Gn Ptha 1413 - Functional Anatomy - Mansfield And Neumann Book And Miele Lecture - Exam 1

Front 1

What is kinesiology? ***

Back 1

The study of movement utilizing
- musculoskeletal anatomy
- neuromuscular physiology
- biomechanics

Front 2

What is biomechanics? ***

Back 2

- the study of the physical principles and forces that act on the body

- consists of the areas of kinematics and kinetics

Front 3

What is kinematics? ***

Back 3

involves terms which describe body’s movements (flexion, extension, etc.)

describe motion of the body without regard to the forces that produce the motion

Front 4

What is kinetics? ***

Back 4

involves the study of forces which produce motion or maintain equilibrium of the body

Front 5

How many types of motion are there? ***

Back 5

four

there are four pathways through which the entire body or body segments can travel

Front 6

What are the four pathways through which the entire body or body segments can travel? ***

Back 6

1. rotary
2. translatory
3. curvilinear
4. general plane

Front 7

What is rotary motion? ***

Back 7

- angular

- movement occurring in a circular path or arc around a fixed axis in a curved path

- most joint movements are primarily rotatory

(e.g., motion occurring in a joint)

Front 8

What is translatory motion? ***

Back 8

- linear

- movement occurring more or less in a straight line

- movement of body as a whole is generally rectilinear

- translatory motion also occurs with joint movement (gliding)

Front 9

What is curvilinear motion? ***

Back 9

- movement occurs in a curved path

- combination of rotatory and translatory motions

- rotation of object/segment about axis while object and its axis is moving through space

[e.g., throwing a ball (shoulder rotates but arm moves through space)]

Front 10

What is general plane motion? ***

Back 10

- type of curvilinear motion

- segment rotates about axis while axis is translated through space by motion of adjacent segment(s)

- most movement of UE/LE are accomplished through general plane motion

(e.g., moving beverage to mouth)

Front 11

What is anatomical position? ***

Back 11

The arbitrary position used as the reference point from which movement or location of body structures can be described:

- standing upright and erect
- eyes facing forward
- feet, parallel, toes pointing forward
- arms at sides of body
- palms facing anteriorly

Front 12

What is a plane of motion? ***

Back 12

- an imaginary fixed plane which divides body into halves
- there are three cardinal planes, perpendicular to each other
- rotary motion occurs within planes of motion

Front 13

What is axis of movement? ***

Back 13

- an imaginary line perpendicular to corresponding plane
- movement occurs around this axis
- every angular movement of joint occurs in a plane and around an axis which is perpendicular to its plane

Front 14

Transverse/horizontal plane of motion and axis of movement ***

Back 14

- divides body into upper and lower halves

- longitudinal or vertical axis

- movements parallel to ground around longitudinal axis (rotation)

Front 15

Frontal/coronal plane of motion and axis of movement ***

Back 15

- divides body into front and back halves

- anterior-posterior or sagittal axis

- side-to-side movements (abduction and adduction)

Front 16

Sagittal plane of motion and axis of movement ***

Back 16

- divides body into right and left halves

- coronal or frontal axis (or medial-lateral)

- forward and backward movements (flexion and extension)

Front 17

List some rotary (angular) joint movements ***

Back 17

- flexion: bending, decreasing joint angle
- extension: straightening, increasing joint angle
- hyperextension: continuation of extension beyond anatomical position

- abduction: movement away from midline
- adduction: movement toward midline

- rotation: movement of segment around longitudinal (vertical) axis

- circumduction: combination of flexion, abduction, extension, and adduction

Front 18

List some translatory (linear) joint movements ***

Back 18

- compression: linear movement of segment toward joint

- distraction: linear movement of segment away from joint

- gliding: linear movement of one flat joint surface along an adjoining flat joint surface

Front 19

What is joint ROM? ***

Back 19

the quantity of rotatory (angular) motion of a joint

In physical therapy, it is measured in degrees, usually on a 180 degree scale

(goniometry - gonio: Latin for angle)

Front 20

What is force? ***

Back 20

- capacity to do work

- a push or pull exerted by one object or substance on another

Front 21

With reference to kinetics and the human body, how does force affect us? ***

Back 21

external and internal forces act on the human body

- external forces act on body from outside: gravity, wind, water, objects, other people

- internal forces act on body from within (pull of muscles and ligaments on bone, push of bone on bone or bone on soft tissue)

- internal forces are necessary for functional movements and for counteracting external forces

Front 22

What is a vector? ***

Back 22

a quantity (of force) having both
- magnitude and
- direction

Front 23

Forces are ______ quantities. ***

Back 23

vector

(they have magnitude and direction)

Front 24

Three characteristics of all vector forces ***

Back 24

- action line and direction

- magnitude (quantity of force)

- point of application - the greater the distance from the axis, the greater the force

Front 25

What is Newton's 3rd law? ***

Back 25

- for every action there is an equal and opposite reaction
(forces always come in pairs)

Front 26

Whenever two objects are in contact/touching, each.... ***

Back 26

exerts a force on the other

Front 27

Gravity exerts a force... ***

Back 27

on all objects at all times

Front 28

What is center of gravity (COG)? ***

Back 28

- a.k.a. "balance point"

- a hypothetical point at which the entire mass of an object is considered to be concentrated and which point the object can be balanced.

(Gravity acts at all points of an object or segment of an object, but its POINT OF APPLICATION is given as the COG)

Front 29

How is the COG located for a:
- symmetrical object?
- asymmetrical object?
- erect, bipedal human?
- body part? ***

Back 29

- COG of symmetrical object is located at geometric center of object (ball, cube)

- COG of asymmetrical object located toward heavier end/side (baseball bat/human body)

- erect bipedal human body as a single solid object has COG located approximately at S2 vertebral segment anterior to sacrum (depending on the proportions and weight distribution of person)

- each segment of the body also has its own COG (head, trunk, upper arm, forearm, hand, wrist, etc)

Front 30

How can the COG of a body change? ***

Back 30

depending on:

- position of object

- any weight added to or taken away from object (e.g., cast, pregnancy, amputation)

Front 31

Can the COG be outside the body? ***

Back 31

yes, sometimes

(e.g., elderly person using a walker)

Front 32

What is the line of gravity (LOG)? ***

Back 32

a vertical pull by gravity directly downward from COG

Front 33

What is base of support (BOS)? ***

Back 33

the area formed under the body by connecting all points in contact with the ground

Front 34

What is the definition of falling down?

Back 34

when the COG moves outside the BOS

Front 35

State 5 principles relating to stability of the body. ***

Back 35

1) The larger the BOS, the more stable the body; the smaller the BOS, the less stable the body, but the more easily mobility can be achieved (inversely related)

2) When COG/LOG are located near the center of BOS, stability is greatest; as COG/LOG move to edges/outside of BOS, stability lessens, but mobility is easier to achieve

3) Addition of weights/movement of body parts away from center of BOS will lessen stability. Body will seek stability by realignment to center of BOS through compensatory movements in opposite direction (why it's easier to carry a pail of water in each hand than it is to carry only one)

4) To maintain stability as force is being applied--widen BOS

5) The lower the COG of body, the greater the stability

Front 36

What are statics? ***

Back 36

- conditions under which an object remains in equilibrium (at rest) as a result of balanced forces action on it;

- therefore, the sum of all forces and counterforces acting on the object must equal zero

Front 37

What are dynamics? ***

Back 37

- conditions under which movement/acceleration of an object occurs as a result of unbalanced forces acting on it

- acceleration of an object is proportional to unbalanced forces acting on it and inversely proportional to mass of an object: a = F/m

Front 38

Acceleration of an object is... ***

Back 38

proportional to unbalanced forces acting on it and inversely proportional to mass of an object:

a = F/m

Front 39

Acceleration/movement increases when... ***

Back 39

force increases or mass decreases

Front 40

Are bedsores a static or dynamic situation?

Is standing still static or dynamic?

Back 40

both are dynamic

Front 41

All forces consist of.... ***

Back 41

two components (directions)

Front 42

Explain the two components of force. ***

Back 42

all forces consist of two components (directions): rotary force and translatory force

1) rotatory force - that portion of force applied toward rotational movement of lever; causes the lever to move around the axis (similar to a wrench)
Example: weight of object or gravity on segment at COG
Muscle action on bone which causes angular joint motion

2) translatory force - that portion of force applied toward linear movement of lever; acts in a parallel manner to the segment

Front 43

Describe the action of translatory force when acting parallel to a lever. ***

Back 43

- distraction – force component away from joint (good to increase mobility)

- compression – force component toward the joint (stability)

- muscle forces in the human body have large compression (translatory) components which contribute to joint stability

(again, mobility and stability inversely proportionate)

Front 44

Describe the action of translatory force when acting parallel to contacting surfaces. ***

Back 44

- shear force – results in linear movement (sliding) between two contacting surfaces; e.g., can occur between joint surfaces during muscle action or can occur between two layers of soft tissue/bone resulting in decubitus ulcers

- friction force – results in opposition to linear movement (sliding) between two surfaces; e.g., friction of sheet on skin as patient is slid to the side of bed, friction of sole of rubber shoes to prevent slipping, friction of rubber crutch tips, powder on board to decrease friction of leg in exercise, friction internally of bone on bone, or bone on muscle during movement

Front 45

What is an anatomical pulley? ***

Back 45

A bone or bony prominence around/over which a muscle or tendon passes; changes direction of muscle pull (e.g., shoulder abduction vice just lifting)

Front 46

What is the biomechanical importance of anatomical pulleys? ***

Back 46

- results in increase in rotatory ability although magnitude of force stays the same. Does this by:

1. changing the direction of muscle pull (action line) to a more perpendicular angle;

2. increasing distance of action line from axis (moment arm)

Example: deltoid muscle over head of humerus and acromion, or quadriceps over patella

Front 47

Definition of a lever system ***

Back 47

rigid bar (lever) being acted upon by forces or counterforces which tend to rotate the bar about a fixed point (axis)

Front 48

Name the levers and axes of the human body. ***

Back 48

bones = levers
joints = axes

center of gravity or bony segment = resistance (of gravity)
What does this mean?? Should the "or" be "of"???

Front 49

How do muscle insertions affect levers (bones)? ***

Back 49

muscle insertions = points of application of counterforce to overcome resistance (of gravity, etc.)

(origins OR insertions)


Center of gravity or bony segment = resistance (of gravity) ("of" bony segment??)

If the COG is where mass is concentrated and gravity is applied, then the muscle insertions (or origins) act at that point to overcome gravity?

