lecture 6: the shoulder complex Flashcards

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1
Q

what is the shoulder complex made up of

A

clavicle , scap , humerus

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2
Q

what are the 4 joints that make up the shoulder complex

A

GH joint
SC joint
AC joint
ST joint

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3
Q

how much motion of the shoulder complex is at the GH joint and ST joint

A

2/3 at GH
1/3 at ST

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4
Q

what is the normal ROM of the shoulder

A

180°

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5
Q

_____ stabilization is an active force that provides greater control than passive

A

dynamic

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6
Q

what occurs ipsilaterally with shoulder elevation

A

upper thoracic rotation

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7
Q

what is the only structural attachement between axial skeleton and the shoulder

A

sternoclavicular joint

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8
Q

what are the 3 degrees of freedom at the SC joint

A

elevation/depressoin
protraction /retraction
anterior/ posterior rotation

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9
Q

elevation/ depression (of the SC) happen between the ___ and ___

A

disc and clavicle

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10
Q

protraction/ retraction(of the SC) happen between the ___ and ___

A

disc and manubrium

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11
Q

anterior/posterior rotation (of the SC) happen between the ___ and ___

A

clavicle and 1st rub costocartilage

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12
Q

the articulation of the SC joint is what

A

2 plane synovial joint

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13
Q

the disc of the SC joint increases ___ and absorbs ___

A

congruence
forces

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14
Q

The SC joint creates 2 seperate cavities and acts as a ___ point during motion

A

pivot

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15
Q

during elevation / depression (at the SC joint) the clavicle ___ and ___ on the disc

A

rolls and glides

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16
Q

during protraction/retraction (of the SC joint) the sc ___ and ___ roll and slide on the ___

A

disc and clavicle
manubrium

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17
Q

which ligaments of the SC ligaments both limit A/P translation : posterior is primary

A

anterior and posterior SC ligament

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18
Q

the costoclavicular ligament limit ___ of the ___ clavicle

A

elevation
lateral

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19
Q

the anterior costoclavicular lig fibers run ___ and the posterior fibers run ____

A

laterally
medially

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20
Q

which ligament of the SC ligaments resist excessive depression of clavicle : and superior gliding of the clavicle on manubrium

A

interclavicular ligament

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21
Q

during elevation of the SC joint the ___ end of the clavicle moves upward

A

lateral
upward

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22
Q

during SC elevation the medial end rolls ___ and slides ____ on the sternun

A

medial
superiorly
inferiorly

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23
Q

during SC protraction the lateral clavicle moves ___ in the ___ plane

A

lateral
anteriorly
transverse

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24
Q

during protraction of the SC joint the medial clavicel does what on the sternum

A

rolls and slides anteriorly

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25
Q

during depression of the SC joint the lateral end of the clavicle moves___

A

downwards

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26
Q

during depression of the SC joint the medial end of the clavicle does what

A

rolls inferiorly and slides superiorly

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27
Q

during retraction of the SC joint the lateral clavicle moves ___

A

posteriorly

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28
Q

during retraction of the SC joint the medial clavicle does what

A

rolls and slides posteriorly

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29
Q

what joint structure attaches the scapula to lateral clavicle

A

acromioclavicular joint

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30
Q

the AC joint is a ____ synovial joint with ___- DOF

A

plane
3

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31
Q

the AC joint allows the scapula to rotate during arm movement which ___ UE motion

A

increases

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32
Q

is the AC capsule strong or weak

A

weak

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33
Q

is the superior or inferior AC ligament stronger

A

superior

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34
Q

which ligament of the AC joint firmly unites clavicle and scapula

A

coracoclavicular lig

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35
Q

what 2 other ligaments make up the coracoclavicular lig of the AC joint

A

conoid and trapezoid lig

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36
Q

what does the conoid lig resist

A

inferior forces

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37
Q

what does the trapezoid lig resist

A

posterior translation

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38
Q

there is a coupled ____ clavicle rotation and scapula ____ rotation during arm elevation

A

posterior
upward

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39
Q

internal and external rotation(20-35°) of the AC joint occurs around the ___ axis

A

vertical

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40
Q

anterior and posterior tilting (20-40°) of the AC joint occurs around the ___ axis

A

oblique coronal

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41
Q

upward (30°) and downward (17°) rotation of the AC joint occurs around the ___ axis

A

oblique AP

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42
Q

is the AC joint stable ?

