Shoulder Flashcards
(186 cards)
1
Q
What are the 4 joints of the shoulder complex?
A
Sternoclavicular (SC)
Acromioclavicular (AC)
Scapulothoracic (ST)
Glenohumeral (GH)
2
Q
What are the kinematics of the SC joint?
A
elevation and depression (frontal plane)
protraction and retraction (horizontal plane)
posterior clavicular rotation (sagittal plane)
3
Q
What are the kinematics of the SC joint during elevation?
A
superior roll, inferior slide
AP AOR
stretched costoclavicular ligament produces downward force in direction of slide
4
Q
What are the kinematics of the SC joint during depression?
A
inferior roll, superior glide
AP AOR
5
Q
What are the kinematics of the SC joint during retraction?
A
vertical AOR throught sternum
concave on convex: roll and slide both in posterior direction
6
Q
What are the kinematics of the SC joint during protraction?
A
vertical AOR throught sternum
concave on convex: roll and slide both in anterior direction
7
Q
What are the primary motions of the AC joint?
A
upward and downward rotation
AP AOR
8
Q
What are the secondary motions of the AC joint?
A
internal and external rotation, anterior and posterior tilting
9
Q
What are the motions of the Scapulothoracic Joint?
A
elevation and depression, protraction and retraction, upward and downward rotation
10
Q
What motions compose Scapulothoracic Elevation?
A
elevation (upward rotation) of SC joint: superior roll, inferior glide
downward rotation at AC joint
11
Q
What motions compose Scapulothoracic protraction?
A
Protraction (anterior roll and anterior slide) at SC joint
horizontal place adjustments at AC joint
12
Q
What motions compose Scapulothoracic upward rotation?
A
SC joint elevation (superior toll, inferior slide)????
AC upward rotation
13
Q
What motions compose Scapulothoracic depression?
A
depression at SC joint: inferior roll, superior slide + upward rotation at AC joint
14
Q
What motions compose Scapulothoracic retraction?
A
retraction at SC joint: posterior roll, posterior slide + slight horizontal plan adjustments of AC joint
15
Q
What motions compose Scapulothoracic downward rotation?
A
depression of SC joint: interior roll, superior slide + downward rotation at AC joint
16
Q
What 3 important functions do upward rotation of scapula during full shoulder abduction in plane of scapula serve?
A
- projects glenoid fossa upward and anterior-laterally, providing structural base to maximize upward and lateral reach of upper limb
- preserves optimal length-tension relationship of abductor muscles of GH joint, such as middle deltoid and supraspinatus
- helps maintain volume within subacromial space
17
Q
How much articular surface does the glenoid fossa cover?
A
About 1/3 of articular surface of humeral head
18
Q
In what positions is most excessive motions in an instable GH joint?
A
anteriorly and inferiorly
19
Q
What are the primary motions drawing the middle glenohumeral ligament taut?
A
Anterior translation of the humeral head, especially in about 45-60° of abduction; external rotation
20
Q
What are the primary motions drawing the Inferior glenohumeral ligament (three parts: anterior band, posterior band, and connecting axillary pouch)?
A
Axillary pouch: 90° of abduction, combined with anterior-posterior and inferior translations
Anterior band: 90° of abduction and full external rotation; anterior translation of humeral head
Posterior band: 90° of abduction and full internal rotation
21
Q
GIRD is indicated by what?
A
20° or greater loss of internal rotation of throwing shoulder compared with non-dominant shoulder
22
Q
What are some common findings in overhead athletes?
A
Associated with GH and scapulothoracic deficiency
Associated with rotator cuff tears and labral pathology
23
Q
What are primary motions drawing superior glenohumeral ligament taut?
A
Adduction, inferior and anterior-posterior translation of humeral head
24
Q
What are primary motions drawing coracohumeral ligament taut?
