AEMCA Practice Exam

What is the primary composition of the bony callus formed during healing?

1. Dense fibrous tissue

2. Compact bone

3. Spongy bone

4. Cartilage

The correct answer is: Spongy bone

The primary composition of the bony callus formed during the healing process is spongy bone. When a fracture occurs, the body initiates a healing response which includes inflammation, followed by the formation of a soft callus made primarily of cartilage and fibrous tissue. As healing progresses, this soft callus is gradually replaced by a bony callus, which is mostly composed of spongy bone. Spongy bone, also known as cancellous bone, has a porous structure that allows for an increase in surface area, facilitating the exchange of nutrients and waste products during the healing process. This is crucial because the healing bone needs to be metabolically active, and spongy bone provides the necessary environment for cellular activities involved in remodeling the fractured area to restore its integrity. Eventually, this spongy bone may be remodeled to become denser and more compact as healing progresses, but the initial bony callus is predominantly spongy bone in structure.