Final answer:
The second step of the fracture and healing process is the formation of internal and external calli, which stabilize the fracture.
Step-by-step explanation:
The second step of the fracture and healing process is the formation of internal and external calli. Within about 48 hours after the fracture, chondrocytes from the endosteum secrete a fibrocartilaginous matrix between the two ends of the broken bone, creating an internal callus. At the same time, periosteal chondrocytes and osteoblasts create an external callus of hyaline cartilage and bone around the outside of the break. This stabilizes the fracture.