Biomechanics/Kines Midterm Flashcards

1
Q

kinematics

A

ROM
strength
speed
no regard to forces or torques
measured by goniometer and accelerator

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2
Q

kinetics

A

forces
torques
muscle/joint interaction
effect of forces and torques on body
measured by transducer

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3
Q

bones rotate around a plane that is…

A

… perpendicular to an axis of rotation

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4
Q

degrees of freedom

A

number of independent directions of movement allowed at a joint
up to 3

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5
Q

closed chain

A

proximal rotates against fixed distal

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6
Q

open chain

A

distal rotates against fixed proximal

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7
Q

convex-concave relationship improves

A

congruency
surface area for dissipating contact forces
helps glide motion between bones

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8
Q

three movements between joints

A

roll - changes contact surface
slide - same cs
spin - rotations, same cs

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9
Q

convex on concave

A

convex rolls and slides in opposite directions

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10
Q

concave on convex

A

concave rolls and slides in similar directions

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11
Q

where do articular surfaces fit best?

A

near end of ROM
called close packed position
provides stability to joint

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12
Q

loose packed position

A

ligaments slackened
increase in accessory movements
least congruent near midrange

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13
Q

when is the joint least congruent?

A

near the midrange

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14
Q

when is net force zero

A

when acceleration of mass is zero
not moving

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15
Q

what is the force that acts on body called?

A

a load

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16
Q

time of loading

A

how long

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17
Q

rate of loading

A

how fast

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18
Q

viscoelastic

A

tissues in which physical properties associated with stress/strain curve change as function of time
creep phenomenon

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19
Q

creep

A

progressive strain when exposed to constant load over time
reversible

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20
Q

rate-sensitivity of viscoelastic

A

increased stiffness affords greater protection to underlying bone at time when forces acting on joint are greatest

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21
Q

internal forces

A

within body
active or passive

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22
Q

external forces

A

outside body
gravity or external load

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23
Q

isometric

A

internal torque = external torque

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24
Q

2 ways to produce torque

A

1) force perpendicular to AoR
2) moment arm distance > zero

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25
Q

concentric

A

internal > external

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26
Q

eccentric

A

external > internal

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27
Q

mechanics

A

study of motion of objects and the forces that cause motion

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28
Q

rigid-body mechanics

A

assume rigidity
saves considerable mathematical and modeling work without a great loss of accuracy

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29
Q

moment arm

A

perpendicular distance between axis of rotation and line of force

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30
Q

torque/moment

A

force multiplied by moment arm
tends to rotate body
could by internal or external

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31
Q

internal force

A

within body
produced by active muscle

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32
Q

joint reaction force

A

in reaction to net effect of internal and external forces
if IT and ET are equal, JRF = 0

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33
Q

mechanical advantage

A

ratio of internal moment arm to external moment arm
output force to input force

MA = a/b = Fb/Fa

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34
Q

primary movement of human body

A

through rotations of its limbs and trunks
non linear movement

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35
Q

what are movement and posture based on?

A

instantaneous interaction between internal and external torques

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36
Q

lever

A

rigid bar that turns about an axis of rotation or fulcrum
rotates about axis as result of force
force acts against resistance

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37
Q

lever function

A

create MA
magnify force (MA > 1)
increase speed and ROM through which the end of the lever moves (MA < 1)
balance equal forces (MA = 1)

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38
Q

mnemonic for levers

A

FRE 123

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39
Q

class 1 lever

A

fulcrum in middle
MA <, >, or = to 1
designed for speed and ROM when fulcrum closer to force
designed for strength when fulcrum closer to resistance

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40
Q

class 2 lever

A

resistance in middle
MA is > 1
advantage for force - farce arm is longer

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41
Q

class 3 lever

A

effort in middle
MA is < 1
advantage in speed and ROM

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42
Q

statics

A

no acceleration
described as equilibrium

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43
Q

dynamics

A

acceleration is occurring
system is not in equilibrium

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44
Q

where to hold the bat?

A

bottom for more torque
chocked up for speed

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45
Q

what percent of all musculoskeletal complaints is the shoulder responsible for?

A

~16%

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46
Q

orientation of clavicle:

A

deviated about 20 degrees posterior to frontal plane

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47
Q

orientation of scapula:

A

deviated about 35 degrees anterior to frontal plane

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48
Q

retroversion of humeral head:

A

about 30 degrees posterior to medial-lateral axis at elbow

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49
Q

how many joints make up the shoulder complex?

A

4
AC, GH, SC, scapulothoracic (ST)

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50
Q

arthrokinematics: roll

A

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

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51
Q

arthrokinematics: slide

A

single point on one surface contacts multiple points on another

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52
Q

arthrokinematics: spin

A

a single point on one surface contacts a single point on another

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53
Q

roll, spin, slide - convex/concave relationship

A

convex - knuckle and arm, opposite movement
concave - cupped hand and arm, same movement

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54
Q

which part of clavicle is convex/concave?

A

longitudinal is convex
transverse is concave

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55
Q

SC arthrokinematics

A

depression: glide superior, roll inferior
elevation: glide inferior, roll superior
protraction: glide and slide anterior
retraction: glide and slide posterior

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56
Q

SC arthrokinematics - depression

A

depression: glide superior, roll inferior

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57
Q

SC arthrokinematics - elevation

A

elevation: glide inferior, roll superior

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58
Q

SC arthrokinematics - protraction

A

protraction: glide and slide anterior

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59
Q

SC arthrokinematics - retraction

A

retraction: glide and slide posterior

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60
Q

ST joint elevation

A

scapula slides sup on thorax

anterior tilting at AC

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61
Q

ST depression

A

from elevated position, scap slides inf on thorax

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62
Q

ST protraction

A

medial border of scap sides ant-lat on thorax away from midline

internal rotation at AC joint

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63
Q

ST retraction

A

medial border of scap slides post-med on thorax toward midline

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64
Q

ST upward rotation

A

inf angle of scap rotates sup-lat, faceing glenoid fossa upward

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65
Q

ST downward rotation

A

from upward rotated position, inf angle of scap rotates in inf-med direction

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66
Q

what happens at SC and AC during ST elevation

A

ST elevation
SC elevation
AC downward rotation

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67
Q

what happens at SC and AC during ST protraction

A

ST protraction
SC protraction
slight horizontal place adjustments at AC

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68
Q

what happens at SC and AC during ST upward rotation

A

ST upward rotation
SC elevation
AC upward rotation

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69
Q

relationship of elevation at SC and upward rotation at AC

A

most of SC movement occurs 20-90 degrees
AC movement picks up from 140-180 degrees
impingement can occur after 90 degrees

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70
Q

functional importance of upward rotation at ST

A

glenoid need to sit upward
slight upward rotation needed for length tension relationship
subacromial spaces maintained to avoid impingement
accounts for approximately 1/3 of near 180 degrees
of shoulder abd and flex

