Lesson 7: Bone Repair

Question 1

 any break in a bone
 named according to their severity, the shape or position of the fracture line, or even the physician who first described them.

Answer 1

Fracture

Question 2

 series of microscopic fissures in bone that forms without any evidence of injury to
other tissues.
 painful and also result from disease processes that disrupt normal bone calcification

Answer 2

Stress Fracture

Question 3

Phase of Bone Repair;
 early inflammatory phase
 Blood vessels crossing the fracture line are broken.
 As blood leaks from the torn ends of the vessels, a mass of blood (fracture hematoma)
forms around the site of the fracture.
 forms 6 to 8 hours after the injury.

Answer 3

Reactive Phase

Question 4

characterized by two events:
a. the formation of a fibrocartilaginous callus
b. formation of a bony callus to bridge the gap between the broken ends of
the bones.
 Blood vessels grow into the fracture hematoma and phagocytes begin to clean up
dead bone cells.
 Fibroblasts from the periosteum invade the fracture site and produce collagen fiber.

Answer 4

Reparative Phase: Fibrocartilaginous Callus Formation

Question 5

 In areas closer to well-vascularized healthy bone tissue, osteoprogenitor cells develop
into osteoblasts, which begin to produce spongy bone trabeculae. The trabeculae join
living and dead portions of the original bone fragments.
 In time, the fibrocartilage is converted to spongy bone, and the callus is then referred
to as a bony (hard) callus. The bony callus lasts about 3 to 4 months.

Answer 5

Reparative Phase: Bony Callus Formation

Question 6

 The final phase of fracture repair is bone remodeling of the callus.
 Dead portions of the original fragments of broken bone are gradually resorbed by
osteoclasts.
 Compact bone replaces spongy bone around the periphery of the fracture.

Answer 6

Bone Remodelling Phase

Question 7

bone breaks into three or more fragments

Answer 7

Comminuted

Question 8

bone is crushed

Answer 8

Compression

Question 9

broken bone portion is pressed inward

Answer 9

Depressed

Question 10

broken bone ends are forced into each other

Answer 10

Impacted

Question 11

ragged break occurs when excessive twisting forces are applied to a bone

Answer 11

Spiral

Question 12

bone breaks incompletely, much in the way a green twig breaks

Answer 12

Greenstick