Fractures
A fracture is a break in a bone. Fractures can be classified in the following manner:
Simple: Broken bone does not pierce the skin. Compound: Broken ends of bone pierce the skin. Complete: Bone is broken into two parts.
Partial: Bone is broken longitudinally but not separated into two parts.
Greenstick: A break on the outer arc of the bone is incomplete.
Impacted: Broken ends of bone are wedged into each other.
Comminuted: Bone breaks into several fragments. Spiral: Due to twisting of bone, the break is ragged.
Repair of a Fracture
Repair of a fracture entails these steps:
1) Hematoma. Blood escapes from ruptured blood vessels and forms a hematoma (mass of clotted blood) in the space between the broken bones. The area is inflamed and swollen.
2) Fibrocartilage callus. Tissue repair begins, and fibrocartilage now fills the space between the ends of the broken bone. Collagenous fibers tie the ends of the bones together.
3) Bony callus. Osteoblasts produce trabeculae of spongy bone and convert the fibrocartilage callus to a bony callus that joins the broken bones together.
4) Remodeling. Osteoblasts build new compact bone at the periphery, and osteoclasts reabsorb the spongy bone and build a new medullary cavity.
Bone is a living tissue that is always being remodeled. Fractures are of various types. but repair requires four steps: (1) hematoma. (2) fibrocartilage callus. (3) bony callus.
and (4) remodeling.
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