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71
Q

how much humeral head does glenoid fossa cover

A

only about 1/3
longitudinal head is 1.9 times larger
transverse head is 2.3 times larger

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72
Q

what is a slap tear

A

labral tears at the top of the glenoid

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73
Q

superior glenohumeral ligament

A

anatomic neck, above lesser tubercle

adduction, inferior and AP translations of humeral head

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74
Q

middle GH lig

A

along anterior aspect of anatomic neck; also bends with subscap tendon

anterior translation of humeral head, especially in about 45-60 degrees of abduction; external rotation

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75
Q

inferior GH lig: axillary pouch

A

as a broad sheet to the anterior-inferior and posterior -inferior margins of the anatomic neck

90 degrees of abduction, combined with AP and inferior translation

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76
Q

inferior GH lig: anterior band

A

as a broad sheet to the anterior-inferior and posterior -inferior margins of the anatomic neck

90 degrees of abduction and full external rotation; anterior translation of humeral head

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77
Q

inferior GH lig: posterior band

A

as a broad sheet to the anterior-inferior and posterior -inferior margins of the anatomic neck

90 degrees of abduction and full internal rotation

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78
Q

coracohumeral lig

A

anterior side of greater tubercle; also blends with superior capsule and supraspinatus tendon

adduction; inferior translation of the humeral head; external rotation

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79
Q

GIRD

glenohumeral internal rotation deficit

A

common in overhead athletes
GH and ST deficiency
20 degree or greater loss of internal rotation

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80
Q

high velocity abduction and external rotation during cocking phase

A

motion twists and elongates middle GH ligh and anterior band of inferior GH lig
active motion tends to translate humeral head anteriorly

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81
Q

throwing phases

A

wind-up
early cocking
late cocking
acceleration
deceleration
follow-through

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82
Q

injuries during late cocking

A

anterior GH instability
RTC
SLAP tear
quadrilateral space syndrome
medial elbow instability
capitellar OCD

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83
Q

injuries during acceleration

A

internal impingement
rotator cuff tear (RTC)
scapulothoracic bursitis
medial elbow instability
olecranon apophysitis / stress fx

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84
Q

injuries during decleration

A

RTC
SLAP tear
subacromial impingement
posteromedial elbow impingement

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85
Q

injuries during follow through

A

olecranon apophysitis
olecranon stress fracture

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86
Q

why is the glenoid labrum so vulnerable to injury?

A

only loosely attached to glenoid rim
~50% of fibers of tendon of long head of biceps direct extensions of superior glenoid labrum

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87
Q

glenoid fossa tilt

A

5 degree upward tilt relative to medial border of scapula

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88
Q

GH abduction

A

inferior glide
superior roll

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89
Q

GH adduction

A

superior glide
inferior roll

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90
Q

external rotation
(vertical axis)

A

anterior glide
posterior roll

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91
Q

internal rotation
(vertical axis)

A

posterior glide
anterior roll

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92
Q

flexion

A

anterior spin

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93
Q

extension

A

posterior spin

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94
Q

scapulohumeral rhythm

A

for every 3 degrees of shoulder abduction, 2 degrees by GH abduction and 1 degree by ST upward rotation

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95
Q

6 kinematic principles associated with full abduction of shoulder

A
  1. 2:1 SH rhythm shoulder abd 180 because 120 GH abd and 60 ST upward rotation
  2. 60 UR of scap because SC elevation and AC UR
  3. clavicle retracts at SC during shoulder abd
  4. scap posteriorly tilts and externally rotates during shoulder abd
  5. clavicle posteriorly rotates around own axis during shoulder abd
  6. GH externally rotates during shoulder abd
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96
Q

scapular statistics

A

medial border ~3” from spine
between T2-T7
flat against thorax and rotated 30-35 degrees anterior to frontal plane

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97
Q

SICK scapula

A

scapular malposition
inferior medial border prominence
coracoid pain and malposition
dysKinesis of scapula (lack of proper movement)

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98
Q

3 types of dyskinesis

A
  1. inferior medial scapular prominence
  2. medial scapular border prominence
  3. superomedial border prominence

1 and 2 associated with SLAP
3 associated with impingement and rotator cuff lesions

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99
Q

proximal stabilizers

A

originate on spine, ribs, and cranium
insert on scapula and clavicle

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100
Q

distal mobilizers

A

originate on scapula and clavicle
insert on humerus or forearm

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101
Q

ST elevators

A

upper trap
levator scapulae
rhomboids

support posture of shoulder girdle and upper extremity

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102
Q

ST depressors

A

lower traps
latissimus dorsi
pectoralis minor
subclavius

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103
Q

ST protractor

A

serratus anterior

forward pushing and reaching
final phase of pushup

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104
Q

ST retractors

A

middle trap - best
rhomboids
lower trap

middle trap has optimal line of force to retract scapula
active during pulling
scapular drifts into protraction of trap paralyzed

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105
Q

ST upper rotators

A

serratus anterior
upper and lower trap

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106
Q

ST downward rotators

A

rhomboids
pectoralis minor

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107
Q

muscle produces torque at a joint if

A
  1. produces force in plane perpendicular to AoR (axis of rotation) of interest

AND

  1. acts with associated moment arm distance > zero
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108
Q

three groups of elevators

A
  1. elevate humerus at GH
  2. scapular muscles that control upward rotation of ST
  3. rotator cuff that control dynamic stability at GH
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109
Q

muscles responsible for elevation of arm by group

A

GH muscles
~ anterior and middle deltiod
~ supraspinatus
~ coracobrachialis
~ biceps long head
ST
~ serratus anterior
~ trap (upper and lower)
RC
~ supra
~ infra
~ teres minor
~ subscap

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110
Q

which RC have limited moment arm to abduct GH joint?

A

upper fibers of infraspinatus and subscapularis

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111
Q

supraspinatus role in shoulder abduction

A

rolls humeral head superiorly while also compressing joint

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112
Q

how cuff muscles control abduction at GH

A

supra: main compressor, drives superior roll
infra, TM, sub: exert depression on humeral head
infra and TM: externally rotate humerus

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113
Q

serratus anterior paralysis

A

downward rotated scapula - flaring
winging scapula
shortening of pec minor

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114
Q

subacromial impingement syndrome

A

most common painful disorder of shoulder
supra tendon, biceps long head tendon
“when I raise my arm, it hurts”
abd of 60 - 120 called the painful arc

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115
Q

possible causes of impingement syndrome

A
  1. abnormal kinematics at GH and ST
  2. slouched posture affecting ST alignment
  3. fatigue, weakness, poor contorl, tightness of GH & ST muscles
  4. inflammation and swelling in and around subacromial space
  5. excessive wear and subsequent degeneration of tendons of rotator cuff
  6. instability of GH
  7. adhesions in inferior GH
  8. excessive tightness in posterior GH
  9. osteophytes forming aroung AC
  10. abnormal shape of acromion or coracoaromial arch
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116
Q

where does slap tear affect.

