Joint Tissues

Question 1

What does tissue function depend on?

Answer 1

cell structure and function - determined by extracellular components

Question 2

What is the study of how different materials and structures are able to provide support in response to changing forces?

Answer 2

mechanical behavior of tissue (deals with relationship between stress and strain)

Question 3

What is the resistance of a material to deformation?

Answer 3

stress

Question 4

What is stress “formula”?

Answer 4

force/unit area

Question 5

What is the deformation that occurs in a material in response to the application of an external load quantified as a percentage of change?

Answer 5

strain

Question 6

What are isotropic materials?

Answer 6

homogenous, exhibit uniform properties when loaded in different directions

Question 7

What are anisotropic materials?

Answer 7

heterogenous, exhibit non-uniform properties when loaded in different directions

Question 8

What is the application of a force, moment, or combination of them to a material?

Answer 8

load

Question 9

What force is equal and opposite loads applied away from the surface of a structure?

Answer 9

tension

Question 10

What does tension result in?

Answer 10

lengthening and narrowing of structure and causes tensile stresses to occur

Question 11

What force is equal and opposite loads applied toward the surface of a structure?

Answer 11

compression

Question 12

What does compression result in?

Answer 12

shortening and widening and causes compression stress

Question 13

What force is opposing loads applied parallel to the surface of a structure?

Answer 13

shear

Question 14

What does shear result in?

Answer 14

internal angular deformation and leads to shear stress

Question 15

What force is opposing loads are applied to the surface of a structure resulting in twisting about an internal axis?

Answer 15

torsion

Question 16

What does torsion result in?

Answer 16

compression and tension and shear stresses

Question 17

What is bending?

Answer 17

three or more loads applied to a structure causing it to bend about an axis external to itself

Question 18

What is combined stress?

Answer 18

combination or two or more loading modes applied to a structure at the same time

Question 19

What is deformation?

Answer 19

change occurring in some dimension of the material in response to an applied load

Question 20

What region of the load-deformation curve signifies the removal of slack within a structure as tensile load is applied?

Answer 20

toe region

Question 21

What region of the load-deformation curve signifies the range in which stress is directly proportional to strain but all the deformation will return to normal after load removal?

Answer 21

elastic range

Question 22

What part of the load-deformation curve signifies the end of the elastic region when load goes to permanent deformation?

Answer 22

elastic limit/yield point

Question 23

What region of the load-deformation curve is the range in which deformation occurs at a rate disproportional to stress and permanent structure remains intact?

Answer 23

plastic region

Question 24

What is the point of the load-deformation curve in which continued load and max load is reached and deformation continues until failure?

Answer 24

ultimate failure point

Question 25

What region of the load-deformation curve does the removal of crimp occur?

Answer 25

toe region

Question 26

What effect does increasing fiber quantity have on response to load?

Answer 26

increases strength, stiffness, and elongation to failure is the same - can resist more load

Question 27

What effect does increasing fiber length have on response to load?

Answer 27

increases elongation to failure, strength remains, stiffness decreases

Question 28

What is Young's modulus?

Answer 28

linear portion of the curve in the elastic region measuring the stiffness/resistance to the external loads (inverse = compliance)

Question 29

If the slope is steep and modulus is high, material exhibits _ stiffness and _ compliance.

Answer 29

high, low

Question 30

Name an example of high stiffness, low compliance in the body.

Answer 30

cortical bone

Question 31

If the slope is gradudal and modulus is low, material exhibits _ stiffness, _ compliance.

Answer 31

low, high

Question 32

Name an example of low stiffness, high compliance in the body.

Answer 32

adipose tissue

Question 33

What is the stress-strain curve?

Answer 33

load-deformation curve in which load is expressed as load per unit area and strain is expressed as deformation per unit of length or percentage of deformation

Question 34

The following characteristics explains what region of the stress-strain curve for collagenous materials? very little force to deform tissue in straightening crimp, tests for ligament integrity when performed on non-injured ligaments, slack taken up in tendon by its attached muscle before force is transmitted to bone

Answer 34

toe region

Question 35

The following characteristics explains what region of the stress-strain curve for collagenous materials? Collagen fibrils are being stretched and are resisting applied force reflects the type of collagen, fibril size, and cross-linking among collagen molecules when the load is removed, structure will return to its pre-stressed dimensions (will take time) includes stress and strains that occur within normal activities typically extends to about 4% strain

Answer 35

elastic region

Question 36

The following characteristics explains what region of the stress-strain curve for collagenous materials? failure of collagen fibers begins, structure no longer capable of returning to OG length after force is removed recovery requires considerable time - healing

Answer 36

plastic region

Question 37

What are clinical examples of plastic region injuries?