A
Adduction; inferior translation of the humeral head; external rotation
25
What are the osteokinematics of the GH joint?
abduction and adduction, flexion and extension, internal and external rotation
26
What are the kinematics of the GH joint during abduction?
inferior slide, superior roll, AP AOR, longitudinal diameter
27
What are the kinematics of the GH joint during adduction?
superior slide, inferior roll, AP AOR, longitudinal diameter
28
What are the kinematics of the GH joint during external rotation?
anterior slide, posterior roll, Horizontal plane/vertical AOR, transverse diameter
29
What are the kinematics of the GH joint during internal rotation?
posterior slide, anterior roll; Horizontal plane/vertical AOR, transverse diameter
30
What are the kinematics of the GH joint during flexion?
anterior spin, Near sagittal plane/near ML AOR
31
What are the kinematics of the GH joint during extension?
posterior spin, Near sagittal plane/near ML AOR
32
What is kinematics?
branch of mechanics that describes the motion of a body, without regard to the forces or torques that may produce the motion; assessed by goniometer and accelerator etc
33
What is kinetics?
branch of mechanics that describes the effect of forces and torques on the body as measured by transducer etc.
34
What is a moment arm?
perpendicular distance between an axis of rotation and the line of force.
35
What is torque?
a force multiplied by its moment arm; tends to rotate a body or segment around an axis of rotation, hence rotary force.
36
What is internal force?
push or pull produced by a structure located within the body. Most often, internal force refers to the force produced by an active muscle.
37
What is internal/external torque?
product of an internal/external force and its internal/external moment arm.
38
What is joint reaction force?
force that exists at a joint, developed in reaction to the net effect of internal and external forces.
39
What is mechanical advantage?
ratio of the internal moment arm to the external moment arm or of the output force to the input force.
40
Class 1 Lever
Fulcrum in the middle; MA can be greater/less/equal to 1. Designed for speed and range of motion
41
Class 2 Lever
Resistance in the middle; MA is greater than 1. Has advantage in force
42
Class 3 Lever
Effort in the middle; MA is less than 1. Has advantage in speed and range of motion
43
Functional design of Class 1 lever with axis near the middle:
Balanced movements
44
Functional design of class 1 lever with axis near force
speed and range of motion
45
Functional design of class 1 lever with near resistance
force/strength
46
Functional design of class 2 lever with axis near resistance
force/strength
47
Functional design of class 3 lever with axis near force
speed and range of motion
48
What is translation?
describes linear motion in which all parts of rigid body move parallel to and in same direction as every other part of body. Can occur in straight or curved line
49
What is rotation?
describes motion in which assumed rigid body moves in circular path around some pivot point. All points in body simultaneously rotate in same angular direction across the same number of degrees.
50
What are active movements?
caused by stimulated muscle, such as lifting glass of water toward mouth
51
What are passive movements?
caused by sources other than active muscle contraction, such as a push from another person, the pull of gravity, tension in stretched connective tissues, and so forth
52
What movements occur in the sagittal plane?
Flexion and extension
| Dorsiflexion and plantar flexion
53
What movements occur in the frontal plane?
Abduction and adduction
| Lateral flexion
54
What movements occur in the horizontal plane?
Internal (medial) and external (lateral) rotation
55
What is the axis of rotation of flexion and extension?
medial-lateral axis of rotation
56
What is the axis of rotation of abduction and adduction?
anterior-posterior axis of rotation
57
What is the axis of rotation of internal and external rotation?
vertical axis of rotation
58
What is degrees of freedom for a joint?
number of independent directions of movements allowed at a joint
59
How many degrees of freedom can joints have?
Joint can have up to three degrees of angular freedom, corresponding to three cardinal planes
60
What is a roll?
Multiple points along one rotating articular surface contact multiple points on another articular. Example: A tire rotating across a stretch of pavement
61
What is a slide/glide?
A single point on one articular surface contacts multiple points on another articular surface. Example: A non-rotating tire skidding across a stretch of icy pavement
62
What is a spin?
