Shoulder joints Flashcards
(122 cards)
1
Q
what is the shoulder complex
A
an ensemble of bones, joints and soft tissue that must function synchronously
2
Q
what is the center of activity and has dual function
A
GH joint
3
Q
what are the dual functions of the GH joint
A
stability and mobility
4
Q
what is the function of the shoulder
A
mobilize the hand in space
5
Q
what does the design of the shoulder allow
A
for a large ROM
but this mobility presents conflict
we also need stability
6
Q
articulation of the sternoclavicular joint
A
sternal end of the clavicle w/ the notch formed by the manubrium of the sternum and first costal cartilage
very incongruent joint
7
Q
how is the SC joint incongruent
A
the articular surface of the clavicle is thicker than the articular surface of the manubrium
8
Q
what type of joint is the SC joint
A
plane joint w/ 3 degrees of freedom of motion
although the joint is a plane joint, the surfaces are saddle shaped
9
Q
how does the clavicle present w/in the SC joint in the frontal plane
A
the clavicle is convex w/in the frontal plane
10
Q
how does the manubrium present w/in the SC joint in the anterior/posterior direction
A
the manubrium is convex w/in the anterior/posterior direction
11
Q
how does the clavicle present w/in the SC joint in the anterior/posterior direction
A
the clavicle is concave w/in the anterior and posterior direction
12
Q
how does the manubrium present w/in the frontal plane of the SC joint
A
the manubrium is concave w/in the frontal plane
13
Q
how’re the manubrium and clavicle separated w/in the SC joint
A
fibrocartilaginous disc
14
Q
what’re the functions of the sternoclavicular disc
A
- increase the motion b/w the articular surfaces
- acts as a shock absorber for forces that are transmitted from the lateral end of the clavicle
- improves joint stabilization by increasing joint congruity
15
Q
motions of the SC joint
A
elevation
depression
protraction
retraction
upward rotation
downward rotation
16
Q
elevation and depression occur
A
in the frontal plane around the sagittal axis
17
Q
approximately how much can the SC joint elevate
A
45 degrees
18
Q
approximately how much can the SC joint depress
A
5-15 degrees
19
Q
where does protraction and retraction occur for the SC joint
A
transverse plane around a superomedial to inferomedial oblique axis
20
Q
what is retraction @ the SC accompanied by
A
elevation
21
Q
what is protraction @ the SC joint accompanied by
A
depression
22
Q
(SC joint) protraction is the movement of
A
the distal clavicle anteriorly
23
Q
(SC joint) retraction is the movement of
A
the distal clavicle posteriorly
24
Q
how much pro/retraction can the SC perform
A
15 degrees
25
is rotation a true degree of freedom
no
26
where does rotation occur @ the SC joint
longitudinal axis of the clavicle
27
how does rotation occur (SC)
w/ elevation of the arm and w/ scapular rotation
28
what is upward rotation (SC)
anterior edge of the clavicle moving upwards
also called posterior rotation
29
what is downward rotation
anterior edge of the clavicle moving downwards
also called anterior rotation
30
how much upward rotation can the clavicle do (SC joint)
30-45 degrees
31
how much downward rotation can the clavicle do (SC joint)
10 degrees
32
elevation arthrokinematics (SC joint)
a convex clavicle moving on a concave manubrium
the bone motion and roll are in the same direction (up)
glide is in the opposite direction (down)
33
depression arthrokinematics (SC joint)
a convex clavicle moving on a concave manubrium
the bone motion and roll are in the same direction (down)
glide is in the opposite direction (up)
34
protraction arthrokinematics (SC joint)
a concave clavicle moving on a convex manubrium
bone motion, roll and glide are in the same direction anteriorly
35
retraction arthrokinematics (SC joint)
a concave clavicle moving on a convex manubrium
bone motion, roll and glide are in the same direction posteriorly
36
rotation arthrokinematics (SC joint)
primarily a spin motion
37
3 ligaments of the SC joint
anterior & posterior sternoclavicular ligaments
interclavicular ligament
costoclavicular ligament
38
anterior and posterior sternoclavicular ligaments
reinforce the joint capsule
39
interclavicular ligament
runs b/w the 2 clavicles
40
costoclavicular ligament
runs from the first rib to the clavicle
41
function of the ligaments during protraction
limited by costoclavicular ligament, posterior sternoclavicular capsule and ligament and posterior fibers of interclavicular ligament
movement of protraction is anterior, so limitation is posterior
42
function of the ligaments during retraction
limited by anterior fibers of costoclavicular ligament, anterior sternoclavicular capsule and ligament
movement is posterior so thinks that limit it will be anterior
43
function of the ligaments during elevation
