Exam 1 - Tissue Mechanics

Question 1

local shape change under the effect of applied forces

Answer 1

deformation

Question 2

when a structure is stretched longitudinally

Answer 2

tension

Question 3

What bears tensile loads

Answer 3

annular fibers

Question 4

Tensile forces occur in the IVD during _______ movements

Answer 4

rotational

Question 5

mechanical failure that occurs first in the cartilaginous endplate = ?

Answer 5

nuclear herniation (Schmorl’s node)

Question 6

Compressive loads in extension are transmitted through the facets, leading to _______ injuries

Answer 6

capsular

Question 7

Compressive loads applied with torque around the long axis (rotation) can produce _______ tears in the annular fibers of the IVD.

Answer 7

circumferential

Question 8

Compression + rotation = _______ _______

Answer 8

annular tear

Question 9

_______ is a combination of compression and tension

Answer 9

bending

Question 10

Fractures to long bones frequently occur due to _______

Answer 10

bending

Question 11

Loads applied parallel to the surface of the structure will cause the structure to deform internally in an angular manner

Answer 11

shear

Question 12

_______ bones are most at risk for fractures due to shear

Answer 12

cancellous

Question 13

In the spine, the facet joints and the fibers of the annulus fibrosus _______ shear forces

Answer 13

resist

Question 14

The _______ provides the MAJORITY of the torsional resistance

Answer 14

annulus

Question 15

axial rotation can strain the annulus in torsion, but ordinarily the _______ joints will protect it

Answer 15

zygapophyseal

Question 16

spiral fractures of long bones are another example of _______ _______ _______.

Answer 16

torsional load failure

Question 17

The external force acting to deform the material; measures the intensity of the force

Answer 17

stress

Question 18

magnitude of deformation as a result of the applied stress/loading; a measure of the degree of deformation

Answer 18

strain

Question 19

In general, strain is _______ to stress and the relationship is a constant for a given material and a particular type of deformation

Answer 19

proportional

Question 20

the maximum stress a tissue can withstand without permanent deformation

Answer 20

strength

Question 21

stress at the yield point of a material beyond which permanent deformation will occur

Answer 21

yield strength

Question 22

the maximal stress that a material can withstand prior to the initiation of failure

Answer 22

ultimate strength

Question 23

the stress at which the material actually breaks or ruptures

Answer 23

failure strength

Question 24

force per unit area required to deform a material, represented by the steepness (slope) of the stress/strain curve

Answer 24

ductility

Question 25

_______ tissues fail a low stress but can withstand a large strain

Answer 25

ductile (pliant)

Question 26

_______ tissues can withstand high stress but fail with relatively low strain

Answer 26

brittle (stiff)

Question 27

the total energy required to cause material failure

Answer 27

toughness - it takes a lot of energy to rupture a tough material

Question 28

Toughness can be estimated by observing the _______ _______ under the stress/strain curve.

Answer 28

total area

Question 29

_______ is an example material of high strength, low ductility (brittle), low toughness

Answer 29

bone

Question 30

_______ is an example material of moderate strength and ductility, high toughness

Answer 30

tendon

Question 31

_______ is an example material of low strength, high ductility, and moderate toughness

Answer 31

ligament

Question 32

ability to return to the original shape when load is removed

Answer 32

elasticity

Question 33

point at which the applied stress can lead to permanent deformation

Answer 33

yield point

Question 34

the nonlinear response of the material after the yield point - some degree of deformation will persist after removal of the stress

Answer 34

plastic region

Question 35

property of material to resist loads that produce shear or tensile forces

Answer 35

viscosity

Question 36

putty-like behavior: the linear deformation produced by tensile stress remains even after the stress is removed

Answer 36

viscous stretch

Question 37

name for when a material shows both properties of viscosity and elasticity

Answer 37

viscoelasticity

Question 38

Viscoelastic structures will show what three time dependent loading characteristics?

Answer 38

Creep, hysteresis, relaxation

Question 39

continued deformation over time when constantly loaded; due to expulsion of water

Answer 39

creep

Question 40

the corresponding eventual decrease in stress that will occur as fluid is no longer exuded

Answer 40

relaxation

Question 41

energy loss exhibited by viscoelastic materials when they are subjected to loading and unloading cycles

Answer 41

hysteresis

Question 42

Term for normal range of motion

Answer 42

toe region