A single point on one articular surface rotates on a single point on another articular surface.. Example: A toy top rotating on one spot on the floor
63
Convex on cave movement occurs in what direction?
opposite direction
64
Concave on convex movement occurs in what direction?
the same direction
65
What is a closed pack position?
most ligaments and parts of capsule pulled taut providing stability to joint. Accessory movements typically minimal in close-packed position
-maximum contact between surfaces
66
What is loose packed position?
ligaments and capsule relatively slackened allowing increase in accessory movements. Joint generally least congruent near its midrange
67
The stress-strain curve changes as a function of:
Time of loading
| Rate of loading
68
What is creep?
Creep describes progressive strain of material when exposed to constant load over time
-reversible
69
What two outcomes can forces have on the body?
- Translate a body segment
| - produce potential rotation of joint
70
What is the moment arm?
perpendicular distance between axis of rotation and force
71
A muscle is capable of producing torque at a joint only if:
- produces a force in plane perpendicular to AOR of interest
| - acts with associated moment arm distance greater than zero
72
External torque equals internal torque:
isometric activation; no muscle shortening or rotation at joint
73
Internal torque is greater than external torque
```
concentric activation (muscle contracts/shortens)
creates rotation of joint in direction of pull of activated muscle
```
74
External torque is greater than internal torque
Eccentric activation: muscle produces pulling force as it is being elongated by another dominant force
75
Osteoblasts:
cells that create bone
76
Osteoclasts
cells that reabsorb bone
77
cortical
compact, very dense, outer later
78
cancellous
spongy, very porous, inner layer
79
Types of bone:
1. long (ulna, clavicle, femur)
2. short (tarsals, carpals)
3. flat (ribs, scapula, sternum)
4. Irregular (skulls, vertebrae)
5. sesamoid (patella)
80
Wolff's Law
```
Resorption
-response to decreased stree
-osteoclasts dominate
-disue, immobilization
Deposition
-response to increased stress
-osteoblasts dominate
-weight bearing exercise
```
81
Osteoporosis
resorption exceeds deposition
82
Anisotropic
response depends on direction of load application
83
Visoelastic
response depends on rate & duration of loading
84
Elastic response
deformation in response to loading
| load removed -return to original shape/length
85
Plastic response
microtears & debonding
| load removed- permanently deformed
86
Failure is caused by
- single traumatic event
| - accumulation of microfractures
87
Types of loading
1. compression
2. tension
3. shear
4. bending
5. torisonal
88
Compression
presses ends of bones together
89
Tension
pulls or stretches bone apart
90
Shear
parallel to the surface of object
91
Bending
applied to area having no direct support
92
Torsional
twisting force
93
Two types of cartilage
1. articular
| 2. fibrocartilage
94
Fibrocartilage
- improves fit between bones
| - intermediary between hyaline cartilage and other connective tissue
95
Articular cartilage
- aka hyaline
- converts joints ends at articulations
- contains collage & proteoglycan
- 60-80% water
96
Ligaments connect what?
bone to bone
97
Ligaments consist of:
1. collagen
2. elastin
3. reticulin
98
What happens to ligaments during loading?
ligaments become stronger and stiffer
99
Where is arthritis seen?
in articular cartilage
100
What is joint stability created by?
- ligaments
- gravity
- vacuum
101
What joints are typically most stable?
synovial joint
102
What is a simple joint?
connects two articulating surfaces
103
What is a compound joint?
connects three or more articulating surfaces
104
What is a complex joint?
connects two surfaces with articular disc or fibrocartilage
105
What is an example of closed -packed position?
full extension at knee
106
What are the functions of muscle?
