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Flashcards in MSK Mod 1 Deck (93):
1

describe short bones
examples of short bones

tend to be equal in both dimension - cuboidal shape
carpals of wrist, tarsals of foot

2

function of flat bones and example

protective
skull

3

examples of irregular bones

vertebrae, facial bones

4

characteristics of long bone

1. diaphysis
2. metaphysis
3. epiphysis
4. epiphyseal plate

5

what is the diaphysis

primary ossification center
body of bone

6

what is the metaphysis

flattened portion of the diaphysis

7

what is the epiphysis

secondary ossification center (develop after birth)

8

what is the epiphyseal plate

cartilagenous growth plate bw diaphysis and epiphysis

9

two types of bone tissue

compact (cortical)
and spongey (cancellous, trabecular)

10

cortical bone
how much of skeleton does it make up
turn over rate

forms 80% of human skeleton
slow turn over rate
dense, tightly pack osteons with Haversian canal system

11

what is the haversian system

1. haversian canal - each canal contains blood vessel and nerve that communicate with periosteum
2. concentric layers of bone surround the canal - lamelle
3. osteocytes found within concentric layers

12

what is the canal system connecting to periosteum

Volkman's canal - horizontal canal system

13

cancellous bone

20% of skeletal mass
less dense but large surface area
higher turnover rate
undergoes remodeling according to line of stress

14

what is Wolff's law

increased mechanical stress will increase bone density

(applies to cancellous bone)

15

what is periosteum

thin, double layered, tough fibrous membrane that surrounds the bone
surrounds all of bone except at ligament or tendon insertion sites
-difficult to separate the periosteum from the bone

16

2 layers of periosteum

1. outer
2. inner

17

what does the outer layer of periosteum contain

contains capillaries and nerves

18

what does inner layer of periosteum contain

-Sharpey's fibers anchor periosteum (as well as tendons and ligaments) to the cortical bone

19

if there is active bone formation then the inner layer of periosteum contains

osteoblasts

20

if there is inactive bone formation then the inner layer contains

fibroblasts that can become osteoblasts if new growth is needed

21

what is the bone marrow

confined to cavities bw osseous component of bone
aka myeloid tissue

22

bone marrow consists of

blood vessels
nerves
mononuclear phagocytes
stem cells
blood cells in various stages of differentiation
fatty tissue

23

function of bone marrow

formation of blood cells

24

two types of marrow in adults

1. red
2. yellow

25

what is red bone marrow

active marrow
not all bones have active marrow
-pelvic bones, vertebrae, cranium and mandible, sternum and ribs, proximal femur, and humerus
-found in trabecular or spongy bone regions

26

what is yellow bone marrow

inactive marrow
yellow represents more of fatty cells
found in medullary cavity of long bone

27

3 examples of blood supply to bone

1. nutrient arteries
2. epiphyseal and metaphyseal arteries
3. periosteal capillaries

28

what is the primary source of blood to the bone

nutrient arteries - enter middle of diaphysis

29

blood supply to the bone is critical for what

fracture repair and to maintain bone health

30

general healthy remodeling occurs in both

cortical and cancellous bone

31

bone remodeling happens when in life

throughout life

32

osteoporosis and relationship of osteoblast activity vs osteoclast acitivity

osteoblast activity

33

phases of bone remodeling

1. activation
2. resorption
3. reversal
4. formation
5. quiescence

34

activation phase of bone remodeling

stimulus - hormone, drug, physical stimulus
action - stimulus activate resting osteoblasts to signal activation of osteoclastic activity

35

resorption phase of bone remodeling

action - osteoclasts break down bone, create a resorption cavity
1. compact bone - resorption cavity follows longitudinal axis of Haversian's canals
2. cancellous bone - resorption cavity follow surface of trabeculae

36

reversal phase of bone remodeling

action - macrophages clean up the site and prepare it for laying down new bone

37

formation phase of bone remodeling-action

action - osteoblasts lay down new bone in resorption cavity

38

formation phase of bone remodeling - compact bone vs cancellous bone

compact bone - bone is laid down in concentric layers until small canal is formed (haversian's canal); Haversian systems are constantly broken down with new ones being formed

cancellous bone - trabeculae are broken down and new ones formed

39

quiescence phase of bone remodeling

action - osteoblasts rest and are now bone lining cells on the newly formed bone surface

40

define a bone fracture

any defect in the continuity of a bone

41

3 basic etiological classifications of fractures

1. sudden traumatic fracture - single episode of excessive force
2. stress or fatigue fracture - repetitive episodes of normal force
3. pathological fracture - normal force on abnormal bone

42

fracture classifications (3 parts)

1. anatomical location of fracture (name the bone)
2. region of the bone (diaphysis, metaphysis, physis, epiphysis)
3. direction of fracture line (transverse, oblique, spiral)

43

define comminuted fx

fx with 3 or more fragments

44

pathological fracture

fx in area of preexisting bone dz

45

define incomplete fx

fx does not span entire cross section of bone, bone is not broken into separate segments

46

define segmental fx

fx middle fragment of bone surround by proximal and distal segements

47

define butterfly segment fx

similar to segmental except fx doesn't span the entire cross section of bone

48

define stress fx

small fx caused by repetitive loading of bone

49

define avulsion fx

portion of bone is separated from bone caused from pulling of tendon or ligament at the insertion site

50

what is a closed fx

fx not exposed to the external environment

51

what is an open fx

fx exposed to the external environment

52

deformities of fx - displacement

aka translation
describes the position of the distal fragment (ant/post, medial/lateral)