A

posterior band of inferior GH lig

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117
Q

what does GIRD affect

A

posterior band of the inferior GH lig

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118
Q

Is motion of shoulder required for supination and pronation of the palm?

A

no

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119
Q

what joints make up the elbow and forearm complex?

A

humero-ulnar
humero-radial
proximal radio-ulnar
distal radio-ulnar

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120
Q

what provides stability at humero-ulnar joint?

A

tight fit between trochlea and trochlear notch

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121
Q

what type of joint is the elbow?

A

ginglymus or hinged

modifies hinge because there is slight axial rotation as it flexes/extends

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122
Q

what is the normal angle of the elbow

A

15 degrees valgus
ulna deviates laterally relative to humerus
carrying angle

valgus deformity - 30 lateral
varus deformity - 5 medial

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123
Q

who would have greater carrying angle between men and women?

A

women by 2 degrees
greater on dominant arm regardless of gender

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124
Q

valgus when elbow is extended

A

exceeds ~20-25 degrees

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125
Q

gunstock deformity

A

varus deformity where forearm deviated toward midline
can be born with it

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126
Q

what form of trauma can varus/valgus deformity result from?

A

severe fracture through growth plate of distal humerus in children

excessive valgus may damage ulnar nerve as it cross medial to elbow. it will slip in and out of the groove

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127
Q

articular capsule of elbow

A

encloses HU, HR, and PRU
thin and reinforced anteriorly by oblique bands of
fibrous tissue
synovial membrane lines internal surface of capsule

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128
Q

collateral ligaments stregnthen …

A

articular capsule
they provide an important source of stability to elbow joint

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129
Q

medial collateral ligament

A

anterior fibers: strongest and stiffest, commonly torn by throwers, most significant resistance against valgus
posterior fibers
transverse fibers:

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130
Q

anterior fibers of MCL

A

origin: medial epicondyle
insertion: medial coronoid process
taught through sag plane movement (flex/ext)
provide articular stability throughout entire ROM

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131
Q

posterior fibers of MCL

A

origin: posterior medial epicondyle
insertion: medial olecranon process
resist valgus and extreme elbow flexion

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132
Q

transverse fibers of MCL

A

cross from olecranon to coronoid
do not resist anything

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133
Q

dynamic medial stabilizers

A

proximal fibers of wrist flexor and pronator groups
resist excessive valgus at elbow
most important: flexor carpi ulnaris

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134
Q

fall onto an outstretched arm and hand (FOOSH)

A

fully extended elbow forced into excessive valgus
may result in fracture of radius, ulnar nerve, anterior capsule or MCL injury

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135
Q

how much compression force does radius absorb?

A

80%

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136
Q

lateral collateral lig

A

origins on lateral epicondyle and immediately splits into two fiber bundles
taut during full flexion
stabilize during varus

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137
Q

radial collateral lig

A

fans from lateral epicondyle to blend with annular lig

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138
Q

lateral (ulnar) collateral lig

A

spans from lateral epicondyle and inserts to superior crest of ulna

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139
Q

guy wires of elbow

A

LUCL and AMCL
provide medial-lateral stability to ulnar during sag plane movement

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140
Q

what does rupture of LCL cause?

A

varus of elbow and posterior lateral rotary instability

expressed as excessive external rotation of forearm

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141
Q

motions that increase tension in CL of elbow

A

AMCL - valgus, ext/flex
PMCL - valgus, flex
LRCL- varus, external rotation
LUCL - varus, external rotation, flex
annular- distraction of radius, external rotation

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142
Q

elbow flexion contracture

A

muscles abnormally stiff after long periods of
immobilization in flexed and shortened position
increased stiffness may occur in anterior capsule and
some anterior fibers of MCL
tightness in flexors if cannot fully extend

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143
Q

in what activities does elbow extension occur?

A

throwing
pushing
reaching

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144
Q

maximal range of passive ROM generally available to elbow

A

5 degrees beyond neutral extension through 145 degrees of flexion

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145
Q

functional arc of elbow

A

30 - 130 degrees of flexion
loss of extremes usually results in only minimal functional impairment

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146
Q

humero-ulnar joint articulation

A

concave trochlear notch of ulna
convex trochlea of humerus

motion limited to sagittal plane

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147
Q

how much of articular surface does hyaline cover of trochlea and trohlear notch?

A

trochlea - 300 degrees
notch - 180 degrees

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148
Q

what stabilizes healthy HU joint in extension?

A

articular congruency and increased tension in stretched connective tissues

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149
Q

humero ulnar joint flexion

A

roll and slide superior

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150
Q

HUJ dislocation

A

trochlear notch of ulna may dislocate posterior to trochlea of humerus in severe elbow injuries

caused by FOOSH

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151
Q

HRJ articulation

A

between cuplike fovea of radial head and reciprocally shaped rounded capitulum

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152
Q

HRJ flexion

A

roll and slide superiorly

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153
Q

explain the motion of supination and pronation

A

occurs around an axis of rotation that extends from radial head through ulnar head - an axis that intersects and connects both radio-ulnar joints

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154
Q

when are radius and ulnar parallel?

A

in full supination

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155
Q

when does radius cross over ulna?

A

in full pronation
thumb will stay with radius in pronation

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156
Q

what is the midway between complete pronation and supination?

A

thumbs up position

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157
Q

what are the average ROM’s through pro/sup

A

pronation: 75 degrees
supination: 85 degrees

several ADLs require only 100 degrees rotation, 50 pro through 50 sup

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158
Q

how many degrees of rotation can a person lack and still complete ADLs?

A

30 degrees

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159
Q

how to compensate for pro/sup?

A

pronation: internally rotating shoulder
supination: externally rotating shoulder

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160
Q

supination at PRUJ

A

rotation of radial head with fibro-osseous ring formed by annular ligament and radial notch of ulnar

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161
Q

which arm bone is fixed in open chain sup/pro?