Front 50

What are the three types of levers? ***

Back 50

- first class
- second class
- third class

Front 51

What is a first class lever? ***

Back 51

- axis/fulcrum between muscle force and resistance (between the internal and external forces)

- best designed for balance (e.g., seesaw)

- very few in human body; e.g., neck extensors to balance head on 1st vertebra

Front 52

What is a second class lever? ***

Back 52

- resistance between muscle force and axis
- (external force is between the axis and internal force)

- axis/fulcrum is at end of bony lever, and the internal moment arm is longer than the external moment arm

- effort/movement arm is longer than resistance arm (e.g., wheelbarrow)

- best designed for power

- rare in human body, except when muscle is resistance force and gravity is the effort force as in eccentric (lengthening) contraction of quads, biceps

Front 53

What is a third class lever? ***

Back 53

- muscle force is between resistance and axis
- internal and external moment arms are reversed from second class lever

- resistance arm is longer than effort/movement arm (e.g., hammer) and therefore gravity has more leverage than muscle

- best designed for ROM and speed

- most common lever type in human body

Front 54

Another explanation of
- first-class lever
- second-class lever
- third-class lever

Back 54

First-class lever (balance)
- fulcrum located between internal and external force (e.g., seesaw)

Second-class levers (favor force/power)
- axis of rotation located at one end of the bony lever; internal moment arm always longer than the external moment arm (e.g., wheelbarrow)

Third-class levers (favor speed and ROM)
- axis of rotation located at one end of the bony lever; internal moment arm always smaller than the external moment arm

Moment arm – perpendicular line in relationship to axis and point of force

Front 55

Upon what does amount of force generated across a joint depend? ***

Back 55

- amount of force exerted

- distance between force and axis of rotation (moment arm)

Front 56

Where is torque generated? ***

Back 56

- internal torques are generated internally (e.g., muscle)

- external torques are generated externally (e.g., gravity)

Front 57

What is torque? ***

Back 57

- the rotational equivalent of force

- moment of force

- ability of any force (effort or resistance) to cause rotation of a lever about an axis; determined by:

1) magnitude of effort or resistance force
2) distance from the action line of force and axis (shortest line drawn perpendicular to action line and intersecting axis)

(e.g., In pushing open a door greater torque is required the closer your push is in proximity to the hinges

Front 58

What is mechanical advantage (MA)? ***

Back 58

occurs when only a small force is needed to overcome a large resistance

MA of a lever refers to the relation between the length of the effort (force) arm and the resistance arm
- 2nd class levers demonstrate greatest MA (EA > RA)
- 3rd class levers demonstrate least MA (RA > EA)

Human body is at a “mechanical disadvantage” because it is basically a 3rd class lever system

(EA – effort arm; RA – resistance arm)

Front 59

How can mechanical advantage (MA) be improved? ***

Back 59

greater MA can be achieved by either lengthening effort arm or decreasing resistance arm

Examples of applying MA:
1. a load carried closer to body than holding it out/away
2. a screw driver to pry off paint lid instead of fingers
3. anatomical pulleys

Front 60

What are the two perspectives of movement at a joint? ***

Back 60

- open-chain motion

- closed-chain motion

Front 61

What is open-chain motion at a joint? ***

Back 61

- distal segment moves
- proximal segment stays relatively fixed

Front 62

What is closed-chain motion at a joint? ***

Back 62

- proximal segment moves
- distal segment stays relatively fixed

Front 63

What is the reason for the convex-concave joint relationship? ***

Back 63

- improves fit and stability
- properly guides motion

Front 64

Why do the fundamental movements of arthrokinematics vary? ***

Back 64

because they depend on whether the concave articular surface is moving on a fixed convex surface or vice versa

Front 65

What is "roll"? ***

Back 65

multiple points along one rotating articular surface contact multiple points on another articular surface

(e.g., a tire rotating across a stretch of pavement)

Front 66

What is "slide"? ***

Back 66

single point on one articular surface contacts multiple points on another articular surface

(e.g., a stationary tire skidding across a stretch of icy pavement)

Front 67

What is "spin"?

Back 67

single point on one articular surface rotates on a single point on another articular surface

(e.g., rotating toy top spinning on one spot on the floor)

Front 68

When do roll and slide occur in the same direction? ***

Back 68

When the concave joint surface moves about a stationary convex joint surface

Front 69

When do roll and slide occur in opposite directions? ***

Back 69

When the convex joint surface moves about a stationary concave joint surface

Front 70

What does roll-and-opposite-direction slide serve to do? ***

Back 70

maintain articular stability

Front 71

What does roll-and-same-direction slide serve to do? ***

Back 71

maintain firm surface contact, proper joint alignment, and congruency

Front 72

Spin always occurs... ***

Back 72

about a central longitudinal axis of rotation

Front 73

Arthrokinematic functional considerations dictate that motion may be hindered by...

Back 73

issues like impingement syndrome

(without appropriate roll and slide, some tissues will be pinched/compressed and others stretched inappropriately)

Front 74

Which of the following motions occurs around a medial-lateral axis of rotation? ***

a. Shoulder abduction
b. Knee flexion
c. Shoulder extension
d. A and B
e. B and C

Back 74

e. B and C

Front 75

Which of the following lever systems is most commonly used by the musculoskeletal system? ***

a. First class
b. Second class
c. Third class

Back 75

c. third class

Front 76

When a convex member of a joint is moving over a relatively stationary concave member, the arthrokinematic roll and slide occur: ***

a. in the same direction
b. in opposite directions

Back 76

b. in opposite directions

Front 77

Which of the following terms describes the proximal attachment of a muscle? ***

a. caudal
b. insertion
c. cephalad
d. origin
e. A and B

Back 77

d. origin

Front 78

Which of the following lever systems ALWAYS provides good leverage, allowing an external load to be lifted with comparatively less muscular force? ***

a. first class
b. second class
c. third class

Back 78

b. second class

Front 79

The torque generated by a muscle is calculated by: ***

a. dividing the muscular force by the internal moment arm
b. multiplying the muscular force by the external moment arm
c. dividing the muscular force by the external moment arm
d. multiplying the muscular force by the internal moment arm

Back 79

d. multiplying the muscular force by the internal moment arm

Front 80

A closed-chain motion: ***

a. always provides larger ranges of motion than an open-chain motion
b. occurs when the distal segment of the joint moves relative to a stationary proximal segment
c. occurs when the proximal segment of the joint moves relative to a fixed distal segment
d. is typically not used when treating a patient

Back 80

c. occurs when the proximal segment of the joint moves relative to a fixed distal segment

Front 81

The shoulder is ______ to the elbow. ***

a. caudal
b. proximal
c. distal
d. deep
e. A and B

Back 81

b. proximal

Front 82

Internal rotation of the shoulder occurs about a(n) _____ axis of rotation. ***

a. anterior-posterior
b. medial-lateral
c. longitudinal (or vertical)
d. reciprocal

Back 82

c. longitudinal (or vertical)

Front 83

The term osteokinematics describes the: ***

a. motion between joint surfaces
b. motion of bones relative to the three cardinal planes
c. forces transferred from muscles through joints
d. force of a muscle contraction acting on an internal moment arm

Back 83

b. motion of bones relative to the three cardinal planes

Front 84

Which of the following statements is true? ***

a. the proximal attachment of a muscle is known as the insertion
b. a vector is a representation of a force's magnitude and direction
c. flexion of the hip occurs in the frontal plane
d. a closed-chain motion refers to the distal segment of a joint moving on a relatively fixed proximal segment

Back 84

b. a vector is a representation of a force's magnitude and direction

Front 85

Second-class lever systems favor range of motion and speed? ***

a. true
b. false

Back 85

b. false (third class do)

Front 86

Which of the following movements occur in the frontal plane? ***

a. shoulder adduction
b. hip flexion
c. pronation of the forearm
d. A and C
e. B and C

Back 86

a. shoulder adduction

Front 87

Which of the following movements occur about a longitudinal or vertical axis of rotation? ***

a. internal rotation of the shoulder
b. extension of the shoulder
c. flexion of the hip
d. abduction of the hip

Back 87

a. internal rotation of the shoulder

Front 88

Which of the following movements occur in the sagittal plane? ***

a. extension of the hip
b. flexion of the shoulder
c. internal rotation of the shoulder
d. A and B
e. all of the above

Back 88

d. A and B

Front 89

Which of the following movements occur about an anterior-posterior axis of rotation? ***

a. extension of the hip
b. supination of the forearm
c. abduction of the hip
d. internal rotation of the shoulder

Back 89

c. abduction of the hip

Front 90

Based on a front view of the shoulder, which motion will occur by a muscular line of pull that courses lateral and superior to the anterior-posterior axis of rotation? ***

a. shoulder abduction
b. shoulder flexion
c. shoulder internal rotation
d. plantar flexion

Back 90

a. shoulder abduction

Front 91

Which of the following motions occurs about a vertical axis of rotation? ***

a. internal rotation of the shoulder
b. external rotation of the shoulder
c. rotation of the head and neck
d. A and B
e. all of the above

Back 91

e. all of the above

Front 92

Which of the above motions would be produced by a muscular line of pull that courses anterior to the medial-lateral axis of rotation? ***

a. hip flexion
b. shoulder extension
c. plantar flexion
d. shoulder adduction

Back 92

a. hip flexion

Front 93

The shoulder adductor muscles are antagonists to ***

a. shoulder abductors
b. shoulder flexors
c. shoulder extensors
d. shoulder internal rotators

Back 93

a. shoulder abductors

Front 94

Third-class levers favor range of motion and speed over force. ***

a. true
b. false

Back 94

a. true

Front 95

A muscle that courses anterior to a medial-lateral axis of rotation will produce motion in the sagittal plane. ***

a. true
b. false

Back 95

a. true

Front 96

The term "strength" refers solely to the force that a muscle can produce, not its torque production. ***

a. true
b. false

Back 96

b. false (measuring strength measures torque production)

Front 97

A "resultant force" refers to the amount of force that is lost because of tissue elasticity. ***

a. true
b. false

Back 97

b. false (it is the combined force of two vectors)

Front 98

A first-class lever ALWAYS favors force over range of motion. ***

a. true
b. false

Back 98

b. false (a second class lever does)

Front 99

"Passive movements" refer to forces that produce body movement other than that caused by muscular activation.
***

a. true
b. false

Back 99

a. true

Front 100

A joint that allows 2 degrees of freedom is likely to permit volitional motion in all three planes. ***

a. true
b. false

Back 100

b. false (degrees of freedom = planes of motion)

Front 101

A joint must allow motion in at least two planes in order for it to circumduct. ***

a. true
b. false

Back 101

a. true

Front 102

A motion such as flexing and extending the elbow with the hand free is an example of a closed-chain motion. ***

a. true
b. false

Back 102

b. false (open chain)

Front 103

When a convex joint surface moves about a stationary concave joint surface, the arthrokinematic roll and slide occur in the same direction. ***

a. true
b. false

Back 103

b. false (opposite directions)

Front 104

What is a joint? ***

Back 104

- an articulation

- any connection between 2 or more bones in the human body

Front 105

What are the two necessary components of joint design? ***

Back 105

- stability

- mobility

Front 106

A more stable joint has a _____ complex design. ***

Back 106

less

Front 107

A more mobile joint has a ____ complex design. ***

Back 107

more

Front 108

What is sacrificed for increased mobility in a joint? ***

Back 108

stability

Front 109

What is sacrificed for increased stability in a joint? ***

Back 109

mobility

Front 110

Human joints generally serve a dual function of both mobility and stability with one or the other as the _____ _____. ***

Back 110

primary function

Front 111

Which of the following joints is most stable? ***

A. sternoclavicular
B. hip
C. shoulder
D. elbow

Back 111

A. sternoclavicular

Front 112

Which of the following has the least amount of mobility? ***


A. sternoclavicular
B. hip
C. shoulder
D. elbow

Back 112

A. sternoclavicular

Front 113

What are the two broad categories of joints? ***

(Bonus points if you can name the sometimes-used third category.)