53

deformities of fx - rotation

IR/ER with observation

54

deformities of fx - shortening of fx

ends of fx overlap

55

deformities of fx - angulation

direction in which the distal fragment points
ex. lateral/medial angulation

56

bone healing with inital fx

periosteum and blood vessels in the cortex and marrow are ruptured

57

3 phases of bone healing

1. inflammatory phase
2. reparative phase
3. remodeling phase

58

inflammatory phase of bone healing
-what happens during
-xray shows?

increased blood flow into area after acute response to fx
hematoma forms
osteoclastic activity removes damaged bone
growth factors stimulate fibroblasts, osteoblasts at site
xray - fx line becomes more visible as necrotic tissue is removed

59

reparative phase of bone healing
-whats happening?
-xray shows?

soft fibrous callus forms initially followed by a hard callus
-osteoblasts are responsible for mineralized soft callus causing hard callus to form
-hard callus is considered immature bone - stable compared to soft callus but weak compared to mature bone
-xray - fx line begins to disappear

60

remodeling phase of bone healing

immature bone is replaced by organized mature bone
fracture line disappears
process begins during reparative phase

61

length of inflammatory phase of bone healing

days up to 1-2 weeks

62

length of reparative phase of bone healing

up to several months

63

length of remodeling phase of bone healing

months to years

64

goals of fx management

1. achieve anatomic reduction
2. restore stability
3. create environment conducive to fx healing
4. return pt to pre-injury function
5. achieve acceptable cosmesis

65

criteria to determine when a fracture has healed

1. clinical judgement - pt's pain
2. radiographic appearance - callus formation with disappearance of fx line
3. anatomical location of fx and device - different bones heal at different rates
-ex. distal radial fx approx 6-8weeks vs mid diaphyseal fx approx 3 months

66

avg healing time bw:
kids
adolescents
adults

kids - 4-6 weeks
adolescents - 4-8 weeks
adults - 10-18 weeks

67

clinical s/s of fx

1. trauma, pathological, stress fractures
2. localized pain
3. general rule of thumb - focused portion of bone regardless of direction of palpation
4. pain with wt bearing
5. edema, ecchymosis
6. loss of function and mobility

68

examples of long bones

humerus, femur, tibia

69

examples of how to immobilize a fracture

1. cast
2. intramedullary rods/nails
3. pins,wire,screws
4. compression plates
5. external fixator
6. closed reduction
7. open reduction

70

how does a cast help immobilize a fx

secondary healing with periosteal callus formation

71

how does intramedullary rods/nails immobilize fx

secondary healing with periosteal callus formation

72

how does pins, wire, screws immobilize fx

secodnary healing with periosteal callus formation

73

how does compression plate immobilize fx

primary bone healing, NO periosteal callus formation
-slower thus longer period of non-wt bearing

74

how does external fixator immobilize fx

either primary or secondary healing will occur
-if less rigid fixation: callus formation, secondary healing
-if very rigid: no callus formation, primary bone healing

75

how does closed reduction immobilize fx

manual manipulation of the extremity to align the fx fragments

76

how does open reduction immobilize fx

surgical reduction of extremity to align the fx fragments
-ex. ORIF - open reduction and internal fixation

77

healing complications of fx's

1. delayed or non-union
2. avascular necrosis - femur head & scaphoid are common examples
3. infection

78

potential secondary complications of fx's

1. potential growth impairments in children
2. long term disuse can have significant impact on elderly
3. cardiopulmonary complications d/t immobilization
4. bone - localized osteoporosis
5. transient muscle atrophy

79

what are pediatric fx called?

Salter Harris Fractures

80

5 types of Salter Harris Fx's

Type 1: disruption of growth plate - distraction or slip injury
Type 2: fx line thru growth plate and metaphysis
Type 3: fx line thru growth plate and epiphysis
Type 4: fx thru metaphysis, growth plate, epiphysis
Type 5: compression injury of the growth plate

81

two types of bone formation

1. intramembranous ossification
2. endochondral ossification

82

what is intramembranous bone growth

formation of flat bones; occurs in skull, face, mandible and clavicle

83

intramembranous growth pathophys

-occurs without a cartilage model
-undifferentiated mesenchymal cells differentiate into osteoblasts which then form the bone

84

stage one and two of intramembranous ossification

1. cluster of osteoblasts form ossification center within fibrous connective tissue membrane
2. osteoblast secretes bony matrix in surrounding fibrous membrane
-matrix is then calcified - osteoblast are now osteocytes trapped within matrix

85

stage three and four of intramembranous ossification

3. formation of trabeculae - osteoid from around invaginating blood vessels; periosteum forms from mesenchymal cells
4. bone collar of compact bone forms; red marrow is now formed within trabeculae

86

what is endochondral ossification

-has a cartilage model
-bone replaces cartilage (cartilage NOT converted to bone)

87

endochondral ossification is responsible for

1. longitudinal bone growth during development
2. appositional growth (widening)during early development

88

what 2 cartilagenous growth zones exists in immature long bone

1. spherical zone - around the end of epiphysis, allows for growth of epiphysis
2. physis (epiphyseal plate) - between metaphysis and epiphysis; referred to as growth plate; allows for longitudinal growth

89

3 layers of physis

1. reserve zone - early stages of cartilage cell
2. proliferative zone - mature cartilage cell
3. hypertrophic zone - cartilage cell hypertrophies, accumulate calcium and then dies; osteoblasts then enter and form new bone

90

epiphyseal plates typically fuse when?

bw 14-21 yo

91

epiphyseal plates fuse earlier in males or females?

females - d/t earlier puberty of females

92

how much of your spine is formed by the age of 8

80%

93

extremities grow at a __________ rate than axial skeletal throughout childhood

faster
-premature closure of lower extremity growth plates will influence ht more than spine