Biomechanical Properties and Behaviors of Bone Flashcards Preview

DPT Biomechanics > Biomechanical Properties and Behaviors of Bone > Flashcards

Flashcards in Biomechanical Properties and Behaviors of Bone Deck (68):
1

which bone can absorb a lot of energy (shock absorbing), more flexible

cancellous bone (trabecular, spongy)

2

What kind of force is cortical bone strongest in?

compression

3

which bone fails at low deformation

cortical bone

4

When is cortical bone weakest

shear

5

Which bone can sustain large deformation

cancellous

6

debonding of cement lines, microfracture

tension

7

cracking of osteons

compression

8

how do muscles attenuate tensile stress?

they produce counteractive compressive stress

9

muscle fatigue can lead to a _____ fracture

transverse

10

resorption of older bone and formation of new bone

remodeling

11

_____ of the body's trabecular bone is remodeled each year

25%

12

younger bone is more ductile or brittle

ductile

13

higher loading speed results in more _____ behavior

brittle

14

regarding bending, stresses are higher ______ from the neutral axis

further

15

Where will the structure break in a 3 point bend

point of application

16

Where does the fracture begin in a 3 point bend

on the tensile side (weaker in tension than compression)

17

Where will the structure break in a 4 point bend?

weakest point

18

an oblique fracture will occur when there is _____ compression and _____ failure

high, slow

19

stiffness and load to failure increase with

loading rate (30% stronger during brisk walk than slow walk

20

comminuted or multiple fragment fracture usually occurs in what kind of an environment

high energy

21

with low repetitive forces, osteoclast activity ______ osteoblast activity, leaving no time for body to repair microdamage

outpaces

22

Bone responds to mechanical stresses by increasing/decreasing mass according to magnitudes and directions of forces that are applied

Wolff's law

23

formation of new bone without resorption

modeling

24

resorption of older bone and formation of new bone (osteoclasts and osteoblasts)

remodeling

25

what contributes to bone hypertrophy or increase of mass

osteoblast

26

What are the three parts of the female athlete triad?

eating disorders, amenorrhea, osteoporosis
affects 1-10% of all adolescent and college age women

27

mineralization peaks at what ages for women and men respectively

25-28
30-35

28

What does higher mineralization (larger crystals) mean for older adults?

decreased plastic deformation and energy absorption
increased brittleness

29

side effects of osteoporosis drugs

decreased toughness, increased microdamage accumulation

30

Three most common fracture sites in the aging individual

femoral neck
radius/ulna
spine

31

Which bone can transmit a lot of force, very strong in compression, and very stiff(does not deform much before fracturing)

cortical

32

cancellous bone is able to deform a lot before it fractures. this is primarily due to its

high collagen content

33

During isometric contractions the internal moment is ____ to the external moment

equal

34

During concentric contractions the internal moment is ____ than the external moment

greater

35

During eccentric contractions, internal moment is ____ than external moment

less

36

in the biomechanical muscle model, the sarcomere and passive components (endo-, peri-, and epimysium)

are parallel

37

The maximum torque generated by the hip abductors occurs when the muscles are in a ____ position which corresponds to the functional task of _____

lengthened, single leg stance phase of gait

38

An important function of the acetabular labrum is

it deepens the acetabular cup for increased stability

39

The right lower extremity posture that would be observed in a person who has a dramatic retroversion of the right hip? Anteversion?

duck foot, pigeon toe

40

The right lower extremity position that would be observed in a person who has a dramatic coxa vara of the right hip would be

right genu valgum (knock kneed)

41

a newborn has increased

coxa valga (150 degrees)

42

T or F During 2-legged stance, the hip muscles are primarily responsible for stability of the coxafemoral joint

F - NO muscle activity is required to maintain upright, neutral posture at the hip, ligaments and joint capsule provide stability

43

3 primary functions of the hip

1 support HAT
2 static erect postures
3 dynamic postures

44

What is the loose (open) pack position of the hip

35 degrees flexion/abduction, slight external rotation

45

What is the closed packed position of the hip

maximum extension/int rot/abduction

46

What are the two articulating surfaces of the hip

acetabulum of Os Coxae and head of Femur

47

Which ligament of the hip is known as the Y

iliofemoral (anterior)
the others are pubofemoral (ant/inf)
ischiofemoral (post)

48

a ring of fibrocartilage that encircles the acetabulum and its functions include shock absorption and pressure distribution; joint lubrication; enhances joint stability

acetabular labrum

49

which portions of the acetabular labrum is most innervated

anterior and superior

50

what finishes the acetabular labrum

transverse acetabular ligament

51

What structure deepens the acetabulum by 20 or more percent

acetabular labrum

52

Where is the articular cartilage thickest for femoral head and acetabulum

superiorly

53

What is the only part of the femoral head that is not covered in articular cartilage?

fovea (attachment of the ligamentum teres)

54

What happens if there is a disruptions of the ligamentum teres?

avascular necrosis

55

Angle of inclination in
Infants
adults
elderly

150
125
120

56

females can have a greater pelvic width, which will do what to their angle of inclination?

lessen it

57

when angle is greater than 125, it is called
when it is less than 125, it is called

coxa valga
coxa vara

58

coxa valga corresponds with genu....
coxa vara corresponds with genu....

vara - bowleg
valga - knock-kneed

59

The typical angle of torsion for adults is _____ degrees

12

60

Anteversion causes _____ rotation of the femur when the angle of torsion is ______

internal
greater than 12 degrees

61

Retroversion causes _____ rotation of the femur when the angle of torsion is

external, less than 12 degrees

62

forces in the hip are transmitted to the femoral shaft through the femoral neck. this is what kind of system

cantilever

63

accordion-like folds are found on the inferior and superior aspects of the joint capsule. these are called

frenula (synovial folds)

64

What do the frenula permit

full abduction and adduction range of motion

65

Why do humans have extremely limited hip hyperextension

the three dense and strong ligaments wrap around the hip joint capsule in a clockwise direction

66

T or F The ligamentum teres supports the hip joint

F, its primary purpose is to serve as a guid for oburator artery branch traveling to fovea on head of femur

67

What are the primary muscles involved in unilateral stance

hip abductors, opposite lumbar erector spinae

68

What happens to the right femur if you can see Trendelenburg Sign in right unilateral stance?
pelvis?
lumbar spine?

adducts
left lateral tilt
right lateral flexion