Back 113

- synarthroses (nonsynovial, immobile)
- diarthroses (synovial, mobile)

- amphiarthroses (sometimes used for somewhat mobile joints)

Front 114

What is a synarthrosis? ***

Back 114

- nonsynovial joint

- nonmoveable or only slightly movable joints

- designed for stability

- simple design, union of bone to bone with connective tissue “cement”

Front 115

Two types of synarthroses? ***

Back 115

- fibrous joints--fibrous connective tissue directly unites bone to bone

- cartilaginous joints--cartilaginous connective tissue directly unites bone to bone

Front 116

Examples of fibrous synarthroses? ***

Back 116

- suture joints of skull

- tooth joints (gomphoses)

- interosseous membrane connections (syndesmoses; e.g., between tibia and fibula)

Front 117

Examples of cartilaginous synarthroses? ***

Back 117

- symphysis (e.g., pubic symphysis)

- synchondrosis (e.g., 1st chondrosternal joint, vertebral joints)

Front 118

Degrees of freedom in a hinge joint: ***

Back 118

1

Front 119

Degrees of freedom in a pivot joint: ***

Back 119

1

Front 120

Degrees of freedom in an ellipsoid joint: ***

Back 120

2

Front 121

Degrees of freedom in a ball-and-socket joint: ***

Back 121

3

Front 122

Degrees of freedom in a plane joint: ***

Back 122

variable

Front 123

Degrees of freedom in a saddle joint: ***

Back 123

2

Front 124

Degrees of freedom in a condyloid joint: ***

Back 124

2

Front 125

Primary motions of a hinge joint: ***

Back 125

- flexion

- extension

Front 126

Primary motions of a pivot joint: ***

Back 126

spinning of one member about a single axis of rotation

Front 127

Primary motions of an ellipsoid joint: ***

Back 127

- flexion/extension

- abduction/adduction (or deviation--e.g., radial and ulnar in radiocarpal joint)

Front 128

Primary motions of a ball-and-socket joint: ***

Back 128

- flexion/extension
- abduction/adduction
- internal/external rotation

Front 129

Primary motions of a plane joint: ***

Back 129

typical motions include a slide or rotation, or both

Front 130

Primary motions of a saddle joint: ***

Back 130

biplanar motion; generally excluding a spin

Front 131

Primary motions of a condyloid joint: ***

Back 131

biplanar motion

Front 132

Mechanical analogy for a hinge joint: ***

Back 132

door hinge

Front 133

Mechanical analogy for a pivot joint: ***

Back 133

doorknob

Front 134

Mechanical analogy for an ellipsoid joint: ***

Back 134

flattened convex ellipsoid paired with a concave trough

Front 135

Mechanical analogy for a ball-and-socket joint: ***

Back 135

spherical convex surface paired with a concave cup

Front 136

Mechanical analogy for a plane joint: ***

Back 136

book sliding or spinning on a table

Front 137

Mechanical analogy for a saddle joint: ***

Back 137

horseback rider on a saddle

Front 138

Mechanical analogy for a condyloid joint: ***

Back 138

spherical convex surface paired with a shallow concave cup

Front 139

Anatomic examples of a hinge joint: ***

Back 139

- humeroulnar joint (elbow)

- interphalangeal joint (PIP/DIP)

Front 140

Anatomic examples of a pivot joint: ***

Back 140

- proximal radioulnar joint

- atlantoaxial joint (C1-C2/atlas-axis)

Front 141

Anatomic examples of a ellipsoid joint: ***

Back 141

radiocarpal joint

Front 142

Anatomic examples of a ball-and-socket joint: ***

Back 142

- glenohumeral joint (shoulder)

- hip joint

Front 143

Anatomic examples of a plane joint: ***

Back 143

- intercarpal joints

- intertarsal joints

Front 144

Anatomic examples of a saddle joint: ***

Back 144

- carpometacarpal joint of the thumb

- sternocavicular joint

Front 145

Anatomic examples of a condyloid joint: ***

Back 145

- tibiofemoral (knee) joint

- metacarpophalangeal joint (knuckles)

Front 146

What is the difference between a fibrous joint and a cartilaginous joint? ***

Back 146

a fibrous joint is immobile, a cartilaginous joint is not

Front 147

What is a diarthrosis? ***

Back 147

- a synovial joint

- a freely movable joint

Front 148

Characteristics of a diarthrosis: ***

Back 148

- synovial joint
- freely movable
- no cartilaginous tissue connecting bone to bone
- ends of bony components are free to move in relation to one another
- designed for mobility, thus less stable
- complex design

Front 149

Most joints in the body are: ***

Back 149

synovial

Front 150

What are the components of a synovial joint? ***

Back 150

- capsular ligaments
- joint capsule
- synovial membrane
- synovial fluid
- bony end components with articular cartilage
- joint cavity (filled with synovial fluid)

OR PER THE BOOK:
- synovial fluid
- synovial membrane
- articular cartilage
- articular capsule
- capsular ligaments
- blood vessels
- sensory nerves

and sometimes:
- intraarticular discs/menisci
- fat pads
- peripheral labrum
- synovial plicae

Front 151

What is a joint capsule? ***

Back 151

fibrous connective tissue which encloses the ends of bony components

Front 152

Describe the layers of a joint capsule. ***

Back 152

Outer layer--attaches capsule to bone
- highly innervated
- poorly vascularized
- sensitive to motion, compression, tension, vibration pain; slow to heal

Inner layer--lined with synovial membrane that produces synovial fluid
- poorly innervated
- highly vascularized
- insensitive to deformations, but vasodilates and vasoconstricts with heat/cold; entry point for nutrients, exit point for wastes (part of lymphatic drainage system)

Front 153

Describe a joint cavity. ***

Back 153

- formed by the joint capsule

- filled with synovial fluid

Front 154

What is synovial fluid? ***

Back 154

- thick, clear fluid produced by synovial membrane

- lubricates articulating joint surfaces, decreases friction, provides nourishment to cartilaginous structures in joint (such as articular/hyaline cartilage, discs, menisci, etc.)

Front 155

Describe the bony end components of a synovial joint. ***

Back 155

- enclosed by the joint capsule
- located inside joint cavity
- articulate with, but not united to each other
- covered with hyaline cartilage

Front 156

Describe the hyaline cartilage of the articulating surfaces of a synovial joint. ***

Back 156

- thin covering on ends of articulating bones
- forms a low-friction surface
- no neurovascular supply--nourishment comes from synovial fluid

Front 157

What other cartilaginous structures may be found in a synovial joint? ***

Back 157

wedges of cartilage such as:
- discs
- menisci
- plates
- labrums

Front 158

What purpose do other cartilaginous structures (e.g., menisci, discs, etc.) serve in the synovial joint? ***

Back 158

- increase stability
- provide shock absorption
- facilitate movement

Front 159

From where do other cartilaginous structures (e.g., menisci, discs, etc.) receive their nourishment? ***

Back 159

synovial fluid

Front 160

What is the purpose of ligaments, tendons, and muscles in synovial joints? ***

Back 160

- reinforce the capsule
- muscle provides active motion (which in turn "milks" the joint and gets the nourishing synovial fluid moving)

Front 161

What are bursae? ***

Back 161

- fluid-filled, pad-like sacs located in areas of excessive friction

- often near joints where moving structures are in tight approximation

- filled with synovial fluid

Front 162

Where are bursae commonly found (between what types of tissue)? ***

Back 162

- subcutaneous bursae: between skin and bone

- subtendinous bursae: between tendon and bone

- submuscular bursae: between muscle and bone

Front 163

Into what three main categories are synovial joints divided? ***

Back 163

- into three main categories based on number of axes about which motion occurs (degrees of freedom)

- these categories are then divided on basis of shape of bony end components
-- uniaxial synovial
-- biaxial synovial
-- triaxial synovial

Front 164

Describe a uniaxial synovial joint. ***

Back 164

- diarthrodial
- one plane/axis of movement
- one degree of freedom

Front 165

What types of joints are considered uniaxial? ***

Back 165

- hinge joint (flex/extend)
- pivot joint (rotate)

Front 166

Describe a biaxial synovial joint. ***

Back 166

- diarthrodial
- two planes/axes of movement
- two degrees of freedom

Front 167

What types of joints are considered biaxial? ***

Back 167

- condyloid/ellipsoid
- saddle joint

(both are able to flex/extend, abduct/adduct)

Front 168

Describe a triaxial synovial joint. ***

Back 168

- diarthrodial
- three planes/axes of movement
- three degrees of freedom

Front 169

What types of joints are considered triaxial?

Back 169

- plane joint (gliding/rotation in all planes)

- ball-and-socket joint (flexes/extends, abducts/adducts, rotates)

Front 170

What is a kinematic chain (in engineering and in the human body)? ***

Back 170

a series of rigid links (bones) interconnected by joints

Front 171

What are the two types of kinematic chains in the human system? ***

Back 171

- closed kinematic chain

- open kinematic chain

Front 172

What is a closed kinematic chain? ***

Back 172

- distal segment is connected and does not move freely in space

- motion of one link at one joint will produce motions at all other joints in system in a predictable manner (e.g., squatting)

Front 173

What is an open kinematic chain? ***

Back 173

- distal segment terminates free in space

- motion of one link at one joint occurs without motion at adjacent joint

- motion does not occur in a predictable manner

(e.g., waving)

Front 174

A change in the function/structure of one joint in a system will generally... ***

Back 174

affect function of adjacent joints in the system

(e.g., decreased knee ROM results in increased hip/ankle movements to clear foot during ambulation)

(This is why knee pain will often lead to hip and back pain, and also why we try to get the patient back to normal gait ASAP--to protect the other joints from injury.)

Front 175

What is a close-packed joint position? ***

Back 175

- joint surfaces are in full contact
- ligaments and capsule are maximally taut
- position of discomfort when joint is edematous

Front 176

What is an open-packed joint position? ***

Back 176

- ligaments and capsule are slack and joint play is present
- position of comfort when joint is edematous
- ideal position for joint mobilization (less friction)

Front 177

All _____ ______ have a close-packed or an open-packed position. ***

Back 177

synovial joints

Front 178

What does movement in and out of close-packed position help do? ***

Back 178

pump nutrients and wastes into and out of the joint

Front 179

What is arthrokinematics? ***

Back 179

description of movement of bone surfaces within a joint when a bone moves through ROM (motion occurring between joint articular surfaces):

- roll
- slide
- spin
- combination

These combinations of motion produce curvilinear motion and a moving axis of motion…helps increase overall joint ROM.

Front 180

What is osteokinematics? ***

Back 180

description of bone movement when bone moves through arc around joint axis:
- flexion/extension
- abduction/adduction

describes motion of bones relative to three cardinal planes of the body
- sagittal
- frontal/coronal
- transverse/horizontal

Front 181

What two types of motion are necessary for normal ROM? ***

Back 181

- osteokinematics and
- arthrokinematics

Front 182

How are rotation angular movements measured? ***

Back 182

with a goniometer

Front 183

What is normal (anatomic) ROM? ***

Back 183

amount of joint motion available within anatomic limits of the joint structure

Front 184

What determines normal (anatomic) ROM? ***

Back 184

- shape of joint surfaces
- surrounding soft tissue structures (e.g., adipose)
- joint capsules, ligaments
- muscle bulk

Front 185

Normal (anatomic) ROM may normally exhibit what types of limitations? ***

Back 185

- bony limitations (e.g., hard end field at elbow--olecranon process cannot go further into olecranon fossa)

- soft tissue limitations (e.g., bodybuilder with huge biceps will have decreased elbow flexion)

Front 186

What is pathologic ROM? ***

Back 186

occurs when:
- joint motion exceeds normal limits (hypermobility), or
- is less than normal

Front 187

What is the common result of hypermobility? ***

Back 187

decreased stability of the joint

(remember the mobility/stability tradeoff)

Front 188

What does hypomobility often lead to? ***

Back 188

contracture (shortening of soft tissue structures around the joint)

Front 189

What type of tissue forms all structures of the joint? ***

Back 189

connective

(forms ligaments, tendons, bursae, cartilage, discs, menisci, capsules, bones, etc.)

Front 190

What are the primary components of connective tissue? ***

Back 190

- fibrous component (collagen and elastin framework)

- ground substance for support

Front 191

What is collagen? ***

Back 191

- non-elastic component
- tensile strength of steel
- responsible for tissue’s functional integrity

Front 192

What is Type I collagen? ***

Back 192

- thick, rugged fibers that resist elongation

- compose ligaments, tendons, and fibrous capsules

Front 193

What is Type II collagen? ***

Back 193

- thinner and less stiff than type I fibers

- provide a flexible woven framework for maintaining the general shape and consistency of structures

Front 194

What is elastin? ***

Back 194

- tissue that is elastic in nature

- resist (tensile) forces but have more “give” when elongated

- deforms under pressure and returns to original state when force removed

- can be useful in preventing injury because they allow the tissue to “bend, but not break”

Front 195

What is the role of cells in joint structures? ***

Back 195

responsible for the maintenance and repair of tissues that constitute joints

Front 196

What is the general proportion of collagen:elastin in connective tissue? ***

Back 196

relative proportion varies by structure, but in general

collagen > elastin

Front 197

All connective tissue exhibits _______, which enables it to deform under distractive or compressive force and return to the original state after removal of force.

