Exam II Flashcards
(460 cards)
1
Q
what are the 3 true joints of the shoulder? what are the 2 articulations of the shoulder?
A
True Joints (1) GH joint (2) AC joint (3) SC joint Articulations (1) Scapulothoracic (2) Suprahumeral articulation
2
Q
the head of the humerus is much larger than the glenoid fossa, as a result what is the shoulder prone to?
A
instability; dislocations
3
Q
what covers the glenoid cavity?
A
the labrum
4
Q
what is the purpose of the labrum? (2)
A
(1) deepens the cavity
2) creates a negative pressure inside the cavity (like a suction cup
5
Q
what angle is the humeral head at in the glenoid cavity?
A
30 degrees of retroversion; angled between frontal and sagittal planes
6
Q
what sports might you see an increased amount of retroversion?
A
overhead throwing sports, such as baseball
7
Q
what is the closed pack position of the GH joint?
A
90 degrees abduction, full ER
8
Q
what is the open pack position of the GH joint?
A
40-50 degrees of abduction, 30 degrees of horizontal adduction
9
Q
how does an increased retroversion of the shoulder affect ROM?
A
increased retroversion leads to increased ER at the GH joint; also leads to decreased IR (GIRD)
10
Q
what are the passive mechanisms that provide stability to the GH joint? (4)
A
(1) capsule, ligaments, labrum, and tendons
(2) posture
(3) negative intracapsular pressure
(4) acromion (prevent superior subluxation)
11
Q
how does poor posture contribute to GH instability?
A
forward shoulder posture can cause downward rotation of the GH joint causing ligament laxity; can also cause the humerus to travel superiorly
12
Q
what attaches to the glenoid labrum?
A
the biceps tendon; about 50% of the tendon fibers attach to labrum
13
Q
why are baseball players more prone to SLAP tears?
A
the biceps tendon works to decelerate the arm in throwing motions, increasing risk of labral tears
14
Q
what is one reason a SLAP tear causes decreased stability of the GH joint?
A
tearing the labrum causes a decrease of negative pressure in the joint
15
Q
what is a bankart lesion? what is typically the cause?
A
tear of anterior-inferior labrum (often with fracture of glenoid rim); usually caused by anterior dislocation or fracture
16
Q
what are the movements that accompany GH abduction?
A
(1) inferior glide
(2) external rotation
17
Q
what are the movements that accompany GH adduction?
A
(1) superior glide
(2) internal rotation
18
Q
what are the movements that accompany GH external rotation?
A
(1) anterior glide
19
Q
what are the movements that accompany GH internal rotation?
A
(1) posterior glide
20
Q
what are the movements that accompany GH flexion?
A
(1) external rotation
(2) inferior glide
21
Q
what are the movements that accompany GH extension?
A
(1) internal rotation
(2) inferior glide
22
Q
with elevation of the humerus, which position puts the least amount of stress on the joint?
A
scaption (not pure flexion or pure abduction)
23
Q
other than it’s muscle actions, what is the main role of the supraspinatus?
A
prevents superior translation of the humeral head
24
Q
what can happen if the supraspinatus is torn or injured?
A
it can’t effectively prevent superior translation of the humerus, which can result in subacromial impingement
25
what is the normal space between the humerus and acromion in a resting position?
10-12 mm
26
what is the GH joint designed for?
mobility; NOT stability
27
how much retroversion do baseball players tend to have?
45 degrees
28
during shoulder elevation, what range is subacromial space the smallest?
60-80 degrees
29
what type of joint is the SC joint?
a saddle joint
30
how would you describe the surfaces of the SC joint?
Frontal Plane
-A convex clavicle moves on a concave sternum
Sagittal Plane
-A concave clavicle moves on a convex sternum
31
why is arthritis uncommon at the SC joint?
it has a fibrocartilage disc between the clavicle and sternum that absorbs shock
32
when protraction/retraction occurs, which way are the roll and glides at the SC joint?
the roll and glide occur in the same direction (sagittal plane movement)
33
when elevation/depression occurs, what way does the SC joint glide?
Elevation (frontal plane)
-inferior glide
Depression (frontal plane)
-superior glide
34
when raising the arm overhead, which way does the clavicle rotate?
superior aspect of the clavicle rotates posteriorly 20-35 degrees; clavicle rotates back when arm is returned to side
35
which joint contributes more to scapular motion, the AC joint or SC joint?
SC joint
36
what injuries are common at the AC joint? what sports are these injuries most likely to occur?
dislocations and instability are most common; contact sports (ex. football or rugby)
37
can damage to the SC joint be fixed by exercise?
no because to muscles hold the SC joint in place
38
do passive or active structures most contribute to the stability of the AC joint?
passive; mainly ligaments, but the deltoids and upper traps play a small role
39
what is the most important ligament to the stability of the AC joint? why?
coracoclavicular ligament; stronger and absorbs more energy than other ligaments of the shoulder
40
what is the main function of the coracoclavicular ligament?
prevent posterior rotation and subluxation of the clavicle
41
what is the difference between a joint and an articulation?
a joint has cartilage between bones, while an articulation doesn't (ex. ST joint is an articulation)
42
where does the ST joint articulate?
between the scapula and ribcage
43
how many degrees of freedom does the ST joint have? what are they?
3 DOF
(1) anterior/posterior tilt
(2) IR / ER
(3) upward/downward rotation
44
**what happens at the SC and AC joints during ST joint elevation?** (2)
(1) Elevation at the SC joint
(2) Downward rotation at the AC joint
**Test Question**
45
what happens at the SC and AC joints during ST joint protraction? (2)
(1) protraction of the SC and AC joints
| (2) internal rotation of the AC joint
46
what happens at the SC and AC joints during ST joint upward rotation? (2)
(1) elevation of the SC joint
| (2) upward rotation of the AC joint
47
**what are the main functions of the ST joint?** (3)
(1) position the glenoid (upwardly rotated) so the shoulder functions properly
(2) maintain the length/tension relationship between delt and supraspinatus
(3) preserve subacromial space
48
what joints of the shoulder don't follow the concave/convex rule?
AC joint and ST joint
49
how many degrees of freedom does the SC joint have? what are they?
3 DOF
(1) protraction / retraction
(2) elevation / depression
(3) anterior / posterior rotation (less discussed, not a 'major' movement)
50
what is responsible for ST joint mobility?
ST joint movement is the result of movement at the AC and SC joints
51
what is scapulohumeral (SH) rhythm?
the coordinated motion of the humerus and scapula during elevation (flexion, scaption, abduction)
52
what is the ratio of humeral motion to scapular motion? (1st Kinematic Principle of Abduction)
2:1 (120 degrees of GH abduction to 60 degrees of scapular upward rotation)
53
what creates the 60 degrees of scapular upward rotation? (2nd Kinematic Principle of Abduction)
(1) elevation of the SC joint
(20-35 degrees from posterior rotation of the SC joint)
(2) upward rotation of the AC joint (30 degrees)
54
how much does the clavicle retract during full abduction?
| 3rd Kinematic Principle of Abduction
15-20 degrees
55
during full shoulder abduction what occurs with the tilt and rotation of the scapula? (4th Kinematic Principle of Abduction)
(1) posteriorly tilts (20 degrees)
| 2) externally rotates (0-5 degrees
56
how is the clavicle rotated posteriorly during full abduction? (5th Kinematic Principle of Abduction)
(1) as the serratus anterior upwardly rotates the scapula, which pulls the coracoclavicular ligament tight
(2) this causes the clavicle to rotate posteriorly around it's own axis
(3) this causes the AC joint to allow full upward rotation
57
when an arm is fully abducted or flexed to 180 degrees, how much ER is observed at the GH joint? why does this ER occur? (6th Kinematic Principle of Abduction)
40 degrees; allows the greater tubercle to pass posterior to the acromion to avoid impingement of the greater tubercle in the subacromial space
58
what are 2 ways motion in the scapular plane is more beneficial than movement in the frontal or sagittal plane?
