MSK #1A - Bone: Normal Structure and Trauma Flashcards
(97 cards)
1
Q
What are the types of bones?
A
Long Bones (Humerus, femur, tibia)
Short Bones (Carpals/Tarsals
Flat Bones (Protective –> Skull)
Irregular Bones (vertebrae, facial bones)
2
Q
What is the diaphysis?
A
Primary ossification center
Body of bone
3
Q
What is the metaphysis?
A
Flattened portion of the diaphysis
4
Q
What is the epiphysis?
A
Secondary ossification center (develop after birth)
5
Q
What is the epiphyseal plate?
A
Cartilagenous growth plate between diaphysis and epiphysis
6
Q
What are the 2 types of bone?
A
Compact (cortical)
Spongy (cancellous, trabecular)
7
Q
How much of the skeleton is made of compact bone?
A
80%
8
Q
What is the turnover rate of compact bone?
A
Slow
9
Q
Describe the organization of compact bone
A
Dense tightly packed osteons w/ haversian canal system
10
Q
What is the Haverisan system?
A
Haversian canal surrounded by lamelle
11
Q
What does the haversian canal contain?
A
Blood vessel and nerve
12
Q
What do the blood vessel and nerve of the haversian canal do?
A
Communicate w/ periosteum
13
Q
What are lamelle?
A
Concentric layers of bone surround haversian canal
14
Q
Where are osteocytes found in the haversian system?
A
W/ in concentric layers
15
Q
What is volkman’s canal?
A
Horizontal canal system connecting to periosteum
16
Q
How much of the skeleton is made of cancellous bone?
A
20%
**less dense but “large” surface area
17
Q
What is the turnover rate of cancellous bone?
A
High turnover rate
**undergoes remodeling according to line of stress
18
Q
What is Wolff’s Law?
A
Increased mechanical stress will increase bone density
19
Q
What is the periostium?
A
Thin, double-layered, tough fibrous membrane that surrounds the bone
20
Q
Where will you find periostium?
A
Surrounds all bone EXCEPT @ ligament or tendon insertion sites
21
Q
What does the outer layer of the periostium contain?
A
Capillaries
Nerves
22
Q
What does the inner layer of the periostium contain?
A
Sharpey’s fibers
If active bone formation –> osteoblasts
If inactive bone formation –> fibroblasts (can become osteoblasts if new growth occurs)
23
Q
What do sharpey’s fibers do?
A
Anchor periostium, tendons, ligaments to cortical bone
24
Q
Where is bone marrow found?
A
In cavities between osseous component of bone
25
What does bone marrow consist of?
Blood vessles
Nerves
Mononuclear Phagocytes
Stem Cells
Blood Cells in various stages of differentiation
Fatty Tissue
26
What is the function of bone marrow?
Formation of blood cells
27
What are the 2 types of marrow in adults?
Red (active)
Ylleow (inactive)
28
Where is active bone marrow found?
```
Trabecular or spongy bone regions of
Pelvis bones
Vertebrae
Cranium
Mandible
Sternum
Ribs
Proximal femur
Humerous
```
29
Where is inactive bone marrow found?
Medullary cavity of long bone
**fatty cells
30
What is the primary source of blood to the bones?
Nutrient arteries
**usually enter middle of diaphysis
31
What are the other arteries that supply bone?
Epiphysiseal/metaphyseal arteries
Periosteal Cappilaries
32
Why is blood supply critical to bones?
Fracture Repair
Maintain Bone Health
33
In healthy remodeling, where do you have bone remodeling?
Both cortical and cancellous bone
34
When does general healthy remodeling occur?
Throughout life
35
In healthy remodeling what is the relationship between osteoblasts and osteoclasts?
Balance between them
36
In osteoporosis what is the relationship between osteoblasts and osteoclasts?
Osteoblast activity < Osteoclast activity
37
What are the phases of bone remodeling?
Activation
Resorption
Reversal
Formation
Quiescence
38
What is the stimulus for activation of bone remodeling?
Hormones
Drugs
Physical Stimulus
39
What happens after bone remodeling is activated?
Resting osteoblasts stimulated to signal activation of osteoclastic activity
40
What is the action of the resorption phase of bone remodeling?
Osteoclasts break down bone --> create resorption cavity
41
What does the resorption cavity follow in compact bone?
Longitudinal axis of haversian's canal
42
What does the resorption cavity follow in canncellous bone?
Surface of trabeculae
43
What happens during the reversal phase of bone remodeling?
Macrophages "clean up" site and prepare it for laying down new bone
44
What is the action of the formation phase of bone remodeling?
Osteoblasts lay down new bone in resorption cavity
45
Explain the formation phase of bone remodeling in compact bone
Bone laid down in concentric layers until small canal is formed (haversian's canal)
46
Describe the formation phase of bone remodeling in cancellous bone
Trabeculae are broken down and new ones are formed
47
What is the quiescence phase of bone remodeling?
Osteoblasts rest and become "bone lining cells" on the newly formed bone surface
48
What is a fracture?
Any defect in the continuity of a bone
49
What are the 3 basic etiological classifications of fractures?
Sudden traumatic fracture --> single episode of excessive force
Stress or fatigue fracture --> repetitive episodes of "normal" force
Pathological fracutre --> "normal" force on abnormal bone
50
How are fractures "described"
Anatomical location of fracture --> name of bone
Region of bone that is fractured --> diaphysis, metaphysis, physis, epiphysis
Direction of the fracture line --> transverse, oblique, spiral
51
What is a comminuted fracture?
Fx w/ 3+ fragments
52
What is a pathological fracture?
Fx in area of pre-existing bone dz
53
What is an incomplete fracture?