Back 197

viscoelasticity

Front 198

What is viscoelasticity? ***

Back 198

- a property of all connective tissue

- enables it to deform under distractive or compressive force and return to the original state after removal of force

Front 199

What is important to remember about the viscoelasticity of connective tissue? ***

Back 199

- return to original state is not immediate

- the longer the application of force, the longer it takes to return from deformation

Front 200

What is creep? ***

Back 200

- deformation of a structure due to constant load

the greater the force and longer the duration, the greater the creep

Front 201

What is plastic range? ***

Back 201

when connective tissue is exposed to sudden, prolonged or excessive forces, the ability of the tissue to recover is exceeded and it is permanently deformed and unable to return to original state

(e.g., ligamentous laxity--pull on tibia to check ACL)

Front 202

What is tissue failure? ***

Back 202

- when plastic range is exceeded

- results in ruptures, fractures, avulsions (takes a little bone with it when ligament tears away)

Front 203

Mechanical specialization of dense irregular connective tissue? ***

Back 203

- binds bones together

- restrains unwanted movement of joints

Front 204

Anatomic location of of dense irregular connective tissue? ***

Back 204

- comprises ligaments and

- tough external layer of joint capsules

Front 205

Fiber types of of dense irregular connective tissue? ***

Back 205

- primarily type I collagen fibers

- low elastin fiber content

Front 206

Clinical correlation of dense irregular connective tissue? ***

Back 206

rupture of the lateral collateral ligaments of the ankle can lead to medial-lateral instability of the talocrural joint

Front 207

Mechanical specialization of articular cartilage? ***

Back 207

resists and distributes compressive and shear forces transferred through articular surfaces

Front 208

Anatomic location of articular cartilage? ***

Back 208

covers the ends of articulating bones in synovial joints

Front 209

Fiber types of articular cartilage? ***

Back 209

- high type II collagen fiber content

- fibers help anchor cartilage to bone

Front 210

Clinical correlation of articular cartilage? ***

Back 210

wear and tear of articular cartilage often decreases its effectiveness in dispersing joint compression forces, often leading to osteoarthritis and joint pain

Front 211

Mechanical specialization of fibrocartilage? ***

Back 211

- provides support and stabilization to joints

- primarily functions to provide shock absorption by resisting and dispersing compressive and shear forces

Front 212

Anatomic location of fibrocartilage? ***

Back 212

comprises the
- intervertebral discs of the spine
- menisci of the knee

Front 213

Fiber types of fibrocartilage? ***

Back 213

multidirectional bundles of type I collagen

Front 214

Clinical correlation of fibrocartilage? ***

Back 214

tearing of the intervertebral disc within the vertebral column can allow the central nucleus pulposus (gel) to escape and press on a spinal nerve or nerve root

Front 215

Mechanical specialization of bone? ***

Back 215

- forms the primary supporting structure of the body

- provides a rigid lever to transmit muscle force to move and stabilize the body

Front 216

Anatomic location of bone? ***

Back 216

forms the internal levers of the musculoskeletal system

Front 217

Fiber types of bone? ***

Back 217

specialized arrangement of type I collagen that provides a framework for hard mineral salts

Front 218

Clinical correlation of bone? ***

Back 218

osteoporosis of the spine results in loss of mineral and bone content; may result in fractures of the vertebral body

Front 219

What is stress with respect to joints? ***

Back 219

forces created within a structure when an external load is applied

(e.g., muscle contractions, weight bearing)

Front 220

What is strain with respect to joints? ***

Back 220

deformation of structure as a result of stress

(this is a force; do not confuse it with the strain that happens to a pulled muscle)

Front 221

What is tensile stress with respect to joints? ***

Back 221

- stress created within a structure when two externally applied loads are opposite in directions

- results in tensile strain (deformation)
(also what we refer to as, or a form of, distraction?)

Front 222

What is compressive stress with respect to joints? ***

Back 222

- stress created within a structure when two externally applied loads are toward each other

- results in compressive strain (deformation)

Front 223

What is shear stress with respect to joints? ***

Back 223

stress created when applied forces are equal, parallel, and applied in opposite direction

Front 224

Why are normal amounts of stress and strain on joint structures necessary? ***

Back 224

- to maintain and increase strength of tendons and ligaments

- to increase density and strength of bone

- to ensure nourishment of cartilaginous structures

Front 225

What happens to joints in the absence of normal stress/strain or with application of excessive stress/strain? ***

Back 225

- absence of normal stress/strain can decrease bone density/strength

- excessive stress/strain can lead to structure failure

Front 226

Which joints are more likely to be affected by pathologies, simple or complex? Why? ***

Back 226

- complex

- because more structures are involved

Front 227

What are some of the general effects of disease, injury, immobilization, and overuse on joint structures? ***

Back 227

can initiate a cascade of events, for example:
- more wear and tear, especially on the less stable complex joints
- breakdown of one component eventually affects other structures in that joint
- which results in decreased stability and/or mobility
- which causes decreased function (and likely damage to other joints--e.g., knee damage affects hip and back)

Front 228

Describe RA ***

Back 228

- rheumatoid arthritis
- autoimmune disease
- malfunction of synovial membrane which alters production of synovial fluid
- lubrication of joint affected
- hyaline cartilage deteriorates (eaten by synovial fluid autoimmune reaction)
- subchondral bone exposed
- deformation of underlying bone tissue

Front 229

Describe OA ***

Back 229

- osteoarthritis
- erosion and splitting of cartilage that occurs with stress
- increased friction between articulating surfaces
- erosion occurs

Front 230

Taber's definition of arthritis ***

Back 230

Slides say to look this up

Front 231

What is a joint injury? ***

Back 231

- torn ligament = lack of joint support; abnormal separation of joint surfaces on side of tear and abnormal compression on opposite side

- torn cartilage = restricted ROM

both are very painful

Front 232

How are joints nourished? ***

Back 232

- nourishment derived solely from back and forth flow of synovial fluid

- flow of fluid in and out of cartilage occurs with joint motion

Front 233

How does immobilization of a joint adversely affect that joint? ***

Back 233

- lack of joint compression/ROM decreases movement of fluids

- cartilage nutrition is then adversely affected and deterioration occurs

resulting in:
- soft tissue shortening (contractures)
- adhesions in synovial membrane
- atrophy of cartilage
- osteoporosis
- weakened ligaments and/or muscles

Front 234

What are the two broad categories of immobilization? ***

Back 234

- external (cast) or

- internal (inflammation, edema)

Front 235

What is joint overuse? ***

Back 235

constant or repetitive loading (compressive or tensile) of articular structures that can result in tissue deformation

Front 236

What effects can constant loading in prolonged positions have? ***

Back 236

constant loading in prolonged positions (standing, sitting) subjects joints and their structures to deformation and creep

Front 237

What effects can constant tensile loads have on ligaments? ***

Back 237

constant tensile loads subject ligaments to creep/excessive lengthening

Front 238

What effects can constant compressive loads have on cartilage? ***

Back 238

constant compressive loads subject cartilage to creep/excessive deformation

Front 239

What effects can repetitive loading have on joint structures? ***

Back 239

- repetitive loading can result in failure of joint structures, as they do not have time to recover to original dimensions before being subjected to another load cycle

- overuse syndrome often affects athletes, dancers, musicians, factory/office workers

Front 240

What is failure of a joint structure due to repetitive loading called? ***

Back 240

- overuse syndrome

- cumulative trauma disorder (repetitive use disorders)

Front 241

Which of the following types of joints allows the least amount of motion? ***

a. Diarthrosis
b. Synarthrosis
c. Condyloid
d. Amphiarthrosis

Back 241

b. Synarthrosis

Front 242

Which of the following joints allows only 1 degree of freedom? ***

a. Ellipsoid
b. Ball-and-socket
c. Hinge
d. Saddle
e. B and C

Back 242

c. Hinge

Front 243

Which of the following connective tissues are designed to "give" when stretched, thereby resisting injury? ***

a. Type I collagen fibers
b. Type II collagen fibers
c. Elastin
d. Glycosaminoglycans

Back 243

c. Elastin

Front 244

The intervertebral discs of the spine are primarily composed of which type of connective tissue? ***

a. dense, irregular connective tissue
b. articular cartilage
c. fibrocartilage
d. bone

Back 244

c. fibrocartilage

Front 245

Which of the following structures connect bone to bone and function primarily to resist internal and external forces? ***

a. tendons
b. ligaments
c. articular cartilage
d. bursae

Back 245

b. ligaments

Front 246

The glenohumeral joint of the shoulder is an example of which type of joint? ***

a. Saddle
b. Ball-and-socket
c. Ellipsoid
d. Pivot

Back 246

b. Ball-and-socket

Front 247

Which of the following is an example of a condyloid joint? ***

a. Sternoclavicular
b. Acromioclavicular
c. Tibiofemoral (knee)
d. Metacarpophalangeal
e. C and D

Back 247

e. C and D

Front 248

Which of the following statements is true? ***

a. Pivot joints typically allow 3 degrees of freedom
b. Cancellous bone is porous and typically lines the inner portions of a bone
c. Ground substance typically has almost no water content
d. Tendons connect bone to bone

Back 248

b. Cancellous bone is porous and typically lines the inner portions of a bone

Front 249

Immobilization of a joint generally leads to greater stiffness of the surrounding connective tissues. ***

a. True
b. False

Back 249

a. True

Front 250

The sutures of the skull are a good example of an amphiarthroidal joint. ***

a. true
b. false

Back 250

b. false (synarthrodial)

Front 251

Cortical bone is dense and strong, typically lining the outermost portions of a bone. ***

a. True
b. False

Back 251

a. True

Front 252

The humerus and the tibia are both bones considered to be part of the axial skeleton. ***

a. true
b. false

Back 252

b. false (appendicular)

Front 253

Bone is considered a non-dynamic tissue with limited ability to remodel itself. ***

a. true
b. false

Back 253

b. false (bone IS dynamic, with SIGNIFICANT ability to remodel itself)

Front 254

Saddle joints, condyloid joints, and ellipsoid joints all permit motion in at least two planes. ***

a. True
b. False

Back 254

a. true

Front 255

Which joints allow motion to occur in only two planes? ***

a. Hinge
b. Ellipsoid & Ball-and-socket
c. Ball-and-socket & Condyloid
d. Ellipsoid & Condyloid

Back 255

d. Ellipsoid & Condyloid

Front 256

Which of the following joints is considered the most mobile? ***

a. Hinge
b. Ellipsoid
c. Ball-and-socket
d. Condyloid

Back 256

c. Ball-and-socket

Front 257

Which of the following joints allows flexion and extension? ***

a. Hinge & Ellipsoid
b. Ellipsoid & Ball-and-socket
c. Ball-and-socket & Condyloid
d. All of the above

Back 257

d. All of the above

Front 258

Which of the following joints allows motion in just one plane? ***

a. Hinge
b. Hinge & Ball-and-socket
c. Ellipsoid
d. Condyloid

Back 258

a. Hinge

Front 259

Which of the following joints does (do) not allow motion to occur in the frontal plane? ***

a. Condyloid
b. Hinge & Condyloid
c. Hinge & Ball-and-socket
d. Ellipsoid & Ball-and-socket

Back 259

b. Hinge & Condyloid

Front 260

Which of the following joints allow(s) motion to occur about all three axes of rotation? ***

a. Hinge
b. Ellipsoid
c. Ball-and-socket
d. Condyloid
e. Ellipsoid & Ball-and-socket

Back 260

c. Ball-and-socket

Front 261

What is translation?