(1) prevents subacromial impingement
| (2) reduces stress on the labrum
59
what population of patients would motion in the scapular plane be recommenced for?
(1) after capsular shift surgeries
(2) after labral repairs
(3) after shoulder surgery
60
what is the neutral position of the shoulder?
30 degrees retroversion
61
where do most of the proximal stabilizers and distal mobilizers insert?
(1) proximal stabilizers insert on the scapula and clavicle
| (2) distal mobilizers insert on the humerus or forearm
62
what do the proximal stabilizers and distal mobilizers act on?
(1) proximal stabilizers act on the AC, SC, and ST joints
| (2) distal mobilizers act on the GH joint
63
what muscles may act as both proximal stabilizers and distal mobilizers? (2)
(1) serratus anterior
| (2) traps
64
what are the proximal stabilizers that elevate the ST joint? (3)
(1) upper traps
(2) levator scapulae
(3) rhomboids
65
what are the proximal stabilizers that depress the ST joint? (4)
(1) lower traps
(2) lats
(3) pec minor
(4) subclavius
66
**what muscles are involved with raising the body from a chair to another surface?**
the depressors (think what muscles would work if your triceps didn't function)
**Test Question**
67
what are the proximal stabilizers that protract the ST joint? (1)
serratus anterior
68
what are the proximal stabilizers that retract the ST joint? (3)
(1) middle traps
(2) rhomboids
(3) lower traps
- the rhomboids and lower traps work synergistically to cause retraction; they have opposing vectors
69
**what are the proximal stabilizers that upwardly rotate the ST joint?** (3)
(1) serratus anterior
(2) upper traps
(3) lower traps
- all muscles working synergistically
70
what are the proximal stabilizers that downwardly rotate the ST joint? (2)
(1) rhomboids
| (2) lats
71
what are the distal mobilizers that abduct the GH joint? (2)
(1) deltoid (anterior and middle)
| (2) supraspinatus
72
what are the distal mobilizers that adduct the GH joint? (4)
(1) infraspinatus
(2) teres major
(3) deltoid (posterior)
(4) triceps (long head)
73
what are the distal mobilizers that elevate the GH joint? (6)
(1) deltoid (anterior and medial)
(2) coracobrachialis
(3) biceps
(4) all 4 rotator cuff muscles
- Both Proximal Stab / Distal Mob
(1) serratus anterior
(2) traps
74
what distal mobilizers assist with upward rotation of the ST joint?
abductors
75
what distal mobilizers assist with downward rotation of the ST joint?
adductors
76
what is the rotator cuff's function during arm elevation?
(1) tighten capsule to improve stability of GH joint
(2) compress humeral head against fossa
(3) controls active arthrokinematics of the GH joint
77
when the arm is elevated, it also externally rotates. why is this a more unstable position?
because it moves the RC tendons to a more lateral and posterior position, leaving the anterior shoulder more unstable (think about cocking back to throw a baseball)
78
below 90 degrees of elevation, what is mainly responsible to stability of the GH joint? what about above 90 degrees?
(1) below 90 degrees, the rotator cuff is mainly responsible for stabilizing the GH joint
(2) above 90 degrees, the capsule and ligaments are mainly responsible for stabilizing the GH joint (with assistance from RC)
79
what is an obligate translation?
when capsule and ligaments are tight in one direction and cause translation in the opposite direction (ex. tight posterior capsule causes humeral head to translate anteriorly during IR)
80
when a capsule is tight that causes obligate translations, what can occur?
obligate translations can cause laxity and instability of the capsule in the opposite direction of capsular tightness; can also cause impingement
81
what are 3 functions of the supraspinatus with regard to controlling arthrokinematic movement?
(1) drives the superior roll of the humeral head
(2) compresses the humeral head against the fossa
(3) resists excessive superior translation of the humerus
82
what is the function of the infraspinatus, teres minor, and subscap with regard to controlling arthrokinematic movement?
exert a depressive force on the humeral head
83
weakness of what muscles may lead to abnormal arm elevation?
(1) traps
| (2) RC muscles
84
the adductors and extensors often act in combination, what muscles adduct and extend the arm?
(1) lats
(2) teres major
(3) deltoid (posterior)
(4) triceps (long head)
(5) pec major (sternal head)
85
**what are the strongest muscles of the shoulder?**
adductors and extensors (should make sense if you think of muscle bulk)
86
what muscles are often utilized by paraplegic patients with bilateral crutches?
adductors and extensors because they're strong muscles
87
what are the distal mobilizers that internally rotate the GH joint? (5)
(1) subscap
(2) pec major
(3) lats
(4) teres major
(5) anterior delt
88
are internal rotators or external rotators of the shoulder stronger? why?
internal rotators are stronger; they have larger cross sectional areas
89
what are the distal mobilizers that externally rotate the GH joint? (3)
(1) infraspinatus
(2) teres minor
(3) posterior deltoid
- the supraspinatus acts as an ER when shoulder is flexed
90
where do the external rotators all attach?
between the scapula and humerus
91
if the scapular stabalizers are weak, what happens to the scapula during ER?
the scapula will wing because the external rotators are stronger than the scapular stabilizers, thus they pull the scapula off the rib cage
92
why doesn't winging happen with internal rotation?
because internal rotators attach to the scapula and the trunk, so they act as scapular stabilizers
93
why do high velocity throwing sports, such as baseball, lead to tears of the infraspinatus and teres minor?
those muscles are required to eccentrically contract at high velocities (eccentric deceleration at the end of a throw)
94
what are the weakest muscles of the shoulder?
(1) external rotators (weakest)
| (2) internal rotators
95
what are the two types of scapular dyskinesis?
(1) dysrhythmia: excessive elevation or protraction, non-smooth motion with elevation
(2) winging: medial border of the scapula are posteriorly displaced away from the thorax
96
what is the most common cause of scapular dyskinesia?
dysfunction of the proximal stabilizers of the shoulder
97
what are the 3 types of GH instability?
(1) acquired: repetitive high velocity motions with extreme ER and ABD; internal impingement
(2) atraumatic: uni or multidirectional; responds well to PT
(3) post-traumatic: (fall or collision; often injures cuff, anterior-inferior rim of the glenoid and labrum
98
what is the most common disorder of the shoulder?
subacromial impingement
99
what tissues are most commonly affected with subacromial impingement?
supraspinatus, biceps long head, superior capsule, subacromial bursa
100
what is the mechanical disadvantage of the supraspinatus?
1:20
101
what are the two types of osteokinematic motion?
spin and swing
102
what is the difference between spin and swing? which is more common?
spin occurs in one plane and swing occurs in multiple planes; swing occurs in 99% of motion (most motion occurs in multiple planes); spin is linear and swing is angular motion
103
what are some examples of when spin occurs?
during brief moments of shoulder flexion, hip flexion and pronation at the proximal radio-ulnar joint
104
what is the only joint of the spine that follows the concave/convex rule?
the atlanto-occipital joint
105
what is the difference between open and closed kinematic chain?
close chain: distal end of the kinetic chain is fixed (ex. squat, pull-ups)
open chain: distal end of the chain is free (ex. knee extensions, biceps curls)
106
what type of exercises are more functional and more optimal for strengthening the lower extremity?
closed-chain
107
what are the differences between the closed and open packed positions?
closed pack: excellent congruency (stress evenly distributed), least joint space, capsule tight
loose pack: poor congruency, joint space maximized, loose capsule
108
what position is a joint most stable, open or closed pack?
closed pack
109
what is the purpose of the elbow angle?
it's a carrying angle, so it allows us to carry things without bumping into LE
110
what is the average elbow or carrying angle?