Answer 37

Grade I and II ligament sprains/tendon strains

Question 38

The following characteristics explains what region of the stress-strain curve for collagenous materials? remaining collagen fibrils experience increased stress and rapidly rupture sequentially creates overt failure of the tissue

Answer 38

beyond ultimate failure point

Question 39

Failure through the middle of a ligament or tendon is called what?

Answer 39

rupture

Question 40

Failure at bony attachment of a ligament or tendon is called what?

Answer 40

avulsion

Question 41

Failure within bony tissue is called what?

Answer 41

fracture

Question 42

Deformation prior to failure depends on what things?

Answer 42

tissue type and size

Question 43

What is the ability of a material to resist flow and dampen shear forces?

Answer 43

viscosity

Question 44

What is the ability of a material to return to its OG shape following deformation?

Answer 44

elasticity

Question 45

What are the time-dependent properties?

Answer 45

creep, hysteresis, stress-relaxation

Question 46

What is creep?

Answer 46

progressive strain or deformation of a structure under the influence of a constant stress/load

Question 47

True/False: For creep, Force remains constant while length changes.

Answer 47

true

Question 48

What might creep be applied to in the clinical setting?

Answer 48

stretching a shortened tissue - constant force applies and tissue gradually elongates

Question 49

What is stress-relaxation?

Answer 49

decrease in stress within a structure in the presence of a constant strain

Question 50

What does stress-relaxation look like in clinical setting?

Answer 50

therapist may perceived this as a reduced resistance to stretch ex: prolonged static splinting

Question 51

What is hysteresis?

Answer 51

lag of an effect when forces acting upon a material are changes (energy lost as heaT)

Question 52

What are the determinant properties of fibrous connective tissue?

Answer 52

size and density of the structure, mechanical properties and proportion of collagen and elastin, orientation of fibers in the tissue

Question 53

Which of the following is not a mechanical property of fibrous connective tissue? a. high tensile strength b. anisotropic c. stiffness changes with changes in speed of loading d. have significant viscoelastic characteristics

Answer 53

c - stiffness does not change

Question 54

Fails at strains occurs as low as 9% for stuctures with _ elastin fiber content.

Answer 54

little/no

Question 55

Fails at strains occur up to 70% for structures with _ elastin content.

Answer 55

high

Question 56

True/False: Ultimate load and strain increase with increasing speed of loading.

Answer 56

true

Question 57

True/False: Aging results in general loss of collagen content, but increase in collagen cross-linking.

Answer 57

true

Question 58

True/False: The use of NSAIDs can cause a decrease in the tensile strength of CTs due to a decrease in collagen content and in the proportion of non-soluble collagen.

Answer 58

false - increase

Question 59

What are the mechanical determinant properties of cartilage?

Answer 59

``` type (e.g. hyaline), structural composition (i.e. Type I vs II), proportions of structural components (i.e. eater, collagen, elastin, proteoglycans) ```

Question 60

Which of the following is not true for cartilage? a. anisotropic b. biphasic c. capable of large visoelastic deformation d. injury/pain is felt immediately

Answer 60

d - injury can often occur without initial awareness and can progress until tissue destruction is quite advanced before pain is experienced

Question 61

What are the mechanical determinant properties of bone?

Answer 61

size, density, and geometry; mode of loading applied; rate and frequency of loading

Question 62

What are the mechanical properties of cortical bone?

Answer 62

very high ultimate strength in compression and tension, very high stiffness, Fx's @ ~2% strain, stiffness and ultimate load increase with increased speed of loading

Question 63

What are the mechanical properties of cancellous bone?

Answer 63

mod to low ultimate strength depending on porosity, moderate to low stiffness, anisotropic, Fx's @ ~ 7% strain but can sustain as high as 75% before failure in some instances, stiffness and ultimate load tolerance increase with increased speed of loading

Question 64

True/False: Changes in the mech. properties of bone generally parallel changes in bone mass.

Answer 64

true

Question 65

Where are the stresses on bone from?

Answer 65

WBing and muscle loading

Question 66

What type of tension does a dynamic splint provide?

Answer 66

spring-loaded = aids in restoration of knee ext

Question 67

What occurs during static progressive splinting?

Answer 67

apply torque as close to EoR as possible, stress-relaxation, force required to maintain decreases over tine and then adjust to new setting to progress

Question 68

What are some clinical scenarios to utilize open chain exercise?

Answer 68

OA, NWBing, ligament tear, cartilage

Question 69

What are some clinical scenarios to utilize closed chain exercise?

Answer 69

strength, function, bone remodeling (compression), motor unit activity (= increased muscle effort around a joint)

Question 70

Delayed onset muscle soreness is due to what phase of contraction?

Answer 70

eccentric