Week 4 - Bone Physiology, Fractures, Healing Flashcards
(49 cards)
1
Q
What are the 4 types of bone cells?
A
- osteocytes
- osteoblasts
- osteoclasts
- osteogenic cells
2
Q
Compact bone
A
- ~80% of bone mass
- dense outer layer
- allows bone to resist bending and otrsion
3
Q
Spongy bone
A
- ~20% of bone mass
- deep to compact bone, mesh-like trabeculae
- allows bone to resist forces in many directions
4
Q
Bone marrow
A
- found in medullary cavity and within spongy bone
- yellow and red marrow
5
Q
Yellow bone marrow
A
- found in long bones of adults
- adipose tissue
6
Q
Red bone marrow
A
- site of hematopoiesis
- cranium, vertebral body, ribs, sternum, ilium, proximal epiphyses of humerus and femur
7
Q
Bone remodeling: formation and reabsorption
A
- balanced activity between osteoclasts and osteoblasts
- modulated by hormones and physical stress
8
Q
What is a fracture
A
a complete or partial break in a bone
9
Q
4 Types of bone fracture classifications
A
- complete or incomplete
- open or closed
- number of fracture lines
- direction of fracture lines
10
Q
Complete bone fracture
A
bone is broken to form 2+ pieces
11
Q
Incomplete bone fracture
A
- bone only partially severed
- more common in children because of softer bone (e.g. greenstick fracture - bending of softer bone)
12
Q
Open (compound) bone fracture
A
- skin is broken
- bone fragments may protrude through skin
- usually more damage to soft tissue surrounding the bone
- higher risk of infection
13
Q
Closed bone fracture
A
- skin not broken through
14
Q
Simple bone fracture
A
- single break
- bone ends maintain alignment and position
15
Q
Comminuted bone fracture
A
multiple fracture lines and bone fragments
16
Q
Compression fracture
A
bone is crushed into smaller pieces and collapses
17
Q
Spiral bone fracture
A
angles around the bone
18
Q
Transverse bone fracture
A
across the bone
19
Q
Oblique bone fracture
A
at an angle with respect to the diaphysis
20
Q
longitudinal (linear) bone fracture
A
along the axis of the bone
21
Q
Impacted bone fracture
A
one end forced into the other at the location of the break
22
Q
Stress fracture
A
repeated excessive stress
23
Q
Pathologic bone fracture
A
- weakness in bone structure due to other conditions
- can cause spontaneous fractures
- e.g. osteoporosis, bone tumor
24
Q
Fracture signs and symptoms
A
- pain, swelling, bruising, altered sensation, inability to move limb or bear weight
- affected area may look misaligned, shortened, deformed
25
Fracture treatments
- immediate immobilization
- surgery if needed
- exercise to maintain range of motion, muscle mass, circulation
26
3 steps to broken bone healing process
1. inflammatory phase
2. reparative phase
3. remodeling phase
27
Bone healing - inflammatory phase
- hematoma & edema
- immune cells recruited
28
bone healing - reparative phase
- granulation tissues -> procallus -> callus
29
Bone healing - remodeling phase
- Callus -> remodeling -> healed bone
30
Bone healing - hematoma formation physiology
- bone breaks
- bleeding from blood vessels in bone and periosteum
- bleeding around bone from soft tissue damage
- clot forms in the medullary cavity, under the periosteum and between bone fragments
- hematoma
31
Bone healing - inflammatory response and granulation tissue physiology
- bone cell necrosis because of halted nutrient delivery
- inflammatory response due to cell damage and presence of debris at the site
- part of hematoma includes fibrin network formation
- growth of granulation tissue (new connective tissue) within the fibrin network
- new capillaries form, phagocytes remove debris and fibroblasts migrate here
32
bone healing - Procallus (fibrocartilage) formation physiology
- fibroblasts and chondroblasts lay down new collagen to produce cartilage matrix
- the two bones become splinted together by a fibrocartilaginous procallus (not strong enough to bear weight but acts as a preliminary bridge repair
33
bone healing - bony callus formation and remodeling physiology
- osteoblasts generate new bone over the fibrocartilage model (procallus)
- procallus is replaced by bone (bony callus)
- during the following months, in response to mechanical stresses on the bone, repaired bone is remodeled by osteoblasts and osteoclasts activity. excessive callus removed and more compact bone laid down
34
How does age affect bone healing timeline?
Kids: 1-2 months
Adults: 2+ months
35
Factors that can impair bone healing
- extent of damage
- systemic factors
- other complications
36
Complications of fractures
- broken ends of bone can damage surrounding structures
- compartment syndrome
- fractures of long bones
- ischemia due to cast compression
- infection
37
Complication of fractures - compartment syndrome
bleeding or edema -> increased pressure inside limb -> impaired blood supply and potential for tissue necrosis
38
Complications of fractures - long bone fractues
potential for release of adipose from fractured area and enters the blood stream (obstruction of blood flow to the lungs and/or brain)
39
Long-term complications of fractures
- healing abnormalities
- mobility complications
- side-effects of long-term immobilization
40
Malunion bone healing
healing with a deformation
41
Delayed union bone healing
requires time to heal
42
Nonunion bone healing
failure to heal
43
Lumbar Lordosis
spine curves inwards at lower back
44
Common risk factor of Lumbar Lordosis
central obesity
45
Kyphosis
'hunchback'; rounded upper back
46
Common risk factor of kyphosis
poor posture
47
Scoliosis
S or C shaped sideways curvature of the spine
48
Common risk factor of scoliosis
genetics
49
Lumbar lordosis and exercise treatment
- results in anterior pelvic tilt
- build strength in hip extensors
- build strength in abdominals
