Bone Response to Growth, Injury, Overuse, Disuse and Aging

Question 1

Name 2 other roles bone fulfill besides structural support.

Answer 1

hematopoiesis

calcium storage and hemeostasis

Question 2

Name the two types of epiphysis

Answer 2

pressure (weight bearing, longitudinal growth)

traction (attachment of muscles- apophysis)

Question 3

What are the 3 zones of the epiphyseal plate?

Answer 3

reserve
proliferative (optimal blood supply
maturation

Question 4

What is essential for bone remodeling?

Answer 4

requires and active and healthy growth plate

Question 5

Describe injury to the growth plate that can result in permanent injury. (III, IV, V)

Answer 5

III: fracture through growth plate and part of epiphysis breaks off
IV: fracture through growth plate and chunks of metaphysis and epiphysis breaks off
V: crush injury of the growth plate (compression)

physis misalignment and formation of bony bridge can tether bones in ways that prevent elongation

Question 6

What are the possible consequences of growth arrest due to damage of the growth plate?

Answer 6

extremity grows short, crooked or both

Question 7

Name the stages of secondary fracture healing (4 steps).

Answer 7

1. Inflammation
2. soft callus (creates stability)
3. hard callus
4. remodeling

Question 8

How does primary bone healing occur?

Answer 8

artificial stability must be provided by internal fixation- causes bone to go straight to cortical remodeling

Question 9

How would you detect stress fracture with only plain films?

Answer 9

would need to wait approx 3 weeks for secondary bone healing- callus formed over fracture (discernible on X-ray)

Question 10

Why is use/movement/exercise important for bone quality?

Answer 10

skeletal muscle as well as impact form the ground causes it to retain calcium and become stronger (immobility is worse for bone density than calcium deficiency)

Question 11

Match the terms for decrease bone quality, quantity and density.

Answer 11

decreased density: osteopenia
decreased quality: osteomalacia- defective mineralization (in children- Ricketts)
decreased quantity: decreased bone quantity

Question 12

Name the the two main factors that lead to more fractures in the elderly.

Answer 12

decreased bone density
muscle weakness leading to more falls

(add less effective healing/ remodeling you get lots of morbidity)

Question 13

What factors can be encouraged to improve bone health?

Answer 13

assessment of bone mineral density
avoid smoking
adequate Ca and Vit D
pharmacological agents that encourage mineralization
hormonal replacement (estrogen)
impact routine exercise
strength training