In bone healing, which cells invade the damaged area between the edges of broken bone and lay down fibrocartilage?

In bone healing, which cells invade the damaged area between the edges of broken bone and lay down fibrocartilage?

• A. Fibroblasts
• B. Osteoblasts
• C. Chondrocytes
• D. Osteoclasts

Answer: (A)

In fracture healing, the first bridging tissue that forms in the gap is a soft callus made up of fibrocartilage. This tissue results from cells that invade the fracture site from the surrounding periosteum and connective tissue. The cells that drive this early repair are fibroblasts, which proliferate and synthesize the extracellular matrix, creating fibrous tissue that blends with cartilage to form fibrocartilage within the gap. This fibrous-cartilaginous scaffold stabilizes the fracture before bone formation resumes through endochondral ossification. Osteoblasts would later lay down bone as healing progresses, osteoclasts resorb old or damaged bone, and chondrocytes would contribute to cartilage formation, but the initial invasion that establishes the fibrocartilaginous soft callus is driven by fibroblasts.

In fracture healing, the first bridging tissue that forms in the gap is a soft callus made up of fibrocartilage. This tissue results from cells that invade the fracture site from the surrounding periosteum and connective tissue. The cells that drive this early repair are fibroblasts, which proliferate and synthesize the extracellular matrix, creating fibrous tissue that blends with cartilage to form fibrocartilage within the gap. This fibrous-cartilaginous scaffold stabilizes the fracture before bone formation resumes through endochondral ossification. Osteoblasts would later lay down bone as healing progresses, osteoclasts resorb old or damaged bone, and chondrocytes would contribute to cartilage formation, but the initial invasion that establishes the fibrocartilaginous soft callus is driven by fibroblasts.