15 degrees
111
how does elbow angle vary between gender, age, and height?
(1) females have wider angles due to having wider hips
(2) the angle gets larger as you age
(3) larger in shorter people (ASK LADIRA)
112
what is considered excessive valgus and varus at the elbow?
excessive valgus: >30 degrees
| varus: <5 degrees
113
what type of dysfunction can an increased elbow angle lead to?
dysfunction of the ulnar nerve (due to excessive friction)
114
how would the humeroradial and humeroulnar joints be described from a stability standpoint?
both are very stable joints; seldomly dislocates or subluxes
115
what are more common injuries at the humeroradial and humeroulnar joints, ligament tears or fractures?
fractures
116
what are the joint surfaces of the bones that make up the elbow joint, as far as concavity and convexity?
(1) humerus: convex
(2) radius: concave
(3) ulna: concave
117
***what are the open pack (resting position) and closed pack for the humeroradial joint?***
open pack: extension and forearm supination
| closed pack: 90 degrees of flexion, 5 degrees of supination
118
***what are the open pack (resting position) and closed pack for the humeroulnar joint?***
open pack: 70 degrees of flexion, 10 degrees of supination
| closed pack: full extension and supination
119
what direction are the roll and glide during elbow flexion? elbow extension?
flexion: roll and glide are both anterior
extension: roll and glide are both posterior
120
why aren't glides used clinically for mobilization of the humeroulnar joint?
the ulna will jam against the humerus, so a bony block typically prevents effective glides as manual therapy techniques
121
what manual therapy technique can be effective for improving flexion and extension at the elbow joint?
distraction
122
when the elbow extends, what accessory movement occurs?
the ulna abducts when the arm is extended
123
when the elbow flexes, what accessory movement occurs?
the ulna adducts when the arm is flexed
124
what prevents hyperextension at the elbow?
the olecranon entering the fossa blocks the motion to prevent hyperextension
125
what prevents excessive flexion at the elbow?
ulnar coronoid process enters it's fossa preventing excessive flexion (or large biceps muscle stops it early)
126
when the arm is fully extended, does the radius contact the humerus?
no
127
how does the contact between the trochlea and ulna differ between open chain and closed chain movements?
(1) open chain: no contact between the two bones between 30-120 degrees
(2) closed chain: constant contact
128
when does the radius come in contact with the humerus?
at end range elbow flexion
129
what are the two dynamic stabilizers of the humeroulnar joint?
(1) flexor carpi ulnaris
| (2) pronator teres
130
what does the humeroradial rely on for stability?
its ligaments and capsule; bone structure doesn't help as much at this joint as it does at the humeroulnar joint
131
where is the capsule of the elbow weakest? where is it strongest?
weakest: anterior and posterior (loose in these directions)
strongest: medial and lateral (reinforced by collateral ligaments)
132
how many bands make up the MCL? what are the names of the bands?
(1) anterior fibers
(2) posterior fibers
(3) transverse fibers
133
what ligaments make up the lateral collateral ligament complex?
(1) radial collateral ligament
(2) lateral ulnar collateral ligament (LUCL)
(3) annular ligament
134
what is the function of the anterior fibers of the MCL?
prevent valgus throughout flexion and extension
135
what is the function of the posterior fibers of the MCL?
prevent valgus in extreme (full) flexion of the elbow
136
what causes the terrible triad injury to occur at the elbow? what are the 3 structures that are damaged?
(1) extreme compression, hyperextension and valgus force
| (2) joint dislocation (extensive ligament damage), fracture of radial head, and fracture of coronoid process
137
what type of injury most commonly causes valgus stress?
falling with the arm extended
138
what are the functions of the LCL complex at the elbow?
(1) stabilizes against varus torque
(2) stabilizes against simultaneous varus and supination torque
(3) resists longitudinal distraction
(4) fixates radial head for rotation
(5) prevents posterior lateral instability
(6) prevents humeroulnar subluxation
139
when is the LUCL most taut?
at full elbow flexion
140
what is the function of the LUCL?
(1) prevents excessive varus and valgus through flexion and extension
(2) prevents excessive external rotation of proximal forearm relative to humerus
(3) prevents radial head from dislocating
141
what is the function of the annular ligament of the elbow?
prevents the radial head from distracting
142
what causes a posterolateral rotatory instability (PLRI) injury of the elbow?
varus, supination, and external rotation of the forearm, with the shoulder internally rotated
143
what is the function of the radial collateral ligament?
prevent excessive varus of the elbow
144
what are the functions of the MCL?
(1) limit extension at end range
(2) guide motion through flexion
(3) resist longitudinal distraction
145
how much elbow flexion and extension is required for most people to complete ADLs?
30 - 130 degrees of motion
30 degrees extension
130 degrees of flexion
146
what are the two most important ligaments of the elbow to provide stability?
(1) anterior fibers of MCL
| (2) LUCL
147
what type of loads are most damaging to the elbow?
bending and torsion
148
how many degrees of freedom are available at the radioulnar joint?
1 DOF; pronation and supination, radius rotates around a fixed ulna
149
how many degrees of motion occur at the radioulnar joint?
180 degrees; 90 from pronation / 90 from supination
150
what joint might contribute to the last 15-20 degrees of supination?
the radiocarpal joint
151
what are the closed pack and open pack positions of the proximal radioulnar joint?
(1) closed pack: 5 degrees of supination
| (2) open pack: 70 degrees flexion, 35 degrees supination
152
what are the closed pack and open pack positions of the distal radioulnar joint?
(1) closed pack: 5 degrees of supination
| (2) open pack: 10 degrees supination
153
***what are the 2 main functions of the interosseous membrane between the radius and ulna?***
(1) provide stability to both the proximal and distal radioulnar joints (prevents bones from spreading apart)
(2) helps transmit the load from the radius to the ulna and evenly distribute force to humerus
154
in a closed kinematic chain, how much of the load does the radius (radiocarpal joint) bear (like in a push-up)?
80%
155
what structure helps distribute force coming up the arm so that there is equal force on both sides of the humerus?
interosseous membrane
156
what are the three parts of the interosseous membrane?
(1) oblique cord
(2) central band
(3) distal oblique fibers
157
what structures help transmit open kinematic chain pulling forces at the elbow? (4)
(1) oblique cord
(2) annular ligament
(3) brachioradialis
(4) MCL (when strong external forces are carried)
158
what is the concave/convex rule at the proximal radioulnar joint in an OPEN CHAIN?
roll and glide are in OPPOSITE directions; ulna is fixed
| proximal ulna is concave, convex radius moves on ulna
159
what is the concave/convex rule at the distal radioulnar joint in an OPEN CHAIN?
roll and glide are in SAME directions; ulna is fixed
| distal ulna is convex, concave radius moves on ulna
160
what other motions occur when the elbow is flexed in an open chain?
(1) forearm supination
| (2) ER of the shoulder
161
what other motions occur when the elbow is extended in an open chain?