A

ulna

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162
Q

DRUJ supination (open chain)

A

roll and slide inferior

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163
Q

PRUJ supination (open chain)

A

external rotation

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164
Q

DRUJ pronation (open chain)

A

roll and slide superior

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165
Q

PRUJ pronation (open chain)

A

internal rotation

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166
Q

screw home of elbow

A

proximal migration of radius and increased joint compression of HRJ

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167
Q

PRUJ pronation (closed chain)

A

external rotation

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168
Q

DRUJ pronation (closed chain)

A

slide posterior, roll anterior

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169
Q

PRUJ supination (closed chain)

A

internal rotation

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170
Q

DRUJ supination (closed chain)

A

slide anterior, roll posterior

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171
Q

force-couple

A

used to pronate forearm from weight bearing position

infraspinatus rotates humerus relative to fixed scapula, whereas pronator quadratus rotates ulna relative to fixed radius

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172
Q

arthrokinematics of pro/sup at PRUJ while weight bearing

A

annular lig and radial notch of ulna rotate around fixed radial head

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173
Q

arthrokinematics of pro/sup at PRUJ while non-weight bearing

A

radial head rotates within ring formed by annular lig and radial notch of ulna

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174
Q

arthrokinematics of pro/sup at DRUJ while weight bearing

A

convex ulnar head rolls and slides in opposite direction on concave ulnar notch of radius

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175
Q

arthrokinematics of pro/sup at DRUJ while non-weight bearing

A

concavity of ulnar notch of radius rolls and slides in similar directions on convex ulna head

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176
Q

function of elbow muscles

A

muscles that attach distally on ulna flex/extend but do not pro/sup

muscles that attach distally on radius my flex/extend but also can pro/sup

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177
Q

primary elbow flexors

A

biceps brachii
brachialis
brachioradialis
pronator teres

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178
Q

brachialis has larger …
(biomech variables)

A

volume: 59.3 cm3
physiologic cross-sectional area: 7.0 cm2

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179
Q

brachioradialis has larger …
(biomech variables)

A

internal moment arm: 5.19 cm

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180
Q

biceps brachii O/I

A

origin on scapula
insertion on radial tuberosity on radius

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181
Q

biceps brachii EMG signal

A

maximal when both flexion and supination simultaneous

low signal when flexion with pronation

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182
Q

brachialis O/I

A

origin: anterior humerus
insertion: proximal ulna

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183
Q

brachialis sole purpose

A

to flex elbow
expected to generate greatest force of any muscle crossing elbow

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184
Q

brachioradialis O/I

A

origin: lateral supracondylar ridge of humerus
insertion: styloid process of radius

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185
Q

what is the longest of all elbow muscles?

A

brachioradialis

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186
Q

what does maximal shortening of brachioradialis cause?

A

full elbow flexion and rotation of forearm to near neutral position

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187
Q

bowstring

A

brachioradialis muscle on anterior-lateral aspect of forearm

resisted elbow flexion, from a position of about 90 degrees of flexion and neutral forearm rotation

188
Q

triceps brachii O/I

A

long head origin: infraglenoid tubercle
medial head origin: posterior side of humerus
lateral head origin: along radial groove
insertion: olecranon process

189
Q

action of long head to triceps

A

extend and adduct shoulder

190
Q

triceps long head biomech variables

A

volume: 66.6 cm3

191
Q

anconeus location

A

between lateral epicondyle of humerus and along posterior aspect of proximal ulna

small cross-sectional area and small moment arm for extension

provides longitudinal and ML stability across HUJ

192
Q

combining shoulder rotation with supination and pronation allow the hand to rotate how many degrees?

A

nearly 360 degrees

193
Q

supinator muscles

A

supinator
biceps brachii

radial wrist extensors
extensor pollicis longus
extensor indicis
brachioradialis (from pronated position)

194
Q

pronator muscles

A

pronator teres
pronator quadratus

flexor carpi radialis
palmaris longus
brachioradialis (from supinated position)

195
Q

how many degrees of ulnar tilt and what motion does it restrict?

A

25 degrees of ulnar tilt

restricts radial deviation
scaphoid runs into radial styloid

196
Q

how many degrees of palmar tilt and what motion does it restrict?

A

10 degrees of palmar tilt

resits extension

197
Q

what is the shape of the distal articular surface of the radius?

A

concave

198
Q

two commonly injured ligaments in distal radio-ulnar joint?

A

ulnar collateral
palmar capsular

199
Q

what happens when fracture heals abnormally?

A

might lose ROM due to misalignment in joint

200
Q

who develops ulnar drift?

A

those who have degenerative arthritis

201
Q

the palmar side of carpal bones are what shape and what ligament arches over?

A

concave
transverse carpal ligament

202
Q

four points that transverse carpal ligament connects to

A

pisiform and hamate on ulnar side
tubercles of scaphoid and trapezium on radial side

203
Q

carpal tunnel is a passage way for what?

A

median nerve and tendons of extrinsic flexor muscles of digits

restrains tendons from bowstringing when wrist flexes

204
Q

which carpals are vulnerable to compression injuries?

A

scaphiod and lunate

205
Q

what is AVN

A

bone death from lack of blood flow

206
Q

scaphoid is what percent of all carpal fractures?

A

60-70%

207
Q

common MOI for carpal fractures?

A

fully supinated forearm
wrist fully extended and radially deviated

second common is punching

208
Q

what artery supplies scahpoid?

A

radial artery
anterior interosseous artery

209
Q

proximal 1/3 of scaphoid relies on what for blood flow?

A

retrograde blood flow because it has poor circulation

210
Q

when scaphoid fracture is present where would be tender?

A

anatomical snuff box

211
Q

location most of scaphoid fractures

A

along “waist” (between poles)

212
Q

management of proximal pole fracture

A

typically require surgery
immobilization for 12+ weeks

213
Q

management of distal pole fracture

A

no surgery if non-displaced
5-6 weeks of immobilization

214
Q

flow of management of suspected scaphoid fracture

A

fracture visible
~displaced - ORIF
~undisplaced - CT
~~ displaced - ORIF
~~ undisplaced - cast or ORIF

no fracture seen
~ MRI
~~ normal - no fracture
~~ abnormal - cast or ORIF
~ splint and review x ray
~~ no fracture with pain - bone scan/MRI
~~ no fracture, no pain - no fracture

215
Q

other injuries associated with scaphoid fracture

A

fracture/dislocation of lunate
fracture of trapezium
fracture of distal radius

216
Q

Keinbock’s (lunatomalacia)

A

unknown cause
AVN of lunate
history of frequent trauma
ex. jack hammer operators

lunate becomes fragmented and shortened

217
Q

treatment of keinbock’s

A

may need to be removed if it totally collapses and disrupts kinematics and kinetics of wrist

mild - immobilization
may need to alter length of ulna or radius to reduce contact
advanced - partial fusion, lunate excision, proximal row carpectomy

218
Q

what three things does treatment of keinbock’s depend on?

A

functional limitation
pain
progression of disease

219
Q

proximal components of radiocarpal joint

A

concave surfaces of radius and adjacent articular disk (triangular fibrocartilage)

220
Q

distal components of radiocarpal joint

A

convex proximal surfaces of scaphoid and lunate

triquetrum when in full ulnar deviation because it contacts articulate disc

221
Q

percent of total compression force through articular disc and how much through scaphoid and lunate?

