1.1. Musculoskeletal Growth Injury and Repair - Bone Growth and Fracture Healing

Question 1

What are the stages of Bone Growth?

Answer 1

1. It starts as a Hyaline Cartilage “Model”
2. This develops a Primary Ossification Center (in the middle of the bone), a Bone Collar, and a Periosteum
3. Secondary Ossification Centers develop (in the ends of the bone), and Blood Vessels enter all of the Ossification Centers
4. A Medullary Cavity forms in the middle of the bone
5. Articular Cartillage covers the Spongy Bone at the ends, an Epiphyseal Plate separates the ends from the Shaft, the Shaft is formed of Compact Bone

Question 2

What is the Shaft of a bone, known as?

Answer 2

The Diaphysis

Question 3

What is the Flare at the End of the Shaft, known as?

Answer 3

The Metphysis

Question 4

What is the Growth Plate, known as?

Answer 4

The Physis

Question 5

What are the Joints on the side of the Physis known as?

Answer 5

The Epiphysis

Question 6

Where is the Medullary Canal found?

Answer 6

It is the Central Cavity of the Bone Canal

Question 7

What is the difference between Cortical and Cancellous Bone?

Answer 7

Cortical:
1. Found in the Diaphysis of the Bone
2. Resists Bending and Torsion
3. Laid down Circumferentially
4. Less Biologically Active
Cancellous:
1. Found in the Metaphysis
2. Resists / Absorbs Compression
3. Is the Site of Longitudinal Growth
4. Is very Biologically Active

Question 8

What is the definition of a “Fracture”?

Answer 8

A break in the continuity of the bone.
It may be a crack, break, split, crumpling, or buckle
Note - “#” is the shorthand for Fracture

Question 9

Why do Bones fail, and Fracture?

Answer 9

1. High Energy Transfer in normal bones
2. Repetitive Stress in normal bones (Stress fracture)
3. Low Energy transfer in abnormal bones

Question 10

Why might bones be abnormal, leading to fractures?

Answer 10

1. Osteoporosis
2. Osteomalacia
3. Metastatic Tumour
4. Other bone disorders

Question 11

What occurs during a “Fracture”?

Answer 11

1. Mechanical and Structural Failure of Bone
2. Disruption of Blood Supply
3. Regenerative Process

Question 12

What are the Stages of the Regenerative Process of Bone?

Answer 12

Stage 1 - Inflammation
Stage 2 - Soft Callus
Stage 3 - Hard Callus
Stage 4 - Bone remodeling

Question 13

When does the Inflammation Stage of Bone Regeneration begin?

Answer 13

Immediately after the Fracture

Question 14

What happens to the products of Cell Death during the Inflammation Stage of Bone Regeneration?

Answer 14

They are dealt with by Lysosomal Enzymes