- produce movement
- maintain postures & positions
- stabilize joints
- support & protect visceral organs
- alter & control cavity pressure
- maintain body temperature
- control entrances/exits to body
107
prime mover
muscle(s) primarily responsible for a given movement
108
assistant mover
other muscles contributing to movement
109
agonist
muscles creating same joint movement
110
antagoinst
muscles opposing joint movement
111
stabilizer
holds one segment still so specific movement in an adjacent segment can occur
112
neutralizer
muscle working to eliminate undesired joint movement of another muscle
113
belly
thick central portion
114
epimysium
outside covering of a muscle
115
fascicles
bundles of muscle fibers
116
perimysium
dense connective sheath covering a fasicle
117
fibers
cells of a skeletal muscle
118
endomysium
very fine sheath covering individual fibers
119
sarcolemma
thin plasma membrane branching into muscle
120
myofibrils
- rodlike strands of contractile filaments
| - many sarcomeres in series
121
sacroplasma
cytoplasm of muscle cell
122
sarcoplasmic reticulum
speacialized endoplasmic reticulum of muscle cells
123
T-tubules
extension of sarcolemma that protrudes into muscle cell
124
myosin
thick, dark filament
125
actin
thing, light filament
126
sacromere
unit of myosin an actin
| contractile unit of muscle
127
Fibers run in what direction in fusiform muscles
parallel to each other and central tendon
128
Fibers run in what direction in pennate muscles
approach central tendon obliquely = more fibers into a given length of muscle=large cross sectional area and higher capability for generating force
129
PEC
parallel elastic component
allows the muscle to be stretched
associated with fascia surrounding muscle
130
Contractile
converts stimulation into force
131
SEC
series elastic
| transfers muscle force to bone
132
critical length
muscle begins to generate passive tension
133
Henneman Size Principle
smaller neurons generally recruited before larger motor neurons
134
Type I Fiber
slow twitch, oxidative
red (high myoglobin)
endurance athletes
135
Type IIA Fiber
intermediate fast-twitch, oxidative-glycolytic
136
Type IIX Fiber
fast twitch, white
glycolytic
sprinters
137
Muscles attach to bone:
1. directly
2. via a tendon
3. via an aponeurosis
138
Tendon
inelastic bundle of collagen fibers
139
Aponeurosis
sheath of fibrous tissue
140
Characteristics of a Tendon
1. transmits muscle fore to associated bone
2. Can withstand high tensile loads
3. Visoelastic stress-strain response
4. myotendinous junction (where tendon and muscle join)
141
Principle 1
Based on generalized 2 : 1 scapulohumeral rhythm, active shoulder abduction of about 180° occurs as result of simultaneous 120° GH joint abduction and 60° of scapulothoracic upward rotation.
142
Principle 2
60° of upward rotation of scapula during full shoulder abduction is result of simultaneous elevation at SC joint combined with upward rotation at AC joint.
143
Principle 3
Clavicle retracts at SC joint during shoulder abduction.
144
Principle 4
Scapula posteriorly tilts and externally rotates during full shoulder abduction.
145
Principle 5
Clavicle posteriorly rotates around its own axis during shoulder abduction.
146
Principle 6
GH joint externally rotates during shoulder abduction.
147
What is SICK scapula?
S=scapular malposition
I=inferior medial border prominence
C=coracoid pain and malposition
K=dykinesis of the scapula
148
What are the three types of dykinesis?
Type I: Inferior medial scapular prominence
Type II: Medial scapular border prominence
Type III: Superomedial border prominence
149
Type I and II dyskinesis associated with what?
SLAP lesions
150
Type III associated with what?
impingement and rotator cuff lesion
151
Dyskinesis shows what compared to normal patients?
Dyskinesis showed less scapular upward rotation, less clavicular elevation, and greater clavicular protraction
152
What are the two categories of muscles of the shoulder complex?
proximal stabilizers and distal mobilizers
153
Proximal stabilizers
originate on spine, ribs and cranium and insert on scapula and clavicle
154
Distal mobilizers
originate on scapula and clavicle and insert on humerus and forearm
155
What are the elevators for the ST joint?
Upper trapezius
Levator scapulae
Rhomboids
156
What are the depressors of the ST joint?
Lower trapezius
Latissimus dorsi
Pectoralis minor
Subclavius
157
What are the categories of muscles of the STJ?
elevator or depressor, protractor or retractors, upward and downward rotators
158
What are the protractors of the STJ?
-serratus anterior
159
What are the retractors of the STJ?