limited by tension in the costoclavicular ligament, anterior sternoclavicular capsule and ligament
movement is upwards, limited by inferior factors
44
function of ligaments during depression
limited by interclavicular ligament and the superior capsule
movement is downwards, limited by superior factors
45
what is the AC joint
the articulation b/w the acromial end of the clavicle and the scapula
very incongruent
46
what type of joint is the AC joint
plane synovial joint
47
how many degrees of freedom does the AC joint have
3
48
articular surface shape of the AC joint
will vary
usually a convex/flattened distal clavicle and a concave acromion
49
what separates the 2 articular surfaces
fibrocartilaginous disk
varies in size
50
motions of the AC joint
rotation of the scap
winging of the scap
tilting/tipping of the scap
51
rotation of the scapula (AC joint)
upward and downward rotation
allows for the glenoid to rotate upward and downward
most important movement of the AC joint
occurs around an anteroposterior axis (AP)
**Rotation in the AC joint is IDENTICAL and synonymous to rotation in the scapulothoracic joint**
52
upward rotation of the scap (AC joint)
lateral rotation
ABD
53
downward rotation of the scap (AC joint)
medial rotation
ADD
54
winging of the scap (AC joint)
occurs around a vertical axis
describes the normal posterior movement of the vertebral border of the scapula (medial border moves away from the ribcage)
too much winging is not good
55
why is winging considered a normal movement (AC joint)
we need winging in order to have normal function
it helps the scapula stay in contact with and move around the thorax since the thorax is curved
so, winging allows for the scapula to move around the horizontally curvature of the thorax
56
tipping/tilting of the scapula (AC joint)
occurs around a frontal axis
visualized as the inferior angle of the scap moving posteriorly as the superior border of the scap moves anteriorly
57
what does tipping/tilting allow of the scapula (AC joint)
to maintain contact with the ribcage
58
what movements does tilting/tipping of the scap occur (AC joint)
elevation
depression
rotation of the clavicle
59
how much tilting/tipping of the scap do we have (AC joint)
estimated to be about 30 degrees
60
ligaments of AC joint
joint capsule
acromioclavicular ligaments
coracoclavicular ligaments
61
joint capsule (AC joint)
fairly weak
cannot maintain the integrity of the joint w/o ligamentous reinforcement
62
acromioclavicular ligaments
4 parts (anterior, posterior, inferior, superior)
63
what part of the acromioclavicular ligaments is the strongest
superior part
b/c it is reinforced by the aponeurosis of the trapezoid and deltoid
64
coracoclavicular ligaments
most important of the AC joint b/c it provides stability and mobility
2 parts (trapezoid and conoid)
not a direct anatomical part of the AC joint, but firmly attaches the clavicle to the scapula and provides stability
originate on the coracoid process and attach to the posterior edge of the clavicle
65
claviscapular link/claviscapular joint
the firm attachment of the coracoclavicular ligaments of the clavicle and scapula
66
most important function of the coracoclavicular ligaments
produce rotation of the clavicle that is necessary for full ROM in elevation of the upper extremity
67
explain elevation of the UE, in regards to the coracoclavicular ligaments
as the UE elevates --> the scapula upwardly rotates
this causes the coracoid process to move inferiorly, which pulls the coracoclavicular ligaments downward since they originate on the coracoid process
since the coracoclavicular ligaments attach to the posterior edge of the clavicle, it pulls down on it, so the clavicle posteriorly rotates
the result of the UE elevating is that the clavicle posteriorly rotates due to the pull of the coracoclavicular ligaments (clavicular rotation)
68
is the scapulothoracic joint a true anatomic joint
no
69
what are the articulations of the scapulothoracic joint
articulation b/w the scapula w/ the thorax
70
what are movements of the scap associated with at the scapulothoracic joint
motions of the SC joint and the AC joints
scapula --> clavicle (AC joint)
clavicle to the axial skeleton --> SC joint
71
where does the scapula lie
the scapular plane
72
what is the scapular plane
30-45 degrees in front of the coronal plane
73
why is the scapular plane important
for special tests on the shoulder joint and inspecting it
74
resting position of the scapula
reference point for scapular movement
on the posterior thorax
2 inches from the midline
lies b/w the 2nd and 7th ribs
75
why is resting position important
if the scapula starts in a different position, it can end in a different position
this causes everything to be in a different position
b/c everything is connected
76
are motions independent of each other?