A

20% through articular disc
80% through scaphoid and lunate

222
Q

when are contact areas greatest in RCJ

A

wrist partially extended and ulnar deviated

this is where maximal grip strength os obtained

223
Q

what is the medial compartment formed by

A

convex head of capitate and apex of hamate fitting into concave recess of scaphoid, lunate and triquetrum

224
Q

lateral compartment

A

concave trapezoid and trapezium fitting into convex scaphoid

has less movement

225
Q

how many degrees of freedom at wrist

A

2

flex/ext
deviation

226
Q

axis for flexion/extension at wrist

A

ML

227
Q

axis for radial and ulnar deviation

A

AP

228
Q

which carpal bone is axis of rotation for hand?

A

capitate

229
Q

wrist flex/ext ROM

A

sagittal plane
total 130-160 degrees
flexes from 0 to 70-85
extends from 0 to 60-75

more flexion due to palmar tilt

230
Q

wrist ulnar/radial deviation ROM

A

frontal plane
total 50-60 degrees
ulnar form 0 to 35-40
radial from 0 to 15-20

231
Q

how to measure wrist devation

A

measured as angle between radius and shaft of 3rd metacarpal

232
Q

average resting position for wrist

A

about 10-15 degrees extension and 10 degrees ulnar deviation

233
Q

what kind of system is wrist

A

double joint system

234
Q

arthro for wrist extension for both midcarpal and radiocarpal joints

A

roll posterior and slide anterior

roll follows fingers
convex on concave

235
Q

arthro for wrist flexion for both midcarpal and radiocarpal joints

A

roll anterior and slide posterior

236
Q

close packed position in wrist

A

full extension

237
Q

arthro for ulnar deviation for both midcarpal and radiocarpal joints

A

roll ulnarly and slide radially
roll follows thumb
convex on concave

238
Q

arthro for radial deviation for both midcarpal and radiocarpal joints

A

roll radially and slide ulnarly

239
Q

which carpal joint has more radial deviation

A

greater at mid-carpal

radiocarpal radial deviation limited because carpus impinges against radial styloid

240
Q

is carpal instability static or dynamic?

A

can be both or either one

241
Q

rotational collapse of wrist

A

zigzag deformity

dorsal intercalated segment instability - lunate’s distal end dorsal
volar intercalated segment instability - lunates distal end volar

242
Q

what happens to produce zigzag deformity

A

compression from both ends

ex: punch or fall

243
Q

what condition weakens ligaments of wrist

A

rheumatoid arthritis

244
Q

double V system of ligaments

A

distal inverted V - medial and lateral legs of palmar intercarpal

proximal inverted V - palmar ulnocarpal and palmar radiocarpal

245
Q

for ulnar deviation, which double V ligs are taut

A

lateral leg
palmar ulnocarpal lig

246
Q

for radial deviation, which double V ligs are taut

A

medial leg
palmar radiocarpal lig

247
Q

wrist extensors

A

extensor carpi radialis longus
extensor carpi radialis brevis
extensor carpi ulnaris

extensor digitorum
extensor indicis
extensor digiti minimi
extensor pollicis longus

248
Q

where is maximal grip

A

30 degrees of extension

249
Q

wirst flexors

A

flexor carpi radialis
flexor carpi ulnaris
palmaris longus

flexor digitorum profundus
flexor digitorum superficialis
flexor pollicis longus
abductor pollicis longus
extensor pollicis brevis

250
Q

radial wrist deviators

A

extensor carpi radialis longus
extensor carpi radialis brevis
extensor pollicis longus
extensor pollicis brevis
flexor carpi radialis
abductor pollicis longus
flexor pollicis longus

251
Q

wrist ulnar deviators

A

extensor carpi ulnaris
flexor carpi ulnaris
flexor digitorum profundus and superficialis
extensor digitorum

252
Q

shape of proximal base of 1st metacarpal

A

convex longitudinal
concave transverse

253
Q

thumb movements and planes

A

abd/add in sagittal
flex/ext in frontal

254
Q

arthro of thumb abduction

A

roll anteriorly and slide posteriorly

255
Q

arthro of thumb adduction

A

roll posteriorly and slide anteriorly

256
Q

arthro of thumb flexion

A

roll and slide anterior

257
Q

arthro of thumb extension

A

roll and slide posterior

258
Q

MCP movements and planes

A

flex/ext in sag
abd/add in frontal

259
Q

arthro of MCP flexion

A

roll and slide anteriorly

260
Q

arthro of MCP extension

A

roll and slide posteriory

261
Q

arthro of MCP abd

A

roll and slide radially

262
Q

arthro of MCP add

A

roll and slide ulnarly

263
Q

arthro of IP flexion

A

roll and slide anteriorly

264
Q

arthro of IP extension

A

roll and slide posteriorly

265
Q

axial skeleton

A

head, spine, sacrum

266
Q

appendicular skeleton

A

limbs including scapulas

267
Q

how many functional components of the intervertebral junction?

A

3

transverse and spinous processes
apophyseal joints
an interbody joint

268
Q

where does the cauda equina start?

A

L2

269
Q

what plane is spine flex/ext?

A

sag

ML axis

270
Q

what plane is spine lateral flexion?

A

frontal

AP axis

271
Q

what plane is spine axial rotation?

A

horizontal

vertical axis

272
Q

which facets favor which motion?

A

horizontal facets favor axial rotation
vertical facets favor block axial rotation

273
Q

how are collagen fibers arranged?

A

multiple concentric layers
every other layer running in identical directions
orientation of each fiber about 65 degrees from vertical

274
Q

ligamentum flavum

A

between anterior surface of one lamina and posterior surface of lamina below

limits flexion

80% elastin and 20% collagen
acts as barrier to material that could buckle cord in some regions of ROM

275
Q

supraspinous and interspinous ligaments

A

between adjacent spinous processes from C7 to sacrum

limit flexion

interspinous guides sliding motion of facet joints

276
Q

intertransverse ligaments

A

between adjacent transverse processes

limits contralateral lateral flexion and forward flexion

277
Q

anterior longitudinal ligament

A

between basilar part of occipital bone and entire length of anterior surfaces of all vertebral bodies, including sacrum

limits extension or excessive lordosis in cervical and lumbar.
reinforces anterior sides of IVDs

278
Q

posterior longitudinal ligament

A

throughout length of posterior surfaces of all vertebral bodies between axis and sacrum

limits flexion
reinforces posterior sides of IVD

279
Q

capsules of the apophyseal joints

A

margin of each apophyseal joint

strengthen apop joints
surrounds the joint itself

280
Q

when are only muscle contributions considered in mechanics to support spine?

A

lumbar spine neither flexed nor extended
(neutral lordosis)

281
Q

who should not be prescribed flexion exercises?