(1) forearm pronation
| (2) IR of the shoulder
162
in a closed chain (with elbow near full extension), what happens to the forearm when the shoulder is externally rotated?
the forearm pronates
163
in a closed chain (with elbow near full extension), what happens to the forearm when the shoulder is internally rotated?
the forearm supinates; helps lock the elbow in full extension for stability
164
what is the concave/convex rule at the proximal radioulnar joint in a CLOSED CHAIN?
roll and glide are in the SAME direction; radius is fixed
| proximal ulna is concave and moves on convex radius
165
what is the concave/convex rule at the distal radioulnar joint in a CLOSED CHAIN?
roll and glide are in the OPPOSITE direction; radius is fixed
(distal ulna is convex and moves on concave radius)
166
what structures provide passive stability to the proximal radioulnar joint? (4)
- 2 structures hold radial head
(1) annular ligament
(2) radial notch of ulna
- Also contribute to stability
(1) interosseous membrane
(2) quadrate ligament
167
what is the traffic light injury?
when parents pull their child up by their hands and the radial head subluxes from the annular ligament
168
***what is the most important structure and primary stabilizer of the distal radioulnar joint?***
TFCC (triangular fibrocartilage complex)
169
what can damage to the TFCC result in?
multi-directional joint instability
170
what structures provide stability to the distal radioulnar joint?
(1) TFCC
(2) interosseous membrane (controls pronation and supination)
(3) pronator quadratus
(4) extensor carpi radialis
171
what 2 ligaments help maintain the radius against the ulna during pronation and supination?
(1) dorsal radioulnar ligament
| (2) palmar radioulnar ligament
172
what are 2 common mechanisms of injury to the TFCC?
(1) fall on supinated, outstretched wrist
| 2) chronic repetitive rotational loading (ex. tennis players
173
how much pronation and supination is required for most people to complete ADLs?
50 degrees of pronation
| 50 degrees of supination
174
what joint is more mobile and less stable, the PRUJ or DRUJ?
DRUJ
175
what are the primary elbow flexors? (4)
(1) biceps brachii
(2) brachialis
(3) brachioradialis
(4) pronator teres
176
what muscles attach to the radius and have the ability to pronate/supinate? (3)
(1) biceps brachii
(2) brachioradialis
(3) pronator teres
177
when is the biceps brachii most active? least active?
most active with combined flexion and supination; least active with combined flexion and pronation
178
what is the strongest muscle of the elbow flexors, which is also known as the work horse of the flexors?
brachialis (largest cross section)
179
what is the weakest elbow flexor?
pronator teres (smallest cross section)
180
in what position is the shoulder in optimal position to shorten and produce force?
with the shoulder in extension with the elbow flexed
181
what head of the biceps has a larger internal moment arm for flexion? what does this mean?
the short head of the biceps has a greater internal moment arm; it can produce 15% greater flexion torque than the long head
182
what muscle of the elbow is the longest and has the largest moment arm? what is this muscle designed for?
brachioradialis; designed for speed
183
what muscle has the largest cross section of the flexors? what is this muscle designed for?
brachialis; power (heavy lifting)
184
which elbow flexor what a hybrid function of both speed and power?
biceps brachii
185
***at what range can the elbow flexors produce the most torque (strongest)?***
85-100 degrees of flexion
186
***at what range do the elbow flexors produce the least amount of torque (weakest)?***
near full extension (0 degrees)
| near full flexion (125+ degrees)
187
***what are the strongest muscles of the elbow? what are the weakest?***
Strongest to Weakest
| 1) flexors (strongest
(2) extension
(3) supination
(4) pronation (weakest)
188
how much stronger are the flexors than the extensors?
70%
189
why is flexor strength 20-25% stronger in supination than in pronation?
due to the role of the biceps when supinated
190
what are the primary extensors of the elbow? (2)
(1) anconeus
| (2) triceps
191
in minimum effort tasks, what initiates and controls elbow extension?
anconeus
192
***what is the order in which elbow extensors are activated?***
(1) anconeus (low effort)
(2) medial head of triceps (low effort)
(3) lateral head (moderate high effort)
(4) long head (high effort)
193
which elbow extensors works as a "reserve" and only kicks in during very high demand activities?
long head of triceps
194
what is the law of parsimony? how does this law benefit movement?
hierarchical activation of muscles based on required torque; helps with energy expenditure
195
what are 4 principles that the law of parsimony follows?
(1) smaller motor unit / smaller fibers before large ones
(2) red before white
(3) smaller cross section before larger
(4) uni-articular before bi-articular muscles
196
what is the long head of the triceps designed for?
speed and strength; long fibers, large volume
197
what are the lateral and medial heads of the triceps designed for?
together designed for strength; shorter fibers, medium cross section
198
what percentage of elbow torque is the anconeus responsible for?
15%
199
***at what range can the elbow extensors produce the most torque (strongest)?***
20-30 degrees of elbow flexion
200
when performing a pushing motion, the triceps and anterior deltoid act to do what?
the elbow extends as the anterior delt flexes, this causes an isometric co-activation which provide stability to the shoulder joint
201
if a person has the inability to use their triceps, how is that person able to supinate the forearm?
by internally rotating their shoulder
202
what are the primary supinators of the forearm? (2)
(1) supinator
| (2) biceps brachii
203
***which supinator muscle is most active?***
supinator (it's mono-articular); the biceps is recruited during higher power supination activities
204
at what angle does the biceps function best as a supinator?
near 90 degrees of elbow flexion
205
what synergistic action occurs with vigorous supination?
the triceps muscle activates to prevent elbow flexion (while the biceps is supinating)
206
what are the primary pronators of the forearm? what are the secondary pronators?
```
Primary
(1) pronator teres
(2) pronator quadratus
Secondary
(1) FCR
(2) palmaris longus
```
207
***what pronator is the most active?***
pronator quadratus (mono-articular)
208
***what pronator is only active during high power pronation activities?***
pronator teres (bi-articular)
209
what nerve runs through the two heads of the pronator teres and can become compressed?
median nerve
210
what muscle acts as a dynamic stabilizer of the distal radioulnar joint?
pronator quadratus
211
what muscle acts as a dynamic stabilizer of the proximal radioulnar joint?
pronator teres
212
what are the most common mechanisms of injury for MCL tears?
(1) trauma
(2) overuse (common in baseball players)
caused by valgus / ER rotational stress
213
what band of the MCL is most commonly injured?
anterior band
214
what are some complications that can arise from MCL tears?
(1) avascular necrosis of the capitulum
(2) displaced medial epicondyle
(3) damage to epiphyseal plate in children/teens
215
what is the name of the surgery to repair the MCL of the elbow?
Tommy John surgery
216
what is the most common elbow injury? what causes it?
lateral epicondylitis; repetitive wrist extension and supination
217
what extensor muscle is most commonly affected by lateral epicondylitis?
ECRB
218
how does a tennis elbow strap work?
(1) decreases stress applied to ECRB muscle
| (2) reduces muscle activation / contraction of extensors
219
MCL laxity can cause what type of injury?
capitulum compression injury
220
what is the 'most important' joint of the wrist? why?
radiocarpal joint; most motion of the wrist occurs at this joint (angular movements of the sagittal and frontal planes)
221
what carpal bones does the radius articulate with?
scaphoid and lunate
222
what does the TFCC do from a weight distribution standpoint?
helps transfer weight from radius to the wrist
223
when the wrist is compressed (think closed chain) what percentage of the compressive load is transferred by the radiocarpal joint? what percentage is transferred by the TFCC?
(1) radiocarpal joint: 80%
| (2) TFCC: 20%
224
of the compressive forces from the radius, what percentage of load is transferred to the scaphoid? what about the lunate?
(1) scaphoid: 60%
| (2) lunate: 40%
225
at the radiocarpal joint, how would you describe the articular surfaces of the radius, scaphoid, and lunate from concave/convex perspective?
(1) radius is concave in both frontal and sagittal planes
| (2) scaphoid and lunate are both convex in both frontal and sagittal planes
226
which direction do the first row of carpals glide when radial deviation occurs?
medially (towards the ulna)
227
how many DOF does the midcarpal joint have?
2; flexion/extension and radial/ulnar deviation
228
what bones make up the medial compartment of the midcarpal joint?