A

not rea;;t

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43
Q

is the AC joint susceptible to trauma and degenerative changes

A

yes

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44
Q

what is the most common trauma for the AC joint

A

contact sport or falls on shoulder with arm adducted

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45
Q

what joint is formed by anterior surface of scapula with throax

A

scapulothoracic joint

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46
Q

T/F: the ST joint is a true joint

A

false

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47
Q

the scapula rest from midline between ribs ___-___

A

2-7

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48
Q

what is the resting position of the scapula

A

internally rotated
tilted anteriorly
upwardly rotated

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49
Q

how many degrees of ST joint is required to upwardly rotate during arm elevation

A

60

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50
Q

if you have excessive internal rotation of the ST joint what is that called

A

scapular winging

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51
Q

what happens at the scapula during shoulder flexion/abduction

A

protraction
elevation
upward rotation

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52
Q

what happens at the SC joint during shoulder flexion / abduction

A

protraction (clavicle rolls anterior , slides anterior on manubrium )
posterior rotation w/ elevation (inferior slide , superior roll at the disc)

53
Q

what happens at the AC joint during shoulder flexion / abduction

A

upward rotation (scap/ acromion in relation to clavicle)

54
Q

what happens at the scapular during shoulder lowering / adduction

A

retraction
depression
downward rotation

55
Q

during shoulder lowering / adduction , the SC joint does retraction , depression and anterior rotation … what happens at the SC joint during retraction

A

clavicle rolls posterior , glides posterior on manubrium

56
Q

during shoulder lowering / adduction , the SC joint does retraction , depression and anterior rotation … what happens at the SC joint during anterior rotation (to neutral) w/ depression

A

superior slide and inferior roll at the disc

57
Q

what happens at the AC joint during shoulder lowering/ adduction

A

downward rotation (scapula/ acromion in relation with clavicle)

58
Q

what provides stability for the ST joint

A

structures of the AC and SC joint

59
Q

ST joint is a premier example of a ____ stabilizer

A

dynamic

60
Q

what kind of joint is the glenohumeral joint

A

ball and socket synovial joint

61
Q

how many DOF does the GH joint have

A

3 rotary and 3 translatory

62
Q

is the humeral head or glenoid fossa bigger

A

humeral head

63
Q

which motions of the scapula will influence the GH

A

any motion

64
Q

the proximal surface of the GH is shallow ___

A

concavity

65
Q

the proximal surface of the GH can be ____ or ____

A

retroverted or anteverted

66
Q

the proximal surface of the GH is the ___ ___ of scpaula

A

glenoid fossa

67
Q

the distal surface of the GH joint is what

A

the humeral head

68
Q

what is the angle of inclincation of the distal surface of the GH

A

130-150°

69
Q

what is the angle of torsion of the distal surface of the GH joint

A

30°

70
Q

what does the glenoid labrum enhance

A

fossa concavity

71
Q

the glenoid labrum serves as an attachment site for GH ____ and tendon of what muscle

A

ligaments
long head of biceps

72
Q

what functions to resist humeral head translation , protect bondy edges of fossa, minimize GH joint friction and dissipate joint contact forces

A

glenoid labrum

73
Q

the capsule of the GH tightens with ____ and ____

A

abduction and lateral rotation

74
Q

how much distraction is available at the GH capsules during loose packed position

A

> 2.5 cm

75
Q

the Gh capsule is vulnerable to ____ dislocations

A

anterior

76
Q

the superior GH lig resits ___ and ___ translations of humeral head at 0° of abduction

A

ant and inferior

77
Q

which GH ligaments prevents any translation of humeral head from 0-60° of abduction

A

middle Gh lig

78
Q

the inferior GH ligaments complex is made of of how many components

A

3 (anterior , posterior and axillary pouch)

79
Q

what does the anterior component of the inferior Gh lig complex prevent

A

prevents ant/inf translation (abd/ER)

80
Q

what does the posterior component of the inferior Gh lig complex prevent

A

prevents post/inf translation (abd / IR)

81
Q

what does the axillary pouch component of the inferior Gh lig complex prevent

A

prevents inf translation (abd)

82
Q

what forms the tunnel for the long head of the biceps to pass thru

A

coracohumeral lig

83
Q

how many bands does the coracohumeral lig have

A

2

84
Q

which band of the coracohumeral ligeamnt is at the base of the coracoid to edge of supraspinatus tendon and greater tubercle

A

first band

85
Q

which band of the coracohumeral ligeamnt is at the base of the coracoid into subscapularis and less tubercle

A

second band

86
Q

what forms the vault over the humeral head

A

coracoid , acromion , and coracoacromnial lig

87
Q

what contains subacromial bursa, rotator cuff tendons , and tednon of long head of biceps

A

subacromial space

88
Q

the coracoacromial arch protects subacromial structures and prevents ___ dislocation of the ___