Middle trapezius
Rhomboids
Lower trapezius
160
What are the upward rotators of the STJ?
Serratus anterior
| Upper and lower trapezius
161
What are the downward rotators of the STJ?
Rhomboids
| Pectoralis minor
162
What is the function of the elevators?
support posture of shoulder girdle (scapula and clavicle) and upper extremity
163
When are all retractors active?
during pulling activities
164
Complete paralysis of the trapezius reduces what?
retraction potential of the scapula
165
What are the three categories elevators fall into?
1. muscles that elevate (abduct or flex) at the GH joint
2. scapular muscles that control upward rotation of SC joint
3. rotator cuff muscles that control dynamic stability & arthokinematics at GH joint
166
What are the GH joint muscles primarily responsible for elevation of arm?
Anterior and middle deltoid
Supraspinatus
Coracobrachialis
Biceps (long head)
167
What are the STJ muscles responsible for elevation of arm?
Serratus anterior
| Trapezius (upper & lower)
168
What are the rotator cuff muscles primarily responsible for elevation of arm?
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
169
Supraspinatus _________ humeral head _________ toward abduction while also compressing joint
rolls, superiorly
170
Subscapularis, infraspinatus, and teres minor exert ___________ force on humeral head to counteract excessive superior translation, especially that caused by deltoid contraction
downward translational
171
What does the supraspinatus do during abduction?
Drives superior roll of humeral head
Compresses humeral head firmly against glenoid fossa
Creates semi-rigid spacer above humeral
172
What does the infraspinatus, teres minor and subscapularis do during abduction?
Exert depression force on humeral head
173
What does the infraspinatus and teres minor do during abduction?
externally rotate humerus
174
What are direct or indirect causes of impingement syndrom
1. Abnormal kinematics at GH and scapulothoracic joints (STJs)
2. “Slouched” posture affecting alignment of STJ
3. Fatigue, weakness, poor control, or tightness of muscles that control GH or STJ motions
4. Inflammation and swelling of tissues within and around subacromial space
5. Excessive wear and subsequent degeneration of tendons of rotator cuff muscles
6. Instability of GH joint
7. Adhesions within inferior GH joint capsule
8. Excessive tightness in posterior capsule of GH joint (and associated anterior migration of humeral head toward lower margin of coracoacromial arch)
9. Osteophytes forming around AC joint
10. Abnormal shape of acromion or coracoacromial arch
175
What are theFour Articulations within Elbow
and Forearm Complex?
Humero-ulnar joint
Humeroradial joint
Proximal radio-ulnar joint
Distal radio-ulnar joint
176
What provides most of the elbow's structural stability?
Tight fit b/w trochlea and trochlear notch at humero-ulnar joint
177
What causes the medial/lateral axis of the elbow to course slight superiorly?
owing in part to distal prolongation of medial lip of trochlea
This asymmetry in trochlea causes ulna to deviate laterally relative to humerus
178
What is a valgus angle?
Natural frontal plane angle made by extended elbow
179
What can excessive cubitus valgus damage by overstretching?
ulnar nerve
180
What do collateral ligaments do for the elbow?
provide stability?
181
What does the medial collateral ligaments consist of?
anterior, posterior, and transverse fibers
| anterior fibers are strongest and stiffest
182
What do the collateral ligaments resist against?
valgus (abduction) force to elbow
183
Where do the anterior fibers of medial collateral ligament arise and insert?
arise from anterior part of medial epicondyle and insert on medial part of coronoid process of ulna
184
Where do posterior fibers of MCL arise and insert?
Posterior fibers attach on posterior part of medial epicondyle and insert on medial margin of olecranon process
Posterior fibers resist valgus force, as well as become taut in extremes of elbow flexion
185
Where do the transverse fibers of the MCL arise and insert?
olecranon to coronoid process of ulna
| Because these fibers originate and insert on same bone, they do not provide significant articular stability
186
Paralysis of serratus anterior can occur from injury to what?
long thoracic nerve, spinal cord, cervical nerve root