CONVEX capitate & hamate
which fit into
CONCAVE scaphoid, lunate and triquertrum
229
what bones make up the lateral compartment of the midcarpal joint?
CONVEX scaphoid
which fits into
CONCAVE trapezium / trapezoid
230
which compartment of the midcarpal joint has more motion?
medial compartment
231
what range (in degrees) of ulnar variance is considered normal?
15-25 degrees
232
what happens with positive ulnar variance? what pathology is this associated with?
(1) the ulna is longer than radius
| (2) TFCC injury
233
what happens with negative ulnar variance? what pathology is this associated with?
(1) the ulna is shorter than radius
| 2) Kienbock's disease (damage to lunate
234
what is the difference between intrinsic and extrinsic ligaments of the wrist?
(1) intrinsic: only join carpal bones
| (2) extrinsic: joint forearm with carpal bones or fingers
235
which ligaments are stronger, palmar ligaments or dorsal ligaments?
palmar ligaments (support weight of body, like in a push-up); the dorsal ones are thinner and weaker
236
what is the purpose of the V shape that the ligaments of the wrist create?
help passively guide radial and ulnar deviation
237
what is difference between the TFC and TFCC?
(1) TFC: only the ulnar disc
| (2) TFCC: the entire complex, including the disc or TFC
238
what is the axis for radial and ulnar deviation?
capitate
239
what structures make up the TFCC? (4)
(1) ulnar collateral ligament
(2) palmar ulnocarpal ligament
(3) palmar radioulnar joint ligament
(4) TFC (disc)
240
what movement occurs with wrist extension?
radial deviation
241
what movement occurs with wrist flexion?
ulnar deviation
242
when the wrist if fully flexed and moves into full extension, where does most of the motion occur throughout the motion?
(1) fully flexed to neutral; motion occurs between 1st and 2nd row of carpals
(2) from neutral to 30 deg extention; motion occurs between scaphoid and triquertrum / lunate
(3) from 30 deg extension to full extension; motion occurs between carpals and radius / TFCC
243
which direction does the first row of carpals glide during wrist flexion?
dorsally (posterior)
244
which direction does the first row of carpals glide during wrist extension?
palmarly (anterior)
245
which direction does the second row of carpals glide during wrist flexion?
dorsally (posterior)
246
which direction does the second row of carpals glide during wrist extension?
palmarly (anterior)
247
when the wrist is compressed which way does the first row of carpals glide? what structure can excessive wrist compression damage?
they glide medially (towards ulna); the TFCC
248
where do the primary and secondary muscles of the wrist attach?
(1) primary: muscles attach to carpal bones
| (2) secondary: cross carpal bones and attach to fingers and thumb
249
what are the primary (3) and secondary (4) wrist extensors?
```
primary
(1) ECRL
(2) ECRB
(3) ECU
secondary
(1) ED
(2) extensor indicis
(3) extensor digiti minimi
(4) EPL
```
250
muscles further from the axis have a better ability to do what?
produce torque
251
what is the main function of the wrist extensors?
position and stabilize the wrist during active flexion of the digits
252
what are the primary (3) and secondary (5) wrist flexors?
```
primary
(1) FCR
(2) FCU
(3) palmaris longus
secondary
(1) FDP
(2) FDS
(3) FPL
(4) APL
(5) extensor pollicis brevis
```
253
what muscle has the greatest wrist flexion torque potential?
flexor carpi ulnaris
254
how do the wrist flexors and extensors work synergistically during gripping or finger flexion motions?
with the wrist in neutral, the wrist flexors are on active insufficiency; gripping is most powerful with the wrist in 30 degrees of extension, so without the extensors, gripping wouldn't be as effective
255
when is gripping the strongest? the weakest?
(1) strongest in extension
(2) weakest in flexion
(neutral wrist strength falls between the two)
256
what are the primary ulnar deviators? (2)
(1) FCU
| (2) ECU
257
which ulnar deviator has a longer moment arm and is in the best position to produce torque?
ECU
258
what are the primary radial deviators? (3)
(1) FCR
(2) ECRB
(3) ECRL
259
what can be said about the radial deviators and their moment arms?
the ECRB and ECRL have a similar moment arm to the FCR
260
how much stronger are the flexors of the wrist when compared to the extensors?
70%
261
list the groups of muscles at the wrist from strongest to weakest
(1) flexors (strongest)
(2) radial deviators
(3) ulnar deviators
(4) extensors (weakest)
262
where does the proximal transverse arch of the hand go through? which bone is the keystone of this arch?
2nd carpal row; capitate
263
where does the distal transverse arch of the hand go through? which bone is the keystone of this arch?
MCPs; 2nd and 3rd MCPs
264
where does the longitudinal arch of the hand go through? which bone is the keystone of this arch?
2nd and 3rd rays; 2nd and 3rd MCP joint
265
what is the purpose of the arches?
told fold and hold objects in the hand
266
what can be said about the CMC joints of the hand in regards to available motion?
- 2nd/3rd CMC: plane joints; 1 DOF (almost no motion)
- 4th CMC: plane joint; 1 DOF (flex/ext can be observed)
- 1st CMC: saddle joint; 2 DOF
267
***which CMC joints have the most motion and allow for closing of the hand (opposition)?***
1st CMC
4th CMC
5th CMC
268
***which CMC joints have little to no motion?***
2nd CMC
| 3rd CMC
269
what ligaments provide stability to the CMC joints and prevent flexion and extension?
(1) dorsal / palmar carpometacarpal ligaments
| (2) intermetacarpal ligaments
270
in addition to the traditional movement of the MCP joints, how else can the joints be moved? (3)
(1) distracted / compressed
(2) A/P and lateral translations
(3) axially rotated
(joint mobs are commonly performed at this joint)
271
at the MCP joint, what movement accompanies flexion?
external rotation
272
at the MCP joint, what movement accompanies extension?
internal rotation
273
how many DOF do the MCP joints have? (NOT including thumb)
2; flex/ext and add/abd
274
how does the concave convex rule apply to the MCP joint? (NOT including thumb)
(1) during flexion / extension the roll and glide are the same direction
(1) during abduction / adduction roll and glide are the same direction
275
what position is the MCP joint most stable?
full flexion, or 90 degrees (closed pack position); lateral ligaments are taut and prevent lateral movement
276
what are palmar plates and what is their function?
(1) menicus-like structure made of fibrocartilage that help with joint congruence
(2) distribute stress on MCP surfaces which help prevent OA
277
***the collateral ligaments of the PIP and DIP joints are taut in what position?***
full extension
278
***the collateral ligaments of the MCP joints are taut in what position?***
full flexion
279
what are the closed and open pack positions for the PIP and DIP joints?
closed pack: full extension
| open pack: slight flexion
280
what additional motion occurs at the PIP and DIP joints with flexion? what about extension?
(1) flexion: external rotation
| (2) extension: internal rotation
281
***what can be said about the palmar plates (padding) between the IP joints compared to the MCP joint?***
less padding between IP joints than MCP joints; IP joints are more prone to OA
282
injuries at the IP joints are taped in what position? why?
full extension; prevent contractures and enhance joint stability during healing phase
283
what type of joint is the CMC of the thumb? how many DOF does it have?
saddle joint; 2 DOF (flex/ext and add/abd)
| *also known to have rotation which helps with opposition (technically has 3 DOF)
284
how does the concave / convex rule apply to the CMC of the thumb?
SAGITTAL PLANE
flexion / extension glide is SAME the roll
FRONTAL PLANE
abduction / adduction glide is the OPPOSITE as the roll
285
***what are the movements that create opposition at the CMC of the thumb?***
(1) abduction at the CMC joint
| (2) flexion with IR at the CMC joint
286
what 2 bones make up the articulation of the CMC joint?
