What is callus formation in relation to bone healing?

Callus formation is a crucial phase in the process of bone healing, wherein new bone tissue is generated at the site of a fracture. When a bone breaks, the body initiates a repair process that begins with the formation of a hematoma, followed by a soft callus made of cartilage, and then transitioning into a hard callus of woven bone. This new bone formation provides structural support and stability to the area, bridging the gap created by the fracture.

During this phase, osteoblasts (bone-forming cells) are activated to synthesize new bone material and gradually replace the soft callus with more mature bone tissue. This transformation is vital for restoring the integrity and function of the bone, enabling it to withstand forces and mechanical load once healing is complete.

The other options do not accurately represent callus formation: degradation of bone tissue refers to the breakdown of bone rather than its repair, cessation of bone growth implies a stopping point rather than an active healing process, and a physical therapy technique does not relate to the biological process of new bone development occurring during healing. Thus, the correct definition of callus formation is indeed centered around the process of new bone formation.