Back 261

when all parts of a body move in the same direction as every other part

- in a straight line (rectilinear)
or
- in a curved line (curvilinear)

Front 262

How is movement of the entire human body generally described?

Back 262

as translation of the body's center of mass (or center of gravity)

(e.g., running forward would be anterior translation of COG)

Front 263

Active movement

Back 263

generated by stimulated or active muscle

Front 264

Passive movement

Back 264

generated by sources other than muscular activation such as gravity, resistance of a stretched ligament, push from another person, etc.

Front 265

Origin

Back 265

proximal attachment of a muscle or ligament

Front 266

Insertion

Back 266

distal attachment of a muscle or ligament

Front 267

Typical joint motions in the sagittal plane:

Back 267

- flexion
- extension
- dorsiflexion
- plantar flexion
- forward/backward bending

Front 268

Typical joint motions in the frontal/coronal plane:

Back 268

- abduction
- adduction
- lateral flexion
- ulnar and radial deviation
- inversion
- eversion

Front 269

Typical joint motions in the transverse/horizontal plane:

Back 269

- nearly all rotational movement
(internal, external rotation of shoulder, hip, trunk, etc.)

Front 270

What is an axis of rotation?

Back 270

(a.k.a. axis of movement)

pivot point about which joint motion occurs

always perpendicular to the plane of motion (e.g., flexion is in the sagittal plane, thus the axis of rotation is frontal/coronal)

Front 271

Motion in the sagittal plane occurs along the _____ axis of rotation.

Back 271

- frontal/coronal

(a.k.a. medial-lateral)

Front 272

Motion in the frontal/coronal plane occurs along the _____ axis of rotation.

Back 272

- sagittal

(a.k.a. anterior-posterior)

Front 273

Motion in the transverse/horizontal plane occurs along the _____ axis of rotation.

Back 273

- vertical

(a.k.a. longitudinal)

Front 274

How many possible degrees of freedom can a joint have?

Back 274

1, 2, or 3

Front 275

Degrees of freedom refers to:

Back 275

the number of planes of motion allowed at a joint

Front 276

What is internal rotation?

Back 276

anterior surface of bone rotates toward midline

Front 277

What is external rotation?

Back 277

anterior surface of bone rotates away from midline

Front 278

What is circumduction?

Back 278

circular motion through two planes (thus joint must have at least 2 degrees of freedom)

Front 279

What is protraction?

Back 279

translation of a bone away from the midline in a plane parallel to the ground

(generally used for scapula or jaw)

Front 280

What is retraction?

Back 280

movement of a bony segment toward the midline in a plane parallel to the ground

(generally used for scapula or jaw)

Front 281

What is horizontal adduction?

Back 281

usually refers to shoulder

with shoulder in abducted position (at 90 degrees), moving hands together in the horizontal plane

Front 282

What is horizontal abduction?

Back 282

usually refers to shoulder

with shoulder in abducted position (at 90 degrees), moving hands away from each other in the horizontal plane

Front 283

Benefits of closed-chain exercises:

Back 283

- more functional in nature
- capitalize on benefits of weight bearing

Front 284

Benefits of open-chain exercises:

Back 284

- increased ability to target specific muscle groups

- easily employable through use of weights or elastic bands/tubes

Front 285

In general, how do the articulating surfaces of joints work together?

Back 285

- generally the articular surfaces are curved
- one is convex
- one is concave

Front 286

What is joint congruency?

Back 286

fit

joints are stable due to the concave-convex workings of the articular surfaces

Front 287

Torque (rotational force) depends on:

Back 287

- amount of force
- distance between force and rotational axis (moment arm)

Front 288

Torque =

Back 288

force X moment arm

Front 289

Internal torque =

Back 289

muscular force X internal moment arm

Front 290

External torque =

Back 290

external force X external moment arm

Front 291

Two types of torque

Back 291

- internal torque

- external torque

Front 292

Movement of the body or a body segment is the result of:

Back 292

competition between internal and external torques about a joint

Front 293

Why are most of our bony lever systems in the body third-class levers?

Back 293

because it is usually essential that the distal ends of our limbs move faster than our muscles can physiologically contract

Front 294

Because most biomechanical lever systems in the body are third-class levers, most of the time a muscle must exert a force:

Back 294

greater than the load being lifted

Front 295

How do third-class levers affect joints?

Back 295

the joint must be able to tolerate the high forces generated and be able to disperse large muscular forces that are transferred through the articular and bony surfaces

this is the reason for articular cartilage, bursae, synovial fluid, etc.

Front 296

What is a muscle's line of pull?

Back 296

a.k.a. line of force

direction of muscular force, typically represented as a vector

Front 297

What does the relationship between a muscle's line of pull and the axis of rotation of a joint determine?

Back 297

the action or actions the muscle can produce

Front 298

Line of pull about a medial-lateral axis:
- anterior?
- posterior?

Back 298

- flexion in the sagittal plane

- extension in the sagittal plane

Front 299

Line of pull about a anterior-posterior axis:
- superior or lateral?
- inferior or medial?

Back 299

- abduction in the frontal/coronal plane

- adduction in the frontal/coronal plane

Front 300

Line of pull about a vertical/longitudinal axis:

Back 300

produces internal or external rotation

Front 301

With respect to the need for either force or speed/ROM with a given muscle/lever, the nervous system can:

Back 301

determine and activate the most efficient muscle for the job

Front 302

What is resultant force?

Back 302

the result produced by combining two individual force vectors

Front 303

If two force vectors are equal, what can be said of the resultant vector?

Back 303

it will be directed exactly between the middle of the two composite vectors

Front 304

If two force vectors are unequal (as is common in muscular forces) the resultant force and subsequent movement will be:

Back 304

distorted and pulled toward the stronger muscle

Front 305

Why are vectors important in kinesiology?

Back 305

- they help estimate the results of several muscles pulling in opposite directions

- they can also help assess movement for muscle weaknessess

(e.g., anterior and posterior deltoids have opposite directions of pull, but nearly equal force potential; if one is damaged and the other compensates, the clinician could see the pull toward the stronger muscle; helps us see asymmetry in movement and helps us correct it)

Front 306

Active motions of the body, powered by muscles, are determined by:

Back 306

the muscle's line of pull relative to the axis of rotation of a joint

Front 307

What factors determine the available motion (degrees of freedom) of a limb or body segment?

Back 307

- arthrokinematics (roll, slide spin)
- bony conformation
- ligamentous support

Front 308

Cortical bone

Back 308

compact bone

the dense tissue comprising the outermost portions of bones

Front 309

Cancellous bone

Back 309

spongy bone

the porous tissue comprising the inner portions of a bone

Front 310

What is the importance of cancellous bone structure?

Back 310

- it serves to lighten the bones, and
- it redirects forces toward weight-bearing surfaces covered with articular cartilage (like a series of mechanical struts)

Front 311

Diaphysis

Back 311

central shaft of bone

Front 312

Epiphyses

Back 312

the expanded portions of bone arising from the diaphysis

Front 313

Periosteum

Back 313

- thin, tough membrane covering each long bone

- highly vascularized
- highly innervated

- helps secure attachments of muscles and ligaments to bone

Front 314

Medullary canal

Back 314

- central hollow tube within the diaphysis of a long bone

- stores bone marrow

- provides passageway for nutrient-carrying arteries

Front 315

Endosteum

Back 315

- membrane that lines surface of medullary canal

- contains cells important for forming and repairing bone

Front 316

Classification of bones (5 basic categories)

Back 316

- long
- short
- flat
- irregular
- sesamoid

Front 317

What bone classification comprises the majority of the appendicular skeleton?

Back 317

long bones

Front 318

Description of short bones

Back 318

generally equal in length, width, and height

(e.g., carpal bones)

Front 319

Description of flat bones

Back 319

- generally flat or slightly curved

- often provide wide base for expansive muscular attachment

Front 320

Description of irregular bones

Back 320

wide variety of shapes and sizes

(e.g., vertebrae, facial bones)

Front 321

Description of sesamoid bones

Back 321

- subcategory of irregular bones

- encased within tendons

- protect tendon and increase muscle's leverage

Front 322

Largest sesamoid bone in the body

Back 322

patella

(embedded within tendon of quadriceps muscle to increase internal moment arm and thus torque production of the quadriceps)

Front 323

Primary function of synarthroses?

Back 323

- firmly bind bones together

- transmit forces from one bone to another

Front 324

Three classifications of joints in the body:

Back 324

- synarthrosis
- amphiarthrosis
- diarthrosis

Front 325

Three types of biologic material comprising joints

Back 325

- fibers
- ground substance
- cells

Front 326

Three types of fibers comprising connective tissues of joints

Back 326

- type I collagen
- type II collagen
- elastin

Front 327

Description of type I collagen

Back 327

- thick and rugged
- resists elongation
- composes ligaments, tendons, fibrous capsules

Front 328

Description of type II collagen

Back 328

- thinner and less stiff than type I
- provides flexible woven framework for maintaining shape and consistency of structures like hyaline cartilage

Front 329

Description of elastin

Back 329

- elastic
- resist stretching (tensile) forces
- have more "give" when elongated
- help prevent injury by allowing tissue to bend a great deal before breaking

Front 330

What is ground substance? ***

Back 330

- a water-saturated matrix composed primarily of glycosaminoglycans (gags), water, and solutes

- collagen and elastin fibers are embedded within it

- allows body fibers to exist in a fluid-filled environment, dispersing repetitive forces

Front 331

What are joint reaction forces?

Back 331

muscle contractions that occur with activity and whose energy must be transferred across the surfaces of our joints to stabilize our limbs

Front 332

How does healthy articular cartilage affect the joint?

Back 332

- it can more effectively dampen or absorb forces

- it also increases the surface area at the joint, thus reducing the stress on the cartilage

Front 333

What effects can severe arthritis have on joints in addition to inflammation and pain?

Back 333

- reduced ROM
- weaken soft tissues that stabilize the joint, over time potentially causing dislocation or subluxation

Front 334

Cells within connective tissues of joints are primarily responsible for the _______ and ______ of tissues that constitute joints

Back 334

maintenance, repair

Front 335

Four basic types of connective tissue:

Back 335

- dense irregular connective tissue
- articular cartilage
- fibrocartilage
- bone

Front 336

Is the fibrous composition of tendons and ligaments similar?

Back 336

yes, except that the arrangement of the fibers differs

(tendon fibers tend to lie in parallel bundles to better transmit muscular force, while ligament fibers are irregularly aligned and cross to accept tensile forces)

Front 337

Why are tendon fibers aligned in a parallel fashion?

Back 337

to allow muscular force to be efficiently transmitted to bone with minimal loss of muscle energy

Front 338

Why are ligament fibers aligned in an irregular crossing pattern?

Back 338

to allow it to accept tensile forces from several different directions while maintaining the integrity of the joint

Front 339

What provides the majority of static stability to a joint?

Back 339

- bony conformation

- ligamentous networks

Front 340

What provides dynamic stability to a joint?

Back 340

muscles functioning as active stabilizers

Front 341

Many rehabilitation programs are designed to strengthen the supporting musculature in an effort to...

Back 341

stabilize the joint in which the passive stabilizing structures such as ligaments are insufficient

Front 342

Persons with advanced age and those with long-term immobilization of joints display what three common changes in the connective tissue surrounding joints?

Back 342

- tissue weakness
- tissue dehydration
- tissue stiffness

Front 343

How do clinicians attempt to prevent the tissue weakness, tissue stiffness, tissue dehydration cycle from beginning?