(1) trapezium
| (2) metacarpal
287
what is closed pack position of the 1st CMC joint? what is open pack?
closed: extreme opposition
open: neutral
288
what ligament prevents separation between the 1st and 2nd CMC joints?
intermediate ligament
289
what are 2 common pathologies at the CMC joint?
(1) notorious for developing OA
| 2) sprain of UCL (ulnar/medial collateral ligament
290
how much flexion and extension does the MCP of the thumb have?
flexion: 30-60 degrees
extension: 0-15 degrees
291
what is the function of the MCP joint of the thumb?
provide further flexion during thumb opposition
292
what can be said about the capsule of the MCP of the thumb?
stronger than the MCP joints of the fingers; reinforced by sesamoid bones (palmarly)
293
what are the extrinsic flexors of the fingers? (3)
(1) FDS
(2) FDP
(3) flexor palmaris longus
294
***what is the main function of the FDS? can each tendon be controlled independently?***
(1) flex the PIP joints (except the 5th digit)
| (2) each PIP can be flexed independently
295
***what is the main function of the FDP? can each tendon be controlled independently?***
(1) flex the DIP joints
| (2) the FDP of the index finger can be independently controlled; the other 3 tendons are connected
296
what are the actions of the flexor pollicis longus? (3)
(1) flex CMC of thumb
(2) flex MCP of thumb
(3) flex IP of thumb
(4) flex and radially deviate the wrist
297
how many annular ligaments do each of the 4 fingers have? how many cruciate ligaments?
5 annular ligaments (pulleys) (A1-A5)
| 3 cruciate ligaments
298
how many annular ligaments does the thumb have? how many oblique ligaments?
2 annular ligaments (pulleys) (A1-A2)
| 1 oblique ligament
299
what do they pulleys do?
make muscle contraction more efficient
300
what are the extrinsic extensors of the fingers? (3)
(1) extensor digitorum
(2) extensor indicis
(3) extensor digiti minimi
301
what muscle extends the MCPs of the fingers
extensor digitorum
302
how does the extensor hood extend the PIP and DIP joints? (4)
(1) intrinsic muscles (lumbricals) contract
(2) this causes the PIP to extend
(3) which causes oblique retinacular ligament to stretch
(4) which extends the DIP
303
what are the actions of the extensor pollicis longus? (4)
(1) extend the CMC of thumb
(2) extend the MCP of thumb
(3) extend the IP of thumb
(4) adduct CMC when CMC is abducted
304
what are the actions of the extensor pollicis brevis? (2)
(1) extend the CMC of thumb
| (2) extend the MCP of thumb
305
what are the extrinsic muscles of the thumb? (4)
(1) EPL
(2) EPB
(3) APL
(4) FPL
306
how many intrinsic muscles does the hand have? what are the 4 sets?
20; divided into 4 sets
(1) thenar
(2) hypothenar
(3) adductor pollicis
(4) lumbricals and interossei
307
what is the purpose of the thenar muscles of the hand?
position the thumb to facilitate grasping
308
what is the purpose of the hypothenar muscles of the hand?
deepens transverse arch of the hand and enhances contact to hold objects
309
what is the function of the oblique and transverse heads of the adductor pollicis?
(1) BOTH heads flex and adduct the CMC
| (2) BOTH heads flex the MCP
310
which head of the adductor pollicis is stronger (can produce more torque)?
transverse head
311
what is the function of the lumbricals of the hand?
flex the MCP joints and extend the PIP and DIP joints (by pulling on lateral band extensor hood)
312
which MCP joints do the palmar interossei adduct?
2nd, 4th, 5th
313
why don't the dorsal interossei abduct the 5th digit?
it has it's own abductor (abductor digiti minimi)
314
which interossei are bipennate?
the dorsal interossei
315
in addition to abducting and adducting the fingers, what other function do they interossei assist with?
(1) MCP flexion
(2) PIP and DIP extension
(same action as the lumbricals)
316
which muscle is in a better position to produce a flexion torque at the MCP, the lumbricals or interossei?
the lumbricals
317
what do hand intrinsic and extrinsic muscles work synergistically to do?
open and close the digits of the hand (wrist extensors and finger flexors)
318
what are the steps involved with opening the hand? (3)
(1) early phase - ED extends the MCPs
(2) middle phase - lumbricals / interossei assist ED and extend PIP and DIP; also prevent MCP from hyperextending MCPs
(3) late phase - wrist flexors pull the wrist in slight flexion; this allows ED to fully extend fingers
319
what are the steps involved with closing the hand? (2)
(1) early phase - FDS, FDP, interossei flex PIP and DIP
| (2) late phase - wrist extensors slightly extend the wrist; finger flexion continues and ED decelerates flexion of MCPs
320
***what synergistic action is required for finger extension?***
wrist flexion
321
***what synergistic action is required for finger flexion?***
wrist extension
322
what is the extrinsic plus position? what is the intrinsic plus position?
extrinsic plus
(1) MCPs extended, PIP and DIP flexed
intrinsic plus
(1) MCPs flexed, PIP and DIP extended
323
what can happen when the intrinsic muscles of the hand don't work?
(1) can't control MCP flexion
| (2) can't extend PIP and DIP
324
what part of the body has a lot of motor control from the motor cortex of the brain?
the hand
325
what joint is most prone to instability and ligament tears in the hand?
midcarpal joint
326
is carpal instability static or dynamic?
it can be static, dynamic, or both
327
what are 3 common instabilities of the wrist?
(1) dorsal intercalated segment instability
(2) volar intercalated segment instability
(3) ulnar translocation of carpus
328
which row of carpals is more mobile?
the proximal row
329
where does zig-zag carpal instability occur?
midcarpal joint between distal and proximal carpal rows
330
what occurs during dorsal intercalated segment instability? what causes this?
capitate glides dorsally; tear of scapholunate ligament
331
volar intercalated segment instability? what causes this?
capitate glides volarly; tear of lunotriquetral ligament
332
what is Kienbock's disease?
avascular necrosis of the lunate
333
can spinal segments be moved individually?
no; movement of the spine involves several vertebral segments
334
where are the areas where load is transitioned in the spine? what are these areas prone to?
the curvatures; prone to dysfunction and pain
335
which curvatures are prone to dysfunction? (3)
(1) suboccipital
(2) CT junction
(3) LS junction
* TL junction isn't prone to injury
336
how does each main curvature of the spine develop?
(1) cervical lordosis: as an infant, trying to keep the head up while lying prone
(2) thoracic kyphosis: when child learns to sit up
(3) lumbar lordosis: when child starts to walk
337
what is the purpose of the curvatures of the spine?
absorb load, make the spine flexible, and dampen shock
338
how would you describe the height of the vertebral discs in the C/S, T/S and L/S?
(1) C/S - discs taller anterior than posterior
(2) T/S - disc height is even
(3) L1 - L3 taller posterior
L3 - L4 even
L4-S1 taller anteriorly
339
what can a flat cervical lordosis cause?
headaches
340
what can an increased thoracic kyphosis cause?
neck pain
341
what can an increased lumbar lordosis cause?
nerve root compression
342
where does the vertebral artery typically run?
C1-C6
343
***what motions are known to occlude the vertebral artery and block blood flow to the brain?***
extreme ranges of cervical extension and rotation
344
is the thoracic spine designed for mobility or stability?
stability; ribs provide stability but limit mobility (reduced rotation)
345
what type of joints are facet joints of the spine? do they follow the concave convex rule?
plane synovial joint; they don't follow concave convex rule
346
what segments of the spine have fat pads and a meniscus to help reduce compressive forces around the joints?