A

shear pathology - spondylolisthesis

282
Q

ROM at atlanto-occipital joint C0-C1

A

flex - 5
ext - 10
total - 15

axial rot - none
lateral flexion - 5

283
Q

ROM at atlanto-axial joint complex C1-C2

A

flex - 5
ext - 10
total - 15

axial rot - 35-40
lateral flexion - none

284
Q

ROM at intracervical region C2-C7

A

flex - 35-40
ext - 55-60
total - 90-100

axial rot - 30-35
lateral flexion - 30-35

285
Q

total ROM across craniocervical region

A

flex - 45-50
ext - 75-80
total - 120-130

axial rot - 65-75
lateral flexion - 35-40

286
Q

arthro of cervical extension

A

AO - roll posterior, slide anterior
AA - tilt posterior
ICR - slide posterior, ALL tense

287
Q

arthro of cervical flexion

A

AO - roll anterior, slide posterior
AA - tilt anterior
ICR - slide anterior, lig nuchae, interspinous tense

288
Q

arthro of protraction of cranium

A

lower to mid cervical flexes and upper craniocervical extends

289
Q

arthro of retraction of cranium

A

lower to mid cervical extends and upper craniocervical flexes

290
Q

arthro of craniocervical axial rotation

A

slides in opposite directions

spinous process to left - left transverse slides anterior and right slides posterior

291
Q

arthro of craniocervical lateral flexion

A

AOJ - roll toward flexion and slide away
ICR - opposite slides.

292
Q

spinal coupling between lateral flexion and axial rotation

A

45 degree inclination of articular facets of C2-C7

ex lateral flexion to right occurs with slight axial rotation to the right

293
Q

compensatory action in spinal coupling

A

during lateral flexion to the right, cranium rotates to left to conceal that it actually rotated to the right

helps eyes fixate of stationary object

294
Q

ROM for thoracic region

A

flex: 30-40
ext: 20-25
total: 50-65

axial rotation: 30-35
lateral flexion: 25-30

295
Q

arthro of thoracolumbar flexion

A

superior slide in both thoracic and lumbar

296
Q

arthro of thoracolumbar extension

A

inferior slide in both thoracic and lumbar

297
Q

thoracolumber flexion arc

A

85

35T + 50L

298
Q

thoracolumber extension arc

A

35-40

20-25T + 15L

299
Q

arthro of thoracolumbar lateral flexion

A

slides in opposite directions.
inferior sliding on the side you are bending towards

300
Q

thoracolumbar lateral flexion arc

A

45

25T + 20L

301
Q

lumbar ROM

A

flex: 40-50
ext: 15-20
total: 55-70

axial rotation: 5-7
lateral flexion: 20

302
Q

anatomic consideration of the sacroiliac joints

A

pelvic ring transfers body weight bidirectionally between trunk and femurs
strength of ring depends on tight fit of sacrum wedged between two halves of pelvis

303
Q

nutation at pelvis

A

sacrum tilts anteriorly
iliac tilts posteriorly

hip flexors and lumbar extensors are tight

304
Q

counternutation at pelvis

A

sacrum tilts posteriorly
iliac tilts anteriorly

hip extensors and abdominal muscles are tight

305
Q

how thick is the end plate of a vertebra

A

about 0.6 mm thick
it is thinnest in the central region

306
Q

describe trabecular design

A

three orientations - one vertical and two oblique

307
Q

how does a schmorl’s node form?

A

local area of bone collapses under end plate to create a pit or crater

neutral spinal compression
often misdiagnosed as a herniated or degenerated disc

308
Q

3 major components of IVD

A

nucleus pulposus
annulus fibrosis
end plates

309
Q

load bearing abilities of annulus fibrosis

A

able to resist loads when disc is twisted

only 1/2 of the fibers can support this while the other half become disabled

under spine compression the annulus fibers bulge outward and become tensed

310
Q

progressive disc injury

A

when little hydrostatic pressure is present
outer annulus bulges outward and inner bulges inward during disc compression

311
Q

define disc bulge

A

expansion of disc material beyond its normal border

312
Q

protrusion

A

disc material is displaced. a TRUE herniation

313
Q

extrusion

A

NP protruded through all layers of AF but remains attached to disc of origin

314
Q

sequestration

A

a free disc fragment located in epidural space.
can migrate

315
Q

what motion is damage to annulus of disc associated with

A

repetitive flexion of the spine through full ROM

316
Q

rotatores

A

attach between transverse and spinous processes of thoracic vertebrae

stabilize, extend and rotate the spine

317
Q

intertransversarii

A

attach between transverse processes of adjacent lumbar vertebrae

lateral flexion and stabilize spine

318
Q

extensors of thoracolumbar spine

A

longissimus
iliocostalis
multifidus groups

319
Q

transversus abdominis

A

deepest muscle layer
maintain internal pressure

320
Q

rectus abdominis

A

between ribs and pubis at front of pelvis
6 pack muscle

321
Q

external oblique

A

twist trunk to opposite side

322
Q

internal oblique

A

twist trunk to same side

323
Q

caution to training psoas

A

substantial spine compression imposed on spine when psoas activated

324
Q

where do the left and right innominate bones connect to form the pelvis?

A

anteriorly at pubic symphysis
posteriorly at sacrum

325
Q

what spinal level is ASIS at?

A

L4

326
Q

3 functions of the pelvis

A

attachment for many muscles
transmits weight of upper body to ischial tubs when
sitting and lower extremities when walking.
supports organs involved in bowel, bladder and
reproductive

327
Q

3 external features of the pelvis

A

large fan shaped wing
cup shaped acetabulum
obturator foramen

328
Q

what is the longest and strongest bone in the body?

A

femur

329
Q

where does the femoral head project at its proximal end?

A

medially and slightly anteriorly

330
Q

which way does the neck displace the shaft of femur?

A

laterally

331
Q

which side of femur displays convexity?

A

anterior

332
Q

how is stress dissipated through femur?

A

compression along posterior shaft
tension along anterior shaft

333
Q

what affect does bowing of the femur have?

A

allows it to bear a greater load.

334
Q

angle of inclination

A

in frontal plane
140-150 at birth
125 in adulthood

335
Q

normal, vara and valga angles of inclination

A

normal: 125
vara: 105
valga: 140

336
Q

severe malalignment of femoral head and acetabulum may lead to…

A

dislocation or stress induced degeneration of hip

337
Q

what is femoral torsion?

A

rotation between shaft and neck

normally 15 degrees anterior to ML axis

338
Q

normal and excessive anteversion and retroversion of femoral torsion angles

A

normal: 15
excessive: 35
retroversion: 5

339
Q

what can excessive anteversion that persists into adulthood increase the likelihood of?

A

hip dislocation
articular incongruence
increased joint contact force
increased wear on articular cartilage

may lead to secondary OA

340
Q

what gait pattern is excessive anteversion associated with?

A

in-toeing

exaggerated hip internal rotation
compensatory to guide head back into acetabulum

341
Q

what muscles shorten with excessive anteversion?

A

internal rotator muscles and various ligaments.
this reduces external rotation ROM
common in CP with angle of 25-45

342
Q

how does acetabulum project from pelvis?

