Final answer:
After a fracture, the internal callus is formed immediately to help stabilize the fracture.
Step-by-step explanation:
After a fracture, the internal callus is formed immediately. Within about 48 hours of the fracture, chondrocytes from the endosteum create an internal callus by secreting a fibrocartilaginous matrix between the two ends of the broken bone The internal callus helps stabilize the fracture.