(1) cervical spine
| (2) lumbar spine
347
***what is the only segment of the spine to follow the concave/convex rule?***
occiput / C1
348
***what segment is responsible for the greatest amount of cervical rotation?***
C1/C2
| *50% of cervical rotation comes from this segment
349
what type of motion is favored with transverse, sagittal, and frontal facet orientations?
(1) transverse facets favor rotation
(2) sagittal facets favor flexion and extension
(3) frontal facets favor side bending
350
which segment allows for more side bending, the cervical spine or lumbar spine?
cervical spine
351
with the exception of C1/C2, what does each vertebral segment have?
(1) two synovial joints
| (2) one symphysis
352
what is the function of the nucleus pulposus?
works to absorb shock by dissipating and transferring loads across the vertebrae
353
what type of collagen is the annulus fibrosus primarily composed of?
type I collagen (structure is similar to ligaments)
354
what makes up majority of the nucleus pulposus? what type of collagen is more abundant in this structure
(1) proteoglycans (maintain positive pressure)
| (2) type II collagen
355
***how are the fibers of the annulus fibrosus oriented in the lumbar spine? what problems can this cause?***
(1) criss-crossed
(2) only 50% of the collagen fibers are tense during lumbar rotation while the other 50% are relaxed, which can cause damage to the disc with rotation
356
is the NP/AF higher in the cervical or lumbar spine? what are the implications of this?
(1) lumbar spine
| (2) because the L/S has a larger nucleus pulposus, it's more prone to disc herniation
357
where is the annulus fibrosus of the cervical spine strongest? weakest?
(1) strongest: anteriorly
| (2) weakest: posterior and laterally
358
what structure helps prevent posterio-lateral disc herniations of the cervical spine?
u-joints
359
what is the orientation of the annulus fibrosus of the cervical spine? (2)
(1) anterior: criss-cross (resists compression and tension)
| 2) posterior: longitudinal (resists flexion and tension
360
are herniations more common in the upper or lower cervical spine? why?
(1) lower
| (2) U-joints are less developed the further down the C/S you go
361
during flexion, what happens to the AF and NP at the lumbar spine?
(1) AF: compressed anteriorly and tensioned posteriorly
| (2) pushed posteriorly
362
during rotation, what happens to the AF at the lumbar spine?
internal shearing force
363
where are the vertebrae most vulnerable to fracture?
anterior portion of vertebral body (stress isn't applied here as often so bone is weaker)
364
***is disc pressure higher with sitting or standing?***
disc pressure is higher SITTING than it is during standing or walking
365
***is disc pressure higher with standing or lying down?***
standing
366
***what sitting position decreases disc pressure? what seated position increases disc pressure?***
(1) decreases: reclined
| (2) increases: slouched
367
***when lifting, what technique reduces pressure on the discs?***
bending the knees to lift an object
368
what movement causes greater torque (stress) on the upper cervical spine? lower cervical spine?
(1) lower cervical: during flexion (looking down)
| 2) upper cervical: during extension (looking up
369
what movements accompany protraction of the head? (2)
(1) upper C/S extends
| (2) lower C/S flexes
370
what movements accompany retraction of the head? (2)
(1) upper C/S flexes
| (2) lower C/S extends
371
why does poor sitting posture tend to cause added stress and pain?
it moves the line of gravity further from the center of gravity
372
how many DOF does the spine have?
3
373
what way do the facets glide with flexion of the lumbar spine?
superiorly and anteriorly
374
what happens to the intervertebral foramen and vertebral canal during lumbar flexion?
(1) intervertebral foramen: widen (vertically)
| 2) vertebral canal: widens (vertically and horizontally
375
what way do the facets glide with extension of the lumbar spine?
posteriorly and inferiorly
376
how does the superior vertebral body glide on the inferior vertebral body during lumbar extension?
posterior glide
377
what happens to the intervertebral foramen and vertebral canal during lumbar extension?
both canals narrow
378
what way do the facets glide with rotation of the lumbar spine?
(1) ipsilateral stretch of the facet capsule
| (2) contralateral compression of facet joint
379
what happens to the intervertebral foramen during lumbar rotation?
(1) ipsilateral foramen widens
| (2) contralateral foramen narrows
380
how does the superior vertebral body glide on the inferior vertebral body during lumbar rotation?
ipsilateral side glides posteriorly
381
what way do the facets glide with side flexion of the lumbar spine?
(1) ipsilateral inferior glide of the facet
| (2) contralateral superior glide of the facet
382
what happens to the intervertebral foramen during lumbar side flexion?
(1) ipsilateral foramen narrows
| (2) contralateral foramen widens
383
what is the roll and glide of the occiput on C1?
roll and glide are opposite
CONVEX facets of occiput
move on
CONCAVE facets of C1
384
what accessory movements occur at C1/C2 with flexion and extension?
(1) small anterior tilt with flexion
(2) small posterior tilt with extension
* no A/P or P/A glides at this joint
385
what way do the facets glide with flexion of the lower cervical spine?
superiorly and anteriorly
386
how does the superior vertebral body glide on the inferior vertebral body during flexion of the lower cervical spine?
anteriorly
387
what happens to the intervertebral foramen and vertebral canal during flexion of the lower cervical spine?
(1) intervertebral canal: widens
| (2) vertebral canal: narrows
388
in what population can extreme cervical flexion or extreme extension damage the spinal cord?
elderly and patients with arthritis of the spine; osteophytes develop in the vertebral canal
389
what way do the facets glide with extension of the lower cervical spine?
posteriorly and inferiorly
390
how does the superior vertebral body glide on the inferior vertebral body during extension of the lower cervical spine?
posteriorly and inferiorly
391
what happens to the intervertebral foramen and vertebral canal during extension of the lower cervical spine?
(1) intervertebral canal: narrows
| 2) vertebral canal: narrows (more than with flexion
392
what way do the facets glide with rotation of the lower cervical spine?
(1) ipsilateral facets glide inferiorly and posteriorly
(2) contralateral facets glide superiorly and anteriorly
*facets don't jam like in the lumbar spine
393
what happens to the intervertebral foramen and vertebral canal during rotation of the lower cervical spine?
(1) ipsilateral foramen narrows
(2) contralateral foramen widens
(3) vertebral canal isn't affected much with rotation
394
what percentage of cervical rotation comes from C1/C2? what about C2-C7?
(1) C1/C2 provides 50% of cervical rotation
| (2) C2-C7 provides 50% of cervical rotation
395
what way do the facets glide with side flexion of the lower cervical spine?
(1) ipsilateral facets glide inferiorly and posteriorly
| (2) contralateral facets glide superiorly and anteriorly
396
what happens to the intervertebral foramen during cervical side flexion?
(1) ipsilateral foramen narrows
| (2) contralateral foramen widens
397
do side bending and rotation of the LOWER cervical spine occur in the same or opposite directions?
same direction
398
do side bending and rotation of the lumbar spine occur in the same or opposite directions?
(1) same direction if facets are touching
| (2) opposite direction if facets are NOT touching
399
***do side bending and rotation of the UPPER cervical spine occur in the same or opposite directions? at what levels do these movements occur?***
opposite directions
(1) rotation occurs at C1/C2
(2) side flexion occurs at Occiput/C1
400
what direction do the condyles of the occiput glide with side flexion?
opposite direction of the roll; remember the concave / convex rule for occiput and C1
401
why is it important that the movements of the upper cervical spine are coupled?
to keep your eyes level with the horizon when you side bend or rotate your head
402
what way do the facets glide with rotation of the upper cervical spine?
(1) ipsilateral facet (of C1) glides posteriorly
| (2) contralateral facet (of C1) glides anteriorly
403
when you ROTATE your head RIGHT, what happens both osteokinematically and arthokinematically?