Back 343

- early return to weight bearing
- AROM, PROM
- functional exercise
- patient education

Front 344

What is the sole producer of active force in the body? ***

Back 344

muscle

Front 345

How does muscle create movement? ***

Back 345

it is stimulated by the nervous system, contracts, and pulls on bone to create movement

Front 346

What moves when a muscle contracts? ***

Back 346

the freest (or least-constrained) segment

Front 347

Of what two types of material is skeletal muscle composed? ***

Back 347

- muscle tissue (contractile)

- connective tissue

Front 348

Three characteristics of contractile muscle tissue ***

Back 348

- elasticity
- contractility
- irritability

Front 349

What is elasticity with respect to contractile muscle tissue? ***

Back 349

ability to resist shearing forces and to return to original form after being stretched

Front 350

What is contractility with respect to contractile muscle tissue? ***

Back 350

ability to develop tension against resistance

Front 351

What is irritability with respect to contractile muscle tissue? ***

Back 351

ability to respond to chemical, electrical, or mechanical stimuli

Front 352

Characteristics of muscular connective tissue ***

Back 352

- surrounds and supports muscle tissue in form of sheaths, fascia, aponeuroses

- all interconnected and continues the passive elastic component of a muscle

- non contractile

Front 353

Muscle cell =

Back 353

muscle fiber

Front 354

Muscle fibers contain ______, which contains myofibrils. ***

Back 354

sarcoplasm

Front 355

Of what are myofibrils composed? ***

Back 355

of many tiny filaments = myofilaments

Front 356

Of what are myofilaments composed? ***

Back 356

of proteins
- actin and
- myosin

Front 357

Segments of myofibrils are divided into _______, which contain actin and myosin filaments. ***

Back 357

sarcomeres

Front 358

What is a sarcomere? ***

Back 358

the contractile unit of muscle wherein actin and myosin move over each other (form cross bridges) in response to a stimulus

Front 359

What generates active tension in muscle tissue? ***

Back 359

formation of actin-myosin cross bridges

Front 360

How does one increase the number of muscle fibers in the body? ***

Back 360

- you can't

- individuals are born with a set number of muscle fibers

Front 361

What effect do strengthening exercises have on muscles? ****

Back 361

they increase the number of sarcomeres, which increases muscle fiber size

does NOT increase the number of muscle fibers

Front 362

What is a motor unit? ***

Back 362

the alpha motor neuron and all the muscle fibers it innervates

(multiple motor units per muscle)

Front 363

Motor units fire ________ within the muscle. ****

Back 363

asynchronously

Front 364

The more motor units firing in muscle, the...

Back 364

greater the tension generated

(the nervous system only activates the number of motor units needed for the job being done)

Front 365

The number of motor units varies from muscle to muscle.

Which have more? Less? ***

Back 365

- fine motor muscles

- gross motor muscles

Front 366

Motor units in fine motor muscles ***

Back 366

fine motor muscles (eye, fingers) have lots of motor units with fewer muscle fibers per motor unit

Front 367

Motor units in gross motor muscles ***

Back 367

gross motor muscles (legs, trunk) have fewer motor units with many muscle fibers per motor unit

Front 368

On average, how many muscle fibers are controlled by a single motor neuron in the human body? ***

Back 368

80-100

Front 369

What is a muscle's origin? ***

Back 369

- proximal attachment

- point of attachment closest to the midline or “core” of the body in the anatomic position

(also explained as the fixed/non-moving point)

Front 370

What is a muscle's insertion? ***

Back 370

- distal attachment

- point of attachment farthest from the midline or body “core”

(also explained as the moving portion)

Front 371

What are the three types of principle muscle fibers found in skeletal muscle? ***

Back 371

- slow-twitch oxidative (SO) type I fibers

- fast-twitch glycolytic (FG) type II fibers

- fast-twitch oxidative glycolytic (FOG) type IIA fibers

Front 372

Characteristics of fast-twitch glycolytic (FG) type II fibers ***

Back 372

- fast speed of contraction; fast rate of fatigue
- muscles with a high percentage of these fibers are able to respond rapidly to stimulus and produce large ROM
- large diameter fibers
- sparse capillarity

- for mobility, no postural muscles (biceps)

Front 373

Characteristics of fast-twitch oxidative glycolytic (FOG) type IIA fibers ***

Back 373

- fast speed of contraction; intermediate rate of fatigue

- intermediate diameter fibers with dense capillarity

Front 374

Characteristics of slow-twitch oxidative (SO) type I fibers ***

Back 374

- slow speed of contraction; slow rate of fatigue
- small diameter fibers; dense capillarity

- muscles with a high percentage of these fibers are able to carry on sustained activity
- primarily involved in stability, postural muscles (e.g., soleus)

Front 375

Are muscles made up solely of one type of fiber? ***

Back 375

- all types of muscle fibers exist in all muscle but percentages vary muscle to muscle and individual to individual

- composition is genetically determined:
(e.g., a world-class sprinter will likely have a higher percentage of FG fibers in lower extremity muscles, while a world-class marathoner will likely have a higher percentage of SO fibers in lower extremity muscles)

Front 376

What three factors determine the functional potential of a muscle? ***

Back 376

- cross-sectional area (how big/how many fibers?)
- shape
- line of pull

Front 377

What is the cross-sectional area of a muscle, and of what is it an indirect measure? ***

Back 377

- cross-sectional area is a measure of the thickness of a muscle

- it is an indirect measure of contractile elements available to generate force

Front 378

The larger a muscle's cross-sectional area, the greater:
***

Back 378

its force potential

(i.e., a person with larger muscles can usually generate larger muscular forces)

Front 379

Muscle shape is one important indicator of: ***

Back 379

a muscle's specific action

Front 380

Most muscles are of what four shapes? ***

Back 380

- fusiform
- triangular
- rhomboidal
- pennate

Front 381

Description of a fusiform muscle? ***

Back 381

- fibers run parallel to one another

- built to provide large ranges of motion

(e.g., biceps brachii)

Front 382

Description of a triangular muscle? ***

Back 382

- expansive proximal attachments converging to a small distal attachment

- provide a stabilized base for generating force

(e.g., gluteus medius)

Front 383

Description of a rhomboidal muscle? ***

Back 383

- expansive proximal and distal attachments

-shaped like large rhomboids or off-set squares

- suited to stabilize a joint or provide large forces, depending on cross-sectional area

(e.g., gluteus maximus)

Front 384

Description of pennate muscles. ***

Back 384

- shape resembles a feather
- muscle fibers approach a central tendon at an oblique angle

- large force potential
- limited excursion (range)

- further classified as unipennate, bipennate, or multipennate, based on number of fiber sets attached to central tendon

Front 385

Muscle forces can be described as vectors because.... ***

Back 385

they possess both a direction and a magnitude

Front 386

Direction of a muscle's force is referred to as: ***

Back 386

line of pull

(or line of force)

(e.g., a muscle's line of pull that courses anterior to the medial-lateral axis of rotation of the shoulder performs flexion; if it coursed posterior it would perform extension)

Front 387

What is the length-tension relationship of a muscle? ***

Back 387

- the degree to which muscle is either stretched or shortened at the time of its activation

- it significantly impacts force output of muscle

- the concept that muscle length strongly influences muscle force influences many clinical activities
(e.g., testing and strengthening of muscles)

Front 388

How is the concept of the length-tension relationship of a muscle useful in clinical activities? ***

Back 388

- it is known that muscle length strongly influences muscle force

- this carries over into activities for testing and strengthening muscles

Front 389

Force generated within a muscle by an active length-tension relationship is highly dependent upon _____ length. ***

Back 389

sarcomere

Front 390

Where is a muscle's active force generally greatest? ***

Back 390

at its midlength

Front 391

Where is a muscle's active force generally least? ***

Back 391

at both extremes

Front 392

How is force generated within a muscle by a passive length-tension relationship? ***

Back 392

because of their elasticity, muscles also produce force passively

Front 393

When do muscles generate greater internal elastic force? ***

Back 393

when stretched

Front 394

What does a muscle's passive length-tension curve demonstrate? ***

Back 394

its elastic behavior

Front 395

How does the velocity of a concentric muscular contraction affect force production? ***

Back 395

- during a concentric contraction, a muscle produces less force as the speed of contraction increases

- at higher speeds of contraction, the actin-myosin cross bridges lack sufficient time to form, pull, and re-form; therefore force is decreased

Front 396

Describe the force created by an isometric muscular contraction. ***

Back 396

it creates a greater force than any speed concentric contraction

Front 397

Describe the force production of an eccentric muscular contraction. ***

Back 397

force production increases slightly as the speed of the elongation increases

Front 398

Describe parallel muscle fiber arrangements. ***

Back 398

- a.k.a. fusiform
- bundles of long fibers that run parallel to axis of muscle
- produce greater ROM of bony lever

(e.g., biceps brachii, SCM, rectus abdominis)

Front 399

Describe oblique muscle fiber arrangements. ***

Back 399

- a.k.a. pennate
- bundles of short muscle fibers, oblique to axis of muscle
- produce greater force/stability

(e.g., deltoid, rectus femoris)

Front 400

What is muscle tension? ***

Back 400

magnitude of the force of muscle, both active and passive

Front 401

What is active muscle tension? ***

Back 401

- developed by contractile elements of muscle (muscle contracting)

- motor unit is stimulated, sarcomere shortens

Front 402

How is active muscle tension increased? ***

Back 402

- increasing frequency of motor units firing

- increasing number of motor units fired

- increased cross sectional area of fiber (increased number of sarcomeres)

Front 403

Active muscle tension + passive muscle tension = ***

Back 403

total tension of muscle

Front 404

What is passive muscular tension? ***

Back 404

- force developed by passive elastic components of muscle (muscle stretching)

- the tension necessary for a muscle to contract or recoil

Front 405

An increase in muscle fiber size results in: ***

Back 405

an increase in tension output

(a result of resistive exercise, which increases muscle fiber size, NOT the number of muscle fibers)

Front 406

What is the muscle's length-tension relationship? ***

Back 406

- the optimal length at which the muscle is capable of developing its maximal tension

- if the muscle is shortened or lengthened beyond that length, the amount of tension the muscle is able to generate is decreased

Front 407

What is the muscle's optimal length with respect to the length-tension relationship? ***

Back 407

- slightly longer than normal resting length

(about 1.2 times longer)

Front 408

How does the body carry out moving muscles to the optimal length-tension ratio? ***

Back 408

- it is innate/subconscious

- the body automatically places the muscles at the proper length for optimal tension development

(e.g., when you go to kick a ball, you naturally extend your hip and flex your knee to "wind up" for the kick)

Front 409

How were the rubber bands related to muscles in the class activity? ***

Back 409

- passive tension = stretching of the rubber band

- active tension = release of the rubber band

Front 410

What is a concentric contraction? ***

Back 410

- muscle shortens
- muscle attachments move toward each other
- anti-gravity movement

Front 411

What is an eccentric contraction? ***

Back 411

- muscle lengthens
- muscle attachments move away from each other
- controlled movement into gravity
- muscle acts as a resistance to gravity's effort (2nd class lever)
( a "negative")

Front 412

What is an isometric contraction? ***

Back 412

- no change in muscle length

- no movement of joint

Front 413

Rank concentric, eccentric, and isometric contractions with respect to amount of muscle tension developed (least to most.) ***

Back 413

Least - concentric
Medium - isometric
Most - eccentric

Front 414

What is normal muscle action with respect to origin and insertion? ***

Back 414

- distal muscle attachment moves the free distal bony segment toward the fixed proximal bony segment

- insertion moves toward origin

Front 415

What is an agonist? ***

Back 415

- the prime mover

- the muscle or muscle group most directly related to performing a specific joint movement

Front 416

What is an antagonist? ***

Back 416

- a muscle or muscle group that can oppose the action or actions of the agonist

- performs opposite motion of agonist

- usually inhibited by the nervous system when the agonist is contracting (i.e., reciprocal inhibition)

- usually the antagonist passively elongates as the agonist actively contracts

Front 417

What is a prime mover? ***

Back 417

same as agonist

Front 418

What is reciprocal inhibition? ***

Back 418

inhibition of the antagonist when the agonist is contracting

Front 419

What is co-contraction? ***

Back 419

- agonist & antagonist contract simultaneously in an isometric fashion

- co-contractions around a joint provide stability to the joint

Front 420

What is a synergist? ***

Back 420

- muscle which assists the agonist in providing action

- can also stabilize the joint during action

- may neutralize unwanted motion (suppressing unwanted or refining desired motion)

Front 421

What is a stabilizer? ***

Back 421

muscle that “fixes” or holds a body segment relatively stationary so that another muscle can more effectively perform

Front 422

What is a force-couple? ***

Back 422

synergistic action occurring when muscles produce force in different linear directions but produce torque in the same rotary direction

(e.g., placing two hands on book, moving them in opposite directions--book rotates; similar motion seen in scapular rotation)

Front 423

Typically, a muscle can only shorten or elongate about ____ of its resting length (excursion). ***

Back 423

half

Front 424

What is active insufficiency? ***

Back 424

- diminished ability of a muscle to maintain/produce active tension (weak muscle)

- muscle is maximally shortened prior to FROM across all involved joints

- when a muscle reaches a point where it cannot shorten any farther it is has reached active insufficiency

- a muscle becomes actively insufficient at the end of the range of motion that it produces

- deals with 2-joint muscles

(e.g., hamstrings exhibit active insufficiency when simultaneously extending hip and flexing knee; FROM cannot be achieved at both joints---a.k.a. putting a muscle "on slack.")

