Non-stable conditions are then followed by an indirect healing process, which produces callus formation. The phases of fracture healing are inflammation, soft callus, hard callus and remodeling.

(A''-D'') As indicted by Safranin O staining (pink-to-red colors), as the healing process progresses the soft callus is increasingly composed of cartilage. Scale bar, 200 mm.

This type of healing of the skull bone is fundamentally different from the healing of a femur fracture. "A broken femur heals by first forming a soft callus, a cartilage cuff, around the fracture site ...

Reparative phase is characterized by the formation of a soft callus, which eventually transitions into a hard callus. Within a few days to weeks after the fracture, fibroblasts, chondroblasts, and ...