Rotation to the right occurs
Side flexion to the left occurs
(1) Occ/C1: right facet moves posterior, left facet moves anterior
(2) occipital condyles glide RIGHT (because side flexion is left)
404
when you SIDE BEND your head RIGHT, what happens both osteokinematically and arthokinematically?
Rotation to the left occurs
Side flexion to the right occurs
(1) Occ/C1: left facet moves posterior, right facet moves anterior
(2) occipital condyles glide LEFT (because side flexion is right)
405
what vertebrae have more flexion / extension, the thoracic or lumbar segments?
lumbar segments
406
what vertebrae have more rotation, the thoracic or lumbar segments?
thoracic segments
407
what segment of the C/S has the least amount of rotation?
Occiput/C1
408
what segment of the spine has the most side flexion?
cervical segments
409
where is the center of gravity located in the body? what can be said about this area?
(1) anterior to S2 within the sacroiliac ring
| (2) tends to be a very stable area with less motion
410
what is the keystone for motion between the upper and lower body?
the sacrum
411
what happens during sacral nutation?
(1) sacrum flexes
| (2) pelvis tilts posteriorly
412
what happens during sacral counternutation?
(1) sacrum extends
| (2) pelvis tilts anteriorly
413
what are the phases of the lumbosacral rhythm?
from full trunk flexion to full trunk extension
(1) initial phase: hip extensor muscles initial extension
(2) shared activation of hip and lumbar extensors extend the hip trunk further
(3) muscle activity ceases once LOG falls posterior to hips
414
when there is limited flexion of the hips (tight hamstrings), what compensation occurs?
increased flexion of the lumbar and lower thoracic spines
415
when lumbar spine mobility is limited, what compensation occurs?
increased flexion of the hip joint
416
what are the muscles of the back designed for?
to provide stability
417
what muscle action does the SCOM perform unilaterally (3) and bilaterally (1)?
```
unilateral
(1) ipsilateral side flexion
(2) contralateral rotation
(3) extension of the head
bilateral
(1) flexion of cervical spine
```
418
what muscle action do the scalenes (3) perform unilaterally and bilaterally (1)?
unilateral
(1) anterior: side flexion; contralateral rotation
(2) middle: stabilizer
(3) posterior: ipsilateral lateral flexor
bilateral
(1) flexion
419
what muscle action do the longus capitis & colli perform? (1)
(1) stabilize head and neck
420
what muscle action do the rectus capitis anterior and lateralis perform? (2)
(1) primary: stabilizer
| (2) secondary: flexion
421
which cervical extensors perform ipsilateral rotation? (2)
(1) Splenius capitis and cervicis
| (2) suboccipital muscles
422
which cervical extensors perform ipsilateral side flexion? (2)
(1) longissimus capitis and cervicis
| (2) traps
423
which cervical extensors perform contralateral rotation? (1)
(1) traps
424
which cervical extensors are in optimal alignment for extension? (1)
(1) semispinalis capitis and cervicis
425
where does the LOG fall for the AO joint? what does that mean from a muscle standpoint?
(1) anterior
| (2) produces a flexion moment, meaning the extensors have to fire
426
forward head posture increases the activity of what muscles?
extensors; to keep the head upright
427
how does forward head posture affect the lower segments of the spine?
(1) increased kyphosis of T/S
(2) anterior pelvic tilt
(can cause mid back and low back problems)
428
what muscle can act as both a hip flexor and hip extensor?
psoas major
429
what controls trunk flexion from upright to full flexion for the first half of the motion? the second half of the motion?
(1) first half: eccentric contraction of the extensors AND posterior ligaments and discs
(2) second half: posterior ligaments and discs
430
what are the main muscles that contract ipsilaterally (2) and contralaterally (3) during trunk rotation?
ipsilateral side
(1) internal oblique
(2) lats
contralateral side
(1) external oblique
(2) traps
(3) gluteus maximus
431
what are the muscles that contract during side flexion?
(1) contralateral QL
| (2) contralateral psoas major
432
what muscles initiate trunk flexion when doing a sit-up? what muscles kick in a little later?
(1) abdominals and obliques initiate flexion
| (2) hip flexors kick in later
433
when performing an oblique crunch, which muscles work synergistically unilaterally (2) and synergistically bilaterally (2)?
```
unilateral
(1) ipsilateral internal oblique
(2) contralateral external oblique
bilateral
(1) rectus abdominis
(2) transversus abdominis
```
434
which deep muscles of the spine provide motor and sensory feedback and are well developed in the cervical spine? (2)
(1) interspinalis
| (2) intertransvesarius
435
how does the position of an object affect muscle activity when lifting it off the ground?
if the object is further away, it increases the external moment and puts added stress on the muscles and passive structures of the spine
436
how can you reduce the compression of the spine during lifting activities? (4)
(1) reduce the load
(2) decrease external MA
(move object closer)
(3) increase internal MA (squat lower)
(4) lift in a slow controlled motion
437
why is a golfer's lift (single-leg RDL) recommended for picking up small, light objects?
extension of the leg reduces the flexion moment on the muscles and discs of the spine
438
generally speaking, where does most back pain stem from?
the joints and discs, not the muscles
439
***poor posture and chronic pain can lead to the deactivation of which muscles of the spine?***
typically deeper muscles will get weaker, and don't fire as much (multifidi, transverse abs, longus colli, etc.)
440
what structure of the lumbar spine is pulled on by the muscles to keep the vertical column erect?
thoracolumbar fascia
441
what are the main deep stabilizers of the lumbar spine? (2)
(1) multifidus
| (2) transverse abdominals
442
what are the main deep stabilizers of the cervical spine? (3)
(1) longus capitis
(2) longus colli
(3) multifidus
443
what are the main rotators of the trunk? (2)
internal and external obliques
444
what muscle attaches to and protects the facet capsules during motion
multifidus
445
what are the functions of the spinal ligaments? (4)
(1) limit motion
(2) maintain spinal curvatures
(3) stabilize the spine
(4) protect spinal cord, roots, and vessels
446
what is the function of ligamentum flavum? what is it composed of? where is it the thickest?
(1) function: decelerates lumbar flexion
(2) high percentage of elastin (recoils in extension)
(3) lumbar spine
447
what is the function of the supraspinous and interspinous ligaments?
limit forward flexion
448
what is the function of the intertransverse ligament? (2)
(1) limit forward flexion
| (2) limit contralateral side flexion
449
what is the function of the anterior longitudinal ligament? (3)
(1) prevents hyper extension
(2) maintains lordosis
(3) protects discs anteriorly
450
what is the function of the posterior longitudinal ligament? (2)
(1) limits flexion
| (2) reinforces posterior rise of intervertebral discs
451
what is the function of the facet capsules?
supports the facets and become taut in any position other than neutral
452
what are the main ligaments responsible for stability of the upper cervical spine?
(1) cruciform ligament
(2) alar ligament
(3) tectorial membrane
* cruciform ligament is most important
453
what is the most important ligament for keeping the odontoid process in check?
transverse ligament
454
what is one reason children have more mobility in their lumbar spine and are more prone to spondys than adults?
the iliolumbar ligament doesn't develop until your twenties and this ligament adds stability to the lumbosacral area
455
what is the function of the anterior sacroiliac ligament?
reinforce and add stability to the anterior side of the SI joint
456
what is the strongest ligament of the SI joint? what's it's function?
(1) interosseous ligament
| (2) binds the sacrum with the ilium
457
what is the function of the posterior sacroiliac ligament?
limits sacral translation
458
what is the function of the sacrotuberous ligament?
limits sacral nutation
459
how many capsules / ligaments are present in alls segments of the spine?
6
460
what ligament is important to maintain anterior stability of L4/L5 an L5/S1 segments?
iliolumbar ligament