Front 425

What is passive insufficiency? ***

Back 425

- insufficient (antagonist) muscle length to permit FROM to be produced simultaneously at all joints crossed by muscle

- the inability of a muscle that spans two or more joints to be stretched sufficiently to produce a full range of motion in all the joints simultaneously

- deals with 2-joint muscles

[e.g., long finger flexor muscles become passively insufficient as they are stretched over wrist and finger joints during wrist extension. Passive tension developed in finger flexors causes finger to flex. (“Putting them on stretch.”)]

Front 426

Name two sensory receptors associated with muscle tissue. ***

Back 426

- golgi tendon organs

- muscle spindles

Front 427

What is a Golgi tendon organ? ***

Back 427

- located in musculotendinous junction

- respond to tension caused by excessive muscle contraction

- response: agonist is inhibited, antagonist is facilitated (opposing muscle kicks in)

Front 428

What is a muscle spindle? ***

Back 428

- located throughout muscle belly
- respond to muscle stretching
- response: facilitate muscle contraction

Front 429

How do muscles serve a mobility function for the body? ***

Back 429

by producing/controlling movement of bony levers around joint axes

Front 430

How do muscles serve a stability function for the body? ***

Back 430

by resisting movement of joint surfaces and through approximation of joint surfaces

Front 431

What is a shunt muscle? ***

Back 431

- muscles that have proximal attachments close to the joint axis with the distal attachment far away from joint axis

- muscles that maintain joint stability by compression

(e.g., brachioradialis)

Front 432

What is a spurt muscle? ***

Back 432

- muscles that have proximal attachments far from the joint axis with the distal attachment close to the joint axis

- muscles that create large rotatory component (ROM)

(e.g., biceps brachii)

Front 433

Give three examples of how variation in muscle design affects stability/mobility. ***

Back 433

- fiber composition
(e.g., higher percentage of SO fibers = more power; higher percentage of FG fibers = more speed)

- fiber arrangement
(e.g., oblique fiber arrangement = more power; parallel fiber arrangement = more ROM/speed)

- fiber location
(e.g., deep fibers = more power; superficial fibers = more speed)

Front 434

What happens to muscle tissue during periods of immobility? ***

Back 434

- overall tension-generating capacity is decreased secondary to immobilization in either shortened or lengthened position*
- increase in connective tissue results in increased stiffness to passive stretch
- increased fatigability of muscle
- muscle atrophy

*recovery of muscle from immobilization in shortened position takes a longer time to recover from than immobilization in a lengthened position

Front 435

Characteristics of muscular injuries (due to overuse). ***

Back 435

- overuse injuries (repetitive trauma that does not allow for complete tissue repair)

- musculotendinous unit most often affected

- microtrauma, then inflammation, edema, connective tissue thickening, and secondary scar tissue/adhesions

- may enter plastic stage (elasticity gone) which can lead to tissue failure

Front 436

How does aging affect muscle tissues? ***

Back 436

- increase of connective tissue within the muscle leads to muscle stiffness

- studies show that resistive exercise results in increased strength levels with elderly

Front 437

How can muscles work as active stabilizers? ***

Back 437

- although ligaments and capsules can stabilize joints, only muscle can adapt to the immediate and long-term external forces that can destabilize the body

- many types of injuries such as ligamentous rupture can significantly destabilize a joint

- physical therapists and physical therapist assistants often improve stability of a joint by strengthening the surrounding muscles

Front 438

Besides producing all active motions, muscles also:

Back 438

control and stabilize our posture by their action at joints

Front 439

How do clinicians help patients compensate for structures like ligaments that have been weakened by disease or trauma?

Back 439

by helping patients strengthen muscles to stabilize the underlying joints

Front 440

When a muscle contracts, the _____ kinematic segment moves.

Back 440

freest (or least constrained)

that may produce an open chain motion (e.g., knee extension) or closed chain (e.g., rising from a chair)

Front 441

Once stimulated, muscles react by producing a _____ or _____ force.

Back 441

contractile or pulling

NEVER pushing!

Front 442

An active muscle develops a force in only one of three ways. Name them.

Back 442

- concentric = shortening (or contracting)
- eccentric = attempting to resist elongation (a "negative")
- isometric = remaining at a constant length

Front 443

What is a concentric activation?

Back 443

- muscle produces active force and simultaneously shortens

- muscle decreases distance between proximal and distal attachments

- internal torque produced by the muscle exceeds the external torque produced by an outside force

Front 444

What is an eccentric activation?

Back 444

- muscle produces an active force (attempts to contract) but is simultaneously pulled to a longer length by a more dominant external force

- external torque (often due to gravity) exceeds internal torque produced by the muscle

- muscle is lengthened in a controlled manner (e.g., like a "negative", lowering oneself into a chair, lowering an arm, etc.)

Front 445

If an action is "lowering," it is almost 100% certain the muscles controlling the action are ______ activated.

Back 445

eccentrically

Front 446

During an eccentric activation, _______ usually powers the movement, but the eccentric activation of muscle is used to decelerate the rate of descent.

Back 446

gravity

Front 447

What is isometric activation?

Back 447

- occurs when a muscle generates an active force while remaining at a constant length

- muscle generates internal torque equal to the external torque

- no motion or change in joint angle

Front 448

Proximal attachment = ______

Back 448

origin

Front 449

Distal attachment = ______

Back 449

insertion

Front 450

What is the proximal attachment/origin?

Back 450

the point of attachment that is closest to the midline, or core, of the body when in the anatomic position

Front 451

What is the distal attachment/insertion?

Back 451

the point of attachment that is farthest from the midline, or core, of the body

Front 452

How can an overly stiff antagonist muscle affect movement?

Back 452

by limited ROM in passively elongating, it prevents the agonist from fully contracting

Front 453

What is a co-contraction?

Back 453

- occurs when agonist and antagonist are simultaneously activated in a pure or near isometric fashion

- often stabilize (and therefore protect) joints

Front 454

What are synergists?

Back 454

muscles that work together to perform a particular action

Front 455

Most meaningful movements of the body involve.....

Back 455

the synergistic action of muscles

Front 456

What is a force-couple?

Back 456

a type of synergistic action that occurs when two or more muscles produce force in different linear directions but produce torque in the same rotary direction (e.g., scapular rotation)

Front 457

What is excursion?

Back 457

change in the length of a muscle

(lengthening OR shortening)

Front 458

Name the three main components of a muscle, and the type of connective tissue surrounding each.

Back 458

muscle belly - epimysium
fascicle - perimysium
muscle fiber/cell - endomysium

Front 459

What is a sarcomere?

Back 459

the basic contractile unit of a muscle fiber/cell

Front 460

Each sarcomere is composed of:

Back 460

two main protein filaments, actin and myosin

Front 461

What are actin and myosin?

Back 461

the two main protein filaments comprising a sarcomere

Front 462

What is the sliding filament theory?

Back 462

states that active force within a muscle is generated as actin filaments slide past the myosin filaments, resulting in the contraction of an individual sarcomere

Front 463

Which is the thick filament in a sarcomere? The thin filament?

Back 463

- myosin

- actin

Front 464

What is an actin-myosin cross bridge?

Back 464

the connection made when the heads on the thick myosin filament attach to the thin actin filament

Front 465

What is a power stroke?

Back 465

occurs when the myosin head binds to the actin filament then flexes

this slides the actin filament past the myosin, generating force and shortening the sarcomere

Front 466

How does the shortening of sarcomeres affect the entire muscle?

Back 466

because the sarcomeres are joined end to end throughout an entire myofibril,

and the myofibrils are bound by endomysium into a muscle fiber/cell,

which, in turn are bound by perimysium into fascicles, and finally by epimysium into muscle bellies,

the shortening of the sarcomeres shortens the whole (by up to half)

Front 467

Why is the number of myosin heads and actin binding sites important?

Back 467

in order for the sarcomere to maximally contract, numerous power strokes must occur

more cross-bridges = more power strokes = more power

Front 468

The force of a muscular contraction is determined largely by:

Back 468

the number of actin-myosin cross-bridges that are formed

Front 469

What is a muscle belly?

Back 469

the bulk, or body of the muscle

Front 470

Of what are muscle bellies comprised?

Back 470

fasciculi (fascicles)

Front 471

What connective tissue surrounds muscle bellies, and what is its purpose?

Back 471

epimysium

to surround the outer layer (belly) of the muscle and hold its shape

Front 472

What is a fascicle?

Back 472

a bundle of muscle fibers

Front 473

What connective tissue surrounds fasciculi, and what is its function?

Back 473

perimysium

to support the fasciculi and serves as a vehicle to support the nerves and blood vessels

Front 474

What is a muscle fiber/cell?

Back 474

an individual cell with multiple nuclei

Front 475

What is contained within a muscle fiber/cell?

Back 475

all the contractile elements within muscle

myofibrils comprised of myofilaments

Front 476

What connective tissue surrounds each muscle fiber/cell and what is its purpose?

Back 476

endomysium, a dense meshwork of collagen fibrils

it helps transfer contractile force to the tendon

Front 477

What is a myofibril?

Back 477

the contractile elements of the muscle fiber/cell

sarcomeres and contractile proteins

Front 478

What is the physiologic cross-sectional area of a muscle?

Back 478

its thickness--an indirect and relative measure of the amount of contractile elements available to generate force

Front 479

The larger a muscle's cross-sectional area:

Back 479

the greater its force potential

Front 480

Troponin is responsible for:

Back 480

exposing the actin filament to the myosin head and allowing cross-bridge formation

Front 481

In general, a maximally activated muscle produces approximately ___ pounds of force for every square inch of muscular tissue.

Back 481

50

(this is fairly standard and varies little among different people or different muscles)

Front 482

A muscle's shape is one important indicator of:

Back 482

its specific action

Front 483

Long, strap-like muscles typically provide:

Back 483

large ranges of motion

Front 484

Thick, short muscles typically provide:

Back 484

large forces

Front 485

Four basic muscle shapes

Back 485

- fusiform
- triangular
- rhomboidal
- pennate

Front 486

Characteristics of fusiform muscles

Back 486

- parallel fibers

- large ranges of motion

Front 487

Characteristics of triangular muscles

Back 487

- expansive proximal attachments that converge to a small distal attachment

- large proximal attachments provide a well-stabilized base for generating force

Front 488

Characteristics of rhomboidal muscles

Back 488

- expansive proximal and distal attachments

- generally shaped like large rhomboids or offset squares

- expansive attachments make them well suited to stabilize a joint or provide large forces (depending on the cross-sectional area)

Front 489

Characteristics of pennate muscles

Back 489

- shape of a feather

- muscle fibers attach to central tendon at an oblique angle

- diagonal orientation maximizes force potential (more muscle fibers fit into the muscle compared to a similar-sized fusiform muscle, but the angle also limits their excursion, so less ROM)

- often found in muscles that are required to produce large forces to support or propel the weight of the body

Front 490

How are pennate muscles classified?

