Final answer:
A comminuted fracture is a type of bone fracture where the bone is splintered, crushed, or broken into pieces at the site of impact, with smaller bone fragments between the main segments. Healing involves the formation of a hematoma, growth of capillaries, and the involvement of fibroblasts and osteoblasts. Complete healing occurs when the internal and external calli unite and the bone is remodeled.
Step-by-step explanation:
A bone fracture that is splintered, crushed, or broken into pieces at the site of impact, with smaller bone fragments lying between the two main fragments, is known as a comminuted fracture. This type of fracture occurs when there are multiple breaks in the bone, resulting in many small pieces between two large bone segments. It can happen due to direct impact, a twisting motion, or compression.
Healing of comminuted fractures begins with the formation of a hematoma, followed by the growth of capillaries and the involvement of phagocytic cells. Fibroblasts produce collagen fibers to connect the broken bone ends, and osteoblasts start to form spongy bone. Eventually, the internal and external calli unite, and the bone is remodeled for complete healing.