Fx doesn't span entire cross section of bone
54
What is a segmental fracture?
Fx middle fragment of bone surrounded by proximal and distal segments
55
What is a butterfly segment fracture?
Similar to segmental fx except fx doesn't span entire cross section of bone
56
What is a stress fracture?
Small fx caused by repetitive loading of bone
57
What is an avulsion fracture?
Portion of bone is separated from bone caused from pulling of tendon or ligament @ insertion site
58
What is a closed fracture?
Fx not exposed to external environment
59
What is an open fracture?
Fx exposed to external environment
60
What is displacement (translation) of a fracture?
Describes the position of DISTAL FRAGMENT --> anterior/posterior, medial/lateral
61
What is rotation of a fracture?
IR/ER w/ observation
62
What is shortening of the fracture?
Ends of the fx overlap
63
What is angulation?
Direction in which the DISTAL FRAGMENT point --> ie lateral/medial angulation
64
What happens to the bone upon the initial fracture?
Periosteum and blood vessels in the cortex and marrow are ruptured
65
What are the 3 phases of bone healing and how long do they last?
Inflammatory (days up to 1 - 2 wks)
Reparative (up to several months)
Remodeling (months to years)
66
Describe the inflammatory phase of bone healing
Increased blood flow into the area after acture response to fracture
Hematoma forms
Osteoclastic activity removes damaged bone
Growth Factors stimulate fibroblasts, osteoblasts @ site
67
What does the x-ray look like during the inflammatory phase?
Fracture line becomes more visable as necrotic tissue is removed
68
What forms during the reparative phase?
Soft fibrous callus forms --> hard callus (immature bone)
69
What is responsible for soft callus mineralizing into the hard callus?
Osteoblasts
70
What does the x-ray look like during the reparative phase?
Fracture line begins to disappear
71
What happens during the remodeling phase?
Immature bone is replaced by organized mature bone
Fracture line disappears
72
What is the criteria that goes into deciding when a fracture is healed?
Clinical judgement (pts pain, etc)
Radiographic apperance (callus formation and disappearance of fx line)
Anatomical location of fracture and device (different bones heal @ different rates)
73
What are the factors that will vary healing time?
Age
Location
Type
Severity
74
What are the clinical signs/symptoms of fractures?
Approriate history --> trauma, pathological, stress fracture
Localized pain
Pain w/ weight bearing
Edema/ecchymosis (bruising)
Loss of function and mobility
75
What are the immobilization devices that promote secondary healing w/ periosteal callus formation?
Cast
Intramedullary rods/nails
Pins/wires/screws
External fixator --> less rigid fixation
76
What type of healing does a compression plate use?
Primary bone healing --> NO periosteal callus formation --> longer healing time
77
What is closed reduction?
Manual manipulation of the extremity to align the fracture fragments (when you broke your pinky)
78
What is open reduction?
Surgical reduction of extremity to align the fracture fragments --> ORIF - open reduction and internal fixation
79
What are some complications that can happen as fractures heal?
Delayed healing or non union --> avascular necrosis (femur head/scaphoid)
Infection
80
What are some potential secondary complication of fractures (5 things)?
Potential growth impairments in kids
Long term disuse can have significant impact on elderly
Cardiopulmonary complications d/t immobilization
Bone - localized osteoporosis
Transient muscle atrophy
81
What are the 5 types of salter harris fractures in developing bone?
Type 1 = disruption of growth plate (distraction or slip injury)
Type 2 = fx line through growth plate and metaphysis
Type 3 = fx line through growth plate and epiphysis
Type 4 = fx through metaphysis, growth plate, epiphysis
Type 5 = compression injury of growth plate
82
What are the 2 types of bone formation?
Intramembranous ossification
Endochondral ossification
83
What types of bone undergo intramembranous growth?
Flat bones: skull, face, mandible, clavicle
84
How does intramembranous growth occur?
W/o cartilage model
85
What is stage 1 of intramembranous ossification?
Undifferentiated mesenchymal cells differentiate into osteoblasts --> bone
86
What is stage 2 of intramembranous ossification?
Osteoblast secretes bony matrix in surrounding fibrous membrane
Matrix --> clacified
Osteoblast = osteocytes "trapped" w/ matrix
87
What is stage 3 of intramembranous ossification?
Formation of trabeculae - obsteoid form around invaginating blood vessels
Periosteum forms from mesenchymel cells
88
What is stage 4 of intramembranous ossification?
Bone collar of compact bone forms
Red marrow is now formed w/ in trabeculae
89
How does endochondral ossification growth occur?
Cartilage model --> bone REPLACES cartilage (cartilage not converted into bone)
90
When does endochondral ossification occur?
Longitudinal bone growth during development
Appositional growth (widening) during early development
91
What are the 2 cartilagenous growth zones that exist in immature long bone?
Spherical zone
Physis (epiphyseal plate)
92
Where is the spherical zone found?
Around the end of the epiphysis (allows for growth of epiphysis)
93
Where is the epiphyseal plate (aka grwoth plate) found?
Between metaphysis and epiphysis (allows for longitudinal growth)
94
What are the 3 layers of the epiphysis?
Reserve Zone (early stages of cartilage cell)
Proliferative Zone (Mature Cartilage Cell)
Hpertrophic Zone (Cartilage cell hypertrophies, accumulate calcium then die --> obsteoblasts enter and form new bone)
95
When do the epiphyseal plates fuse?
14 - 21 years
**earlier in females vs. males (earlier puberty)
96
Which bones are 80% grown by age 8?
Spine
**premature closure of lower extremity growth plates will influence height more than spine
97
During childhood which bones grow faster?
Extremities