A

laterally with varying amounts of inferior and anterior tilt

343
Q

what can a dysplastic acetabulum lead to?

A

chronic dislocation and increased stress

leading to degeneration or OA

344
Q

center edge angle

A

35

smaller angle leads to less superior coverage. lead to superior dislocation and high compression

CEA of 15 reduces normal contact area by 35%

345
Q

acetabular anteversion angle

A

20

larger angle leads to anterior dislocation

346
Q

where is excessive acetabular anteversion exposed?

A

anteriorly

347
Q

what happens when acetabular anteversion is severe?

A

anterior dislocation and lesions of anterior labrum especially at extremes of external rotation

348
Q

when is acetabulum retroverted?

A

if it projects directly laterally or even posterior-laterally

349
Q

in hip flexion with knee extended which tissues are taut?

A

hamstrings

350
Q

in hip flexion with knee flexed which tissues are taut?

A

inferior and posterior capsule
gluteus max

351
Q

in hip extension with knee extended which tissues are taut?

A

iliofemoral lig
some of pubofemoral and ischiofemoral ligs
psoas major

352
Q

in hip extension with knee flexed which tissues are taut?

A

rectus femoris

353
Q

in hip abduction which tissues are taut?

A

pubofemoral lig
adductor muscles

354
Q

in hip adduction which tissues are taut?

A

superior fibers of ischiofemoral lig
iliotibial band
abductors - TFL, glute med

355
Q

in hip internal rotation which tissues are taut?

A

ischiofemoral lig
external rotators - piriformis, glute max

356
Q

in hip external rotation which tissues are taut?

A

iliofemoral lig
pubofemoral lig
internal rotators - TFL, glute min

357
Q

what is the close packed position of the hip

A

full extension, with slight internal rotation and slight abduction

elongates most of capsule

358
Q

most congruent position in hip

A

NOT the same as close packed

90 deg flexion, moderate abduction and external rotation

359
Q

femoral on pelvic

A

vex on cave

femur around fixed pelvis

360
Q

pelvic on femoral

A

cave on vex

pelvis over fixed femur

361
Q

hip movements in their planes

A

flex/ext in sag
abd/add in frontal
rotation in hori

362
Q

kyphosis is related to what motion of pelvis?

A

nutation
sacral ant
ilium post

363
Q

lordosis is related to what motion of pelvis?

A

counternutation
sacral post
ilium ant

364
Q

femoral on pelvis flexion

A

roll post, slide ant
spin

365
Q

femoral on pelvis extension

A

roll ant, slide post
spin

366
Q

femoral on pelvis abduction

A

roll med, slide lat

367
Q

femoral on pelvis adduction

A

roll lat, slide med

368
Q

femoral on pelvis internal rotation

A

roll internal, slide external

369
Q

femoral on pelvis external rotation

A

roll external, slide internal

370
Q

lumbopelvic rhythm

A

rotation of pelvis over femoral heads typically changes configuration of lumbar spine

371
Q

ipsidirectional LPR

A

pelvis and lumabr spine rotate in same direction

bend over

372
Q

contradirectional LPR

A

pelvis rotates in one direction while lumbar spine rotates in opposite direction

stand back up

373
Q

pelvic on femoral flexion

A

roll and slide anterior

pelvis tilt anterior
iliopsoas and erector spinae involved

374
Q

pelvic on femoral extension

A

roll and slide posterior

pelvis tilt posterior
taut iliofemoral lig

375
Q

pelvic on femoral abduction

A

roll and slide inferior

ilium goes inf

376
Q

pelvic on femoral adduction

A

roll and slide superior

ilium goes sup

377
Q

pelvic on femoral internal rotation

A

opposite hip rolls and slides internal

378
Q

pelvic on femoral external rotation

A

opposite hip rolls and slides external

379
Q

hip flexors

A

iliopsoas
sartorius
TFL
rectus femoris
adductor longus
pectineus

adductor brevis
gracilis
glute min (ant fibers)

380
Q

hip adductors

A

pectineus
adductor longus
gracilis
adductor brevis
adductor magnus

biceps femoris (long head)
glute max (lower fibers)
quadratus femoris

381
Q

hip internal rotators

A

no primary

glute min (ant fibers)
glute med (ant fibers)
TFL
adductor longus
adductor brevis
pectineus

382
Q

hip extensors

A

glut max
biceps femoris (long head)
semitendinosus
semimembranosus
adductor magnus (post head)

glute med (post fibers)
adductor magnus (ant head)

383
Q

hip abductors

A

glute med
glute min
TFL

piriformis
sartorius

384
Q

hip external rotators

A

glute max
piriformis
obturator internus
gemellus superior
gemellus inferior
quadratus femoris

glute med (post fibers)
glute min (post fibers)
obturator externus
sartorius
biceps femoris (long head)

385
Q

FonP hip flexion laying down
normal activation of abdo muscles

A

posterior pelvis tilt

rectus femoris
rectus abdominis
psoas
iliacus

386
Q

FonP hip flexion laying down
reduced activation of abdo muscles

A

anterior pelvis tilt
back extended
lordosis

rectus abdominis not pulling as hard

387
Q

biomechanical consequences of coxa vara

A

positive
~ increased moment arm
~ alignment may improve joint stability

negative
~ increased bending moment arm increases bending moment - increases shear force
~decreased functional length of hip abductors

388
Q

biomechanical consequences of coxa valga

A

postive
~decreased bending moment arm - decreased shear forces
~increased functional length of hip abductor muscles

negative
~decrease moment arm
~alignment may favor joint dislocation

389
Q

trendelenburg

A

gluteus med weakness

if right weak, right elevates and left drops

390
Q

compensated trendelenburg

A

trunk moves to weaker side
lean to weaker side
shortens lever arm

391
Q

anterior pelvic tilt

A

ASIS inf and PSIS sup
hip flexion

392
Q

posterior pelvic tilt

A

ASIS sup and PSIS inf
hip extension

393
Q

active and passive insufficiency

A

AI: two joint muscle cannot complete full ROM. if hip is flexed, knee can attain full flexion. if hip is extended, knee cannot fully flex

PI: two joint muscle cannot stretch maximally across both joints. if knee is fully extended, hip flexion is limited

394
Q

what fraction of muscles that cross knee also cross hip or ankle?

A

2/3

395
Q

why does axis of rotation change in knee?

A

due to curve of lateral epicondyle

396
Q

describe articular cartilage of posterior patella

A

smooth

397
Q

normal genu valgum angle

A

170-175

398
Q

excessive genu valgum

A

< 170
knock-knee
more women
need to shift weight lat

399
Q

genu varum

A

> 180
bow-leg
more men
need to shift weight med

400
Q

vertical axis of rotation at hip

A

line connecting femoral head to center of knee joint to ankle and foot

mechanically links horizontal plane movements of major joints of entire limb

401
Q

tibio femoral joint

A

convex femoral condyles and flat smaller tibial condyles

402
Q

where does joint stability in knee come from?

