On either side of the median sacral crest is a shallow sacral groove, which gives origin to the multifidus muscle. The floor of the groove is formed by the united laminae of the
Artificial bone fractured bone. However, if damage to bone is caused by a disease or severe injury, it becomes difficult for the body to repair itself. When the human body is unable to regenerate the lost bone tissue, surgeons come in and replace the missing bone using autografts, allografts, and synthetic grafts (artificial bone). When compare artificial bone to autograft and allograft, it is less invasive and more biocompatible since it avoids the risk of unknown viral infections. When designing implanted biomaterials, key criteria are biocompatibility, osteoconductivity, high porosity and biomechanics compatibility. Artificial bone was initially made of materials like metals and