Back 490

- unipennate - fibers attach to one side of central tendon
- bipennate - fibers attach to both sides of central tendon
- multipennate - fibers attach to multiple sides of central tendon

Front 491

Muscle forces can be described as a vector, because they possess both ______ and _______.

Back 491

direction

magnitude

Front 492

The direction of a muscle's force is referred to as the muscle's....

Back 492

line of pull (or line of force)

Front 493

A muscle's line of pull is assumed....

Back 493

to act in a straight line

Front 494

A muscle's line of pull relative to the axis of rotation of a joint dictates....

Back 494

the muscle's action

Front 495

What is the operational length of a muscle?

Back 495

the degree to which a muscle is stretched or shortened at the time of its activation

(a.k.a. length-tension relationship)

Front 496

The length-tension relationship has a significant impact on the _____ _____ of muscle.

Back 496

force output

Front 497

Muscle length strongly influences muscle ______.

Back 497

force

Front 498

Length is critical in the active length-tension relationship because....

Back 498

length determines the number of effective actin-myosin cross-bridges that exist at any given time

more cross-bridges = more contraction force

(e.g., men pulling cart analogy on page 43)

Front 499

Because of their elastic nature, muscles also produce force _____.

Back 499

passively

Front 500

What is the passive length-tension relationship?

Back 500

due to their elastic nature, muscles produce force passively, generating internal elastic force when stretched (like a rubber band)

Front 501

How do we innately use the passive length-tension relationship?

Back 501

"loading before exploding"

we wind up to kick a ball, squat down before we jump, do plyometrics, etc.

Front 502

What is a mono-articular muscle? A multi-articular (or poly-articular) joint?

Back 502

- crosses only one joint

- crosses multiple joints

Front 503

Which type of muscle can be stretched to a greater degree, mono- or multi-articular?

Back 503

multi-articular

Front 504

Describe how the multi-articular biceps can maintain near-constant (and optimal) overall length during activity.

Back 504

e.g., when pulling an object toward you, the elbow flexes (biceps contraction) but the shoulder simultaneously extends (biceps elongates)

this helps produce a more constant force throughout the ROM

this strategy of balance is important to remember when designing functional exercises or teaching functional activities that involve activation of multi-articular muscles

Front 505

How does velocity of a muscular contraction impact force production in a concentric contraction?

Back 505

as speed of contraction increases, less force is produced because the actin-myosin cross-bridges do not have time to form (pull) and reform

Front 506

How does velocity of a muscular contraction impact force production in an isometric contraction?

Back 506

since the velocity of an isometric contraction is zero, nearly all the actin-myosin cross-bridges are formed and all are given enough time to reach their maximal force-producing potential

isometric activation of a muscle creates greater force than any speed concentric contraction

Front 507

How does velocity of a muscular contraction impact force production in an eccentric contraction?

Back 507

force production increases slightly as the speed of the elongation increases, partly because of the elasticity of the connective tissues within the muscle

resistance to elongation increases with increased speed of elongation

Front 508

Because multi-articular muscles can experience extreme shortening or elongation across multiple joints, they are often associated with _______ ________.

Back 508

functional weakness

Front 509

Example of passive insufficiency

Back 509

fully flex wrists and try to make a fist

passive insufficiency of the antagonist

passive insufficiency or excessive tightness in the over-stretched long finger extensor muscles prevents making a fist

Front 510

Example of active insufficiency

Back 510

fully flex wrists and try to make a fist

active insufficiency of the agonist

long finger flexor muscles were too short (slackened) over the flexed wrist and flexed fingers

(put "on slack")

Front 511

What principle is often used therapeutically to isolate certain muscles?

Back 511

active insufficiency

put the muscle "on slack" (i.e., make it too short to produce force/contract)

Front 512

Force-velocity relationship and reasoning for it for a concentric muscle activation

Back 512

slower-speed contraction produces greater force

more time for actin-myosin cross-bridge formation

Front 513

Force-velocity relationship and reasoning for it for a eccentric muscle activation

Back 513

higher-speed elongation produces greater force

stretching of passive elements of muscle

Front 514

Force-velocity relationship and reasoning for it for an isometric muscle activation

Back 514

force is greater than any speed concentric contraction

velocity is zero, allowing maximal cross-bridge formation

Front 515

Muscles will often adapt to the length at which....

Back 515

they are most often held

held in a shortened position, muscles shorten,
held in an elongated position, muscles lengthen

Front 516

What often causes adaptive shortening in muscle?

Back 516

- disease
- immobility
- poor posture

Front 517

What is a contracture?

Back 517

a muscle so tight that it severely restricts joint movement

Front 518

Overly tight muscles cause the associated joints to....

Back 518

assume a posture that mimics the muscle's primary actions

(if hamstring is tight, the hip will extend and the knee will flex; therapist needs to produce the opposite)

Front 519

Optimal stretching of a muscle requires:

Back 519

the therapist to hold a limb in a position that is opposite to all of the muscle's actions

Front 520

What are some guidelines for proper stretching?

Back 520

- position the joint(s) in a manner opposite to all of the tightened muscle's normal actions

- hold at least 20-30 seconds
- stretch frequently

- maintain some stretch throughout the day
- strengthen the antagonists
- do not over-stretch

Front 521

What is muscular atrophy?

Back 521

muscle wasting or decrease in muscle mass, with the proportional loss in muscle strength

Front 522

Muscular weakness can significantly impair the ability to perform normal functional activities and may result in:

Back 522

- postural abnormalities

- injury to joints

Front 523

What two principles should be considered when designing an exercise program?

Back 523

- overload principle

- training specificity principle

Front 524

What is the overload principle?

Back 524

a principle that states a muscle must receive sufficient level of resistance to stimulate hypertrophy and strength increase

(sufficient to cause hypertrophy but not injury!)

Front 525

What is the training specificity principle?

Back 525

states that a muscle will adapt to the way in which it is challenged

therefore clinicians attempt to design exercises that match the natural demands placed on the muscle

Front 526

What is muscular hypertrophy?

Back 526

muscular growth or enlargement that indicates an increase in strength

Front 527

What causes muscular hypertrophy?

Back 527

an increase in the size of individual muscle fibers, NOT an increase in the number of fibers

increase is due to the synthesis of more proteins involved with muscle force (i.e., actin and myosin) thus enabling more cross-bridges to form and greater maximal force

Front 528

Why is muscle tissue ideally suited to stabilize a joint?

Back 528

because it is coupled to both
- external environment, and
- internal control mechanisms of the nervous system

Front 529

The force generated by muscle is the primary means by which an individual controls the intricate balance between

Back 529

- stable posture
and
- active movement

Front 530

Which of the following statements describes a concentric contraction? ***

a. The proximal and distal attachments of the muscle become farther apart.
b. The proximal and distal attachments of the muscle become closer together
c. The internal torque produced by the muscle is greater than the external torque produced by an outside force.
d. A and C
e. B and C

Back 530

e. B and C

Front 531

Which of the following types of muscular activation results in elongation of the muscle? ***

a. concentric
b. eccentric
c. isometric

Back 531

b. eccentric

Front 532

Which of the following statements best describes an antagonist? ***

a. A muscle that fixes or holds a body segment stationary so that another muscle can more effectively perform an action
b. a muscle that always shortens when it is active
c. a muscle or muscle group that opposes the action of an agonist
d. the muscle or muscle group most directly responsible for performing a particular action

Back 532

c. a muscle or muscle group that opposes the action of an agonist

Front 533

Which of the following statements best describes a muscular force-couple? ***

a. two or more muscles actively lengthening throughout an entire action
b. combined agonist and antagonist activity resulting in no or minimal joint movement
c. when two or more muscles produce force in different linear directions but produce rotary torque in the same linear direction
d. when an overly stiff or tight antagonist limits the action of the agonist muscle

Back 533

c. when two or more muscles produce force in different linear directions but produce rotary torque in the same linear direction

Front 534

Which of the following statements is true? ***

a. the larger a muscle's cross-sectional area, the greater its force-producing potential
b. in pennate muscles, nearly all the muscle fibers run parallel to one another
c. a muscle is able to produce the most force as it nears a maximally shortened position
d. a and b
e. a and c

Back 534

a. the larger a muscle's cross-sectional area, the greater its force-producing potential

Front 535

A muscle with a line of pull anterior to the medial-lateral axis of rotation of the shoulder will perform: ***

a. abduction
b. flexion
c. adduction
d. extension

Back 535

b. flexion

Front 536

The primary reason a muscle can produce the most force near its midrange is: ***

a. elastic properties of muscle help add to the active force of a muscle in its midrange
b. minimal actin-myosin cross-bridge formation is available in a muscle's midrange
c. passive elements of muscular tissue are put "on slack"
d. the number of actin-myosin cross-bridges that can be formed is near maximal

Back 536

d. the number of actin-myosin cross-bridges that can be formed is near maximal

Front 537

Which of the following statements is (are) true? ***

a. the passive length-tension curve indicates that muscle produces more passive force when it is stretched, rather than slackened
b. the force a muscle produces during a concentric contraction increases as the velocity of the contraction increases
c. the force produced by a muscle activated isometrically is greater than any speed of concentric contraction
d. A and C
e. B and C

Back 537

d. A and C

Front 538

The term "active insufficiency" describes: ***

a. a muscle's inability to perform an action because of the tightness of its antagonist
b. decreased ability of a two-joint (multi-articular) muscle to produce significant force to complete an action because it has become too short
c. the inability of an action to be completed because the antagonist is stretched over multiple joints
d. when two or more muscles combine forces but fail to complete an action

Back 538

b. decreased ability of a two-joint (multi-articular) muscle to produce significant force to complete an action because it has become too short

Front 539

If a muscle that performs both hip flexion and knee extension becomes tight, which of the following combination of actions will likely be limited? ***

a. hip flexion and knee extension
b. hip extension and knee flexion
c. hip flexion and knee flexion
d. hip extension and knee extension

Back 539

b. hip extension and knee flexion

Front 540

During a concentric contraction, the muscle is active and shortening. ***

a. true
b. false

Back 540

a. true

Front 541

According to the sliding filament theory, contraction of a sarcomere is the result of actin filaments sliding past myosin filaments. ***

a. true
b. false

Back 541

a. true

Front 542

Isometric activation of muscle results in the proximal and distal attachments of a muscle becoming farther apart. ***

a. true
b. false

Back 542

b. false (they do not move)

Front 543

Regardless of whether a muscle is lengthening or shortening, a muscle can produce only a contractile, or pulling force. ***

a. true
b. false

Back 543

a. true

Front 544

A muscle's "excursion" refers to the maximal force that the muscle can produce. ***

a. true
b. false

Back 544

b. false (change in length)

Front 545

A "multi-articular" muscle refers to a muscle that crosses two or more joints. ***

a. true
b. false

Back 545

a. true

Front 546

Fusiform muscles can typically produce more force than similar-sized pennate muscles. ***

a. true
b. false

Back 546

b. false (the opposite is true)

Front 547

The overload principle states that a muscle must receive a sufficient amount of resistance to stimulate hypertrophy. ***

a. true
b. false

Back 547

a. true

Front 548

"Atrophy" refers to muscular enlargement or an increase in muscle mass. ***

a. true
b. false

Back 548

b. false (wasting or decrease in muscle mass)

Front 549

In order to stretch or maximally elongate a muscle, the muscle must be placed in a position opposite that of all its actions. ***

a. true
b. false

Back 549

a. true