Which of the following statement(s) is/are true concerning bone remodeling?

b. The remodeling process takes approximately 120 days in an adult

c. Trabecular bone remodeling occurs up to 10 times faster than cortical bone remodeling

d. Bone modeling involves bone formation without resorption

After the initial development and deposition of bone, it is remodeled in an effort to produce a more optimally aligned and constructed structure. This process involves the resorption by osteoclasts followed by deposition of nonmineralized matrix (osteoid) by osteoblasts. During mineralization, the osteoblasts become entrapped in their matrix, thereby serving as the resulting bone cells (osteocytes). This remodeling can occur on the surface of trabeculi, on the surface of cortical bone, and intercortically. It precedes as a method of normal turnover, providing access to minerals needed for normal homeostasis. Under normal circumstances, the process takes about 120 days in an adult. Trabecular bone remodels at a rate 5 to 10 times that of cortical bone remodeling, probably because of its porosity and greater surface/volume ratio.

It is important to differentiate bone remodels from modeling. Bone remodeling involves the resorption of existing bone followed by formation within the resorption cavity. Modeling describes the phenomenon of bone formation without resorption. This modeling can occur only through the deposition of woven bone and occurs during fracture healing.