A

muscles, ligaments, capsule, menisci, and body weight

403
Q

describe the menisci

A

crescent-shaped, fibrocartilaginous structures

transfrom surfaces of tibia into shallow seats for larger convex femoral condyles

404
Q

what are the free ends of the menisci called?

A

anterior and posterior horns

405
Q

describe coronary ligament in menisci

A

attaches external edge of each meniscus to tibia and capsule

relatively loose to allow pivoting during movement

406
Q

which menisci is more mobile

A

lateral

407
Q

what does the transverse ligament in menisci do?

A

connects both menisci anteriorly

408
Q

where is blood supply to menisci greatest?

A

peripheral (external) border

from capillaries within synovial membrane and capsule

409
Q

blood supply at internal border of menisci

A

essentially avascular

410
Q

describe the medial meniscus

A

oval shape
external border attaches to deep surface of MCL and adjacent capsule

411
Q

describe the lateral meniscus

A

circular shape
external border attaches only to lateral capsule
tendon of popliteus passes between LCL and external border of lateral meniscus

412
Q

actions of popliteus

A

med rot of tibia
flexion of knee
lat rot of femur

unlocking muscle of the knee

413
Q

primary function of menisci

A

reduce compressive stress across tib/fem joint

414
Q

4 secondary functions of menisci

A

stability in motion
lubrication of articular cartilage
providing proprioception
guide knee’s arthrokinematics

415
Q

how much area does menisci increase of joint contact?

A

triples it and decreases pressure

lateral meniscectomy increases peak contact pressure at knee by 230%

416
Q

50% of ACL injuries associated with:

A

concurrent meniscus tears

417
Q

meniscal tears associated with:

A

forceful axial rotation of femoral condyles over partially flexed and weight-bearing knee

axial torsion within compressed knee can pinch and dislodge meniscus

418
Q

bucket-handle tear

A

dislodged or folded flap of meniscus can mechanically block knee movement

makes a clicking sound

419
Q

which meniscus is injured more often

A

medial injured twice as much

axial rotation and external valgus force

420
Q

what does valgu force do at the knee?

A

subsequent large stress on MCL and posterior-medial capsule

can indirectly injure medial meniscus

421
Q

how many degrees of freedom at knee

A

2
flex/ex in sag
int/ext rot when knee is flexed

422
Q

passive frontal plane movement is:

A

passive
6-7 degrees

423
Q

sagittal movement at knee

A

open chain: cave on vex - same
closed chain: vex on cave - opposite

424
Q

describe ML axis of rotation in knee

A

not fixed but migrates within femoral condyles
curved path - evolute
path of axis influenced by eccentric curvature

425
Q

what does the migrating axis do the the moment arm in knee

A

alters length of moment arm of flexor and extensor muscles

external devices have fixed axis and therefore can rotate in dissimilar arc than knee

426
Q

tibia on femoral extension

A

roll and slide anterior

427
Q

tibia on femoral flexion

A

roll and slide posterior

428
Q

femoral on tibia extension

A

roll anterior and slide posterior

429
Q

femoral on tibia flexion

A

roll posterior and slide anterior

430
Q

tib on fem internal rotation

A

tibia internal, femur stationary

431
Q

tib on fem external rotation

A

tibia external, femur stationary

432
Q

fem on tib internal rotation

A

tibia stationary, femur internal

433
Q

fem on tib external roation

A

tibia stationary, femur external

434
Q

axial rotation in the knee increases with what motion

A

knee flexed to 90 degrees

435
Q

external to internal rotation ratio in knee

A

2:1

436
Q

rotation when knee is fully extended

A

maximally restricted by ligaments, capsule, bony congruity

437
Q

what muscle pulls menisci anteriorly

A

quadriceps

438
Q

screw home rotation of knee

A

locking knee in extension requires about 10 degrees of external rotation

described as conjunct rotation - mechanically linked to flexion/extension kinematics

439
Q

what position increases joint congruency and favors stability

A

final position of extension

440
Q

what happens to femur when knee is in full extension?

A

femur slightly medially rotates on the tibia to lock knee joint in place

popliteus is key to unlock it bey flexion and lateral rotation

441
Q

describe how popliteus rotates tibia and femur

A

rotate femur externally to initiate FonT flexion
rotate tibia internally to initiate TonF flexion

442
Q

which muscles stabilize menisci?

A

popliteus
semimembranosus

443
Q

MCL and posterior-medial capsule function

A

resists valgus/abd
resists knee extension
resists extremes of axial rotation (esp. ex rot)

444
Q

MCL and posterior-medial capsule MOI

A

valgus producing force with foot planted
severe hypertension of knee

445
Q

LCL function

A

resist varus/add
resist knee extension
resist extremes of axial rotation

446
Q

LCL MOI

A

varus producing force with foot planted
sever hypertension of knee

447
Q

ACL function

A

resist extension
~ anterior translation of tibia
~ posterior translation of femur
resists extremes of varus, valgus, axial rotation

448
Q

ACL MOI

A

large varus force with foot planted
large axial rotation to knee with foot planted
any combo of above
sever hypertension of knee

449
Q

PCL function

A

resist flexion
~anterior translation of femur
~ posterior translation of tibia
resists extremes of varus, valgus, axial rotation

450
Q

PCL MOI

A

falling on flexed knee when proximal tibia strikes ground
forceful posterior translation of tibia or ant femur
large axial rotaion or varus/valgus
sever hypertension of knee causing gapping of posterior side of joint

451
Q

how many ACL injuries are non contact or minimal contact?

A

70%

452
Q

sartorius

A

hip flexion, external rotation, abd
knee flexion, int rot

453
Q

gracilis

A

hip flex, add
knee flex, int rot

454
Q

rectus femoris

A

knee ext
hip flex

455
Q

vastus group

A

kne ext

456
Q

popliteus

A

knee flex, int rot

457
Q

semimembranosus

A

hip ext
knee flex, int rot

458
Q

semitendinosus

A

hip ext
kne flex, int rot

459
Q

biceps femoris short head

A

knee flex, ex rot

460
Q

biceps femoris long head

A

hip ext
knee flex, ext rot

461
Q

gastrocnemius

A

knee flex
ankle plantar flexion

462
Q

plantaris

A

knee flexion
ankle plantar flexion

463
Q

what does deeper squat require

A

greater force from quadriceps owing to greater external torque on knee

464
Q

what happens with a larger Q-angle

A

larger lateral muscle pull on patella

465
Q

lateral and medial forces in knee should:

A

counteract so that patella tracks optimally during flexion and extension of knee

466
Q

excessive knee external rotation and valgus:

A

increases q-angle and increases lateral bowstringing force on patella

combo of internal femur rotation and external tibia rotation