no, although motions are described independently, they don't happen alone at the SC and AC joints
motions tend to occur together at varying degrees
77
elevation and depression of the scapulothoracic joint
translatory motion of the scap along the rib cage from the resting position
moving upward (elevation) and downward (depression)
estimated about 10-12 cm of motion
78
ABD and ADD of the scapulothoracic joint
translatory movement of the scap as it moves towards the vertebral column or away from it
towards (ADD), away (ABD)
estimated about 15 cm of motion
79
upward and downward rotation scapulothoracic joint
rotary motions of the scap that change the position of the glenoid fossa
**ROTATION AT THE AC JOINT IS IDENTICAL TO ROTATIONS AT SCAPULOTHORACIC JOINT**
80
upward rotation at scapulothoracic joint
inferior angle of the scap moving away from the midline
81
downward rotation at the scapulothoracic joint
inferior angle of the scap moving towards the midline
82
what will motion in one area cause
motion in another area
83
functions of the scapulothoracic joint
1. to orient the glenoid for optimal contact w/ the moving arm
2. Adds ROM to elevation of the arm
3. provide a stable base for controlling and gliding of the humeral head
84
ligaments of the scapulothoracic joint
superior transverse ligament
coracoacromial ligament
85
superior transverse ligament
converts the suprascapular notch into a foramen
suprascapular N passes under the lig
suprascapular vessels run over the lig
86
coracoacromial ligament
extends from the coracoid to the acromion
creates the subacromial space
87
what contents are w/in the subacromial space
supraspinatus
bursa
can cause subacromial crowding
88
what is subacromial crowding cause
impingement at the shoulder
89
what is the glenohumeral joint
articulation b/w the large head of the humerus w/ the small glenoid fossa
90
describe the humeral head and glenoid
humeral head is 2-3x larger than the glenoid
glenoid is very shallow
91
describe the GH joint
very mobile, but can be stable
92
is the GH joint congruent or incongruent
incongruent
may allow for increased mobility of the hand
93
how is the articular surface of the glenoid enhanced
glenoid labrum
increases the depth of the fossa
increases stability
94
what type of joint is the GH joint
ball and socket synovial
3 degrees of freedom
95
concave/convex GH joint
glenoid is concave and the humeral head is convex
the humeral head moves on the glenoid
bone motion and roll in the same direction, glide in the opposite direction
96
flexion of the GH joint
elevation
120 degrees
97
why can't the shoulder flex to 180 on its own
it needs the scapula thoracic relationship
this causes upward rotation of the scapula, which allows the shoulder to reach 180 degrees of flexion
98
extension of GH joint
55-60 degrees
99
flexion/extension GH joint
sagittal place around an x-axis
100
abduction/adduction GH joint
frontal plane around a sagittal axis (y-axis)
101
ABD GH joint
120 degrees
102
what else happens during GH ABD
ER of the humeral head
prevents the greater tubercle from hitting acromion
someone won't be able to ABD fully w/o ER
103
IR/ER GH joint
transverse plane around a vertical axis (z-axis)
IR: 70 degrees
ER: 90 degrees
104
arthrokinematics of GH joint
convex humeral head moving on a concave glenoid
bone motion and roll in the same direction
gliding in opposite direction
there is minimal translation or gliding of the humeral head on the glenoid
105
arthrokinematics flexion GH
bone motion and roll --> superior and anterior
glide--> inferior and posterior
106
arthrokinematics extension GH
bone motion and roll --> inferior and posterior
glide --> anterior
107
arthrokinematics ABD GH
bone motion and roll --> superior
glide --> inferior
108
arthrokinematics ADD GH
bone motion and roll --> inferior
glide --> superior
109
arthrokinematics ER GH
bone motion and roll --> posterior
glide --> anterior
110
arthrokinematics IR GH
bone motion and roll --> anterior
glide --> posterior
111
ligaments of the GH joint
capsule
glenohumeral ligaments
coracohumeral ligament
112
capsule GH
completely encircles the GH joint articulation
thickest in its superior and inferior extents (relatively loose and redundant)
laxity of the capsule is necessary for large excursion of joint surfaces
provides little stability w/o reinforcement from ligaments and muscles
113
glenohumeral ligaments
reinforce the anterior capsule
3 parts (superior, middle, inferior)
form a "Z" on the anterior capsule
may assist in capsular thickening
all portions tighten with ER
injury to these ligaments decrease stability of the joint
114
what portion is the strongest of the glenohumeral ligaments
inferior
primary structure that provides anterior stability for the GH joint
115
how do the glenohumeral ligaments tighten with ER
help stabilize ER
gliding occurs anteriorly during ER
3 ligaments stop over-glide
116
coracohumeral ligament
extend from base of coracoid to greater and lesser tuberosities
limit lateral rotation of the humerus
provides passive support of the arm against the force of gravity
117
what are the primary stabilizers of the shoulder
muscles
118
4 general structures that are main factors of stability of the GH joint
1. articular
2. labrum
3. capsulolabrum complex
4. rotator cuff
119
articular GH stability
d/t shape and torsion of humeral head and mobility of the scap
design of the joint does add to some stability
120
capsulolabrum complex
capsule and GH ligaments
121
rotator cuff
dynamic stabilization
122
what is necessary for full ROM
all different motions at all 4 shoulder joints
will combine to have smooth shoulder motion
scapulohumeral rhythm