A

superior
humerus

89
Q

the coracoacrominal arch can be an area of impingement with ___ and a narrowed joint space

A

supraspinatus

90
Q

how many degrees of flexion and extension does the GH joint have and around what axis

A

flexion - 120
extension -50
coronal axis

91
Q

medial and laterla rotation of the GH joint is around what axis

A

long

92
Q

abduction of the Gh joint is limited when in neutral or medial rotation by what

A

greater tub

93
Q

how mnay degreees of abduction and adduction is at the GH joint and around what axis

A

90-120
AP axis

94
Q

during elevation of the GH the humeral head slides ___ and rolls ___

A

inferiorly
superior

95
Q

a tight GH capsule can causes the shirting of the humeral head during motion or limit motion AKA ___

A

inferior slide

96
Q

where does gravity pull the arm

A

inferiorly

97
Q

if the arm is loaded what contracts

A

supraspinatus

98
Q

when the arm is loaded there is an ____ inferior subluxation with ___- rotator cuff function

A

increase
decrease

99
Q

during dynamic stabilization of the GH joint what muscle is the prime movers for abduction and flexion

A

deltoids

100
Q

force vectors of the middle delt are larger ____ rather then ____

A

parallel
perpendicular

101
Q

what muscle does the deltoid need synergisitc help from to produce desired rotation of humeral head

A

rotator cuff

102
Q

the .I.T.S perpendicular force component causes some ___ of the humerus but also compresses head into _____ fossa

A

rotation
glenoid

103
Q

the parallel force component (Fx) of the I.T.S muscles offsets superior translatory force from deltoid by pulling the humeral head ____

A

inferiorly

104
Q

what muscles help with lateral rotation to clear the greater tubercle for the GH joint

A

infraspinatus and teres minor

105
Q

which muscle has a large rotary component with large moment arm for adbuction of the GH joint

A

supraspinatus

106
Q

what ligament runs from the greater and lesser tubercles

A

transverse humeral ligament

107
Q

the long head of the biceps can contribute to both ____ and ____ of the shoudler

A

flexion and abduction

108
Q

what muscles helos reinforce the GH joint , centering the head and reducing vertical and anterior shear

A

LHoB

109
Q

the LHoB may also tighten what

A

the labrum

110
Q

overal the dynamic stabilization at any point of ROM of the GH joint is infulenced by
1. force generated by ___ ____
2. force of ____
3. force created by ______ _____
4.articular surface geometry
5. _____ capsuloligamentous forces
6. joint ____ forces

A

primary movers
gravity
muscular stabilizer
passive
reaction

111
Q

all forces of the GH compress the humeral head into the ___ ____

A

glenoid fossa

112
Q

greatest shear forces of the GH joint occur between how many degrees

A

30-60° of elevation

113
Q

which rotator cuff tendon is most vulnerable

A

supraspinatus

114
Q

what kind of tears of common in people over 60

A

RCT

115
Q

if someone has a rotator cuff tear then they will have pain between what degrees

A

60-120° (painful arch)

116
Q

what motion of the shoulder distributes motion between 4 joints , permitting more ROM with more stability

A

scapulohumeral motion

117
Q

the scapulohumeral motion maintains _____ ____ in optimal position for humeral head for better joint ____ and decreased ___

A

glenoid fossa
congruency
shear

118
Q

the scapulohumeral motion maintains good length tension of humeral muscles preventing ____ insufficiency as the scapula rotates up

A

active

119
Q

the scaplohumeral rhythm has first ___ of aduction or___ of flexion

A

30°
60°

120
Q

in the initial phase of scapulohumeral rhythm does the Gh or ST move more

A

GH mostly

121
Q

during the motion of ST moving 60° what happens at the SC and AC joint

A

clavicualr elevation at SC
posterior clavicular rotation at AC

122
Q

the motion during ST motion of 60° causes clavicular elevation at the SC , which muscles upwardly rotate the scapula

A

trapz and SA

123
Q

the motion during ST motion of 60° causes clavicular elevation at the SC , which ligament becomes taut

A

costoclavicular

124
Q

the motion during ST motion of 60° causes posterior clavicular rotation at AC ,, what happens at the lateral end of the clavicle

A

it rolls up

125
Q

the motion during ST motion of 60° causes posterior clavicular rotation at AC ,, which ligaments become taut and what does it prevent

A

coracoclavicualr (conoid and trapezoid) and costoclavicular lig become taut and prevents more elevation

126
Q

for ST upward rotation to occur there has to be a force couple of what muscles

A

upper trap , lower trap and SA

127
Q

what muscles are a force couple for ST upward rotation and also produce and control tipping and rotation during elevation

A

traps and SA

128
Q
A