Elbow And Forearm Flashcards
0
Q
Articulations at the humeroulnar joint
A
Humerus–> trochlea
Ulna–> trochlea fossa
1
Q
What are the articulations of the elbow
A
Humeroulnar
Humeroradial
2
Q
What are the articulations at the humeroradial joint
A
Humerus–> capitulum
Radius–> head
3
Q
What is the function of the elbow and forearm
A
Add mobility of the hand in space by:
Shortening and or lengthening the arm
Rotating the forearm
Combination of both
Provide control and stability
Skilled hand motions
Forceful upper extremity motions
4
Q
What are the articulations at the forearm
A
Proximal or superior radioulnar
Distal or inferior radioulnar
5
Q
_____ is made up of two joints that function together
A
Elbow
6
Q
What kind of joint is the elbow and why
A
Modified hinge. There is a few degrees of axial rotation at the extremes of flexion and extension.
7
Q
The _____ is more distal then the _____ in terms of elbow arthrology
A
Trochlea
Capitulum
8
Q
What is the axis of the elbow joint
A
Transverse (medial-lateral) for flexion/extension
9
Q
What is the carrying angle formed by
A
Longitudinal axis of the humerus
Longitudinal axis of the forearm
10
Q
_____ is lateral deviation of a distal segment with respect to a proximal segment
A
Valgus
11
Q
What is the normal cubital valgus for males and females
A
Females–20-25 degrees
Males: 10-15 degrees
12
Q
______ medial deviation of a limb segment with respect to the proximal segment
A
Varus
13
Q
The joint capsule of the elbow encloses what?
A
Humeroulnar joint
Humeroradial joint
Proximal radioulnar joint
14
Q
The elbow is reinforced by what structures
A
Collateral ligaments
15
Q
What would you see if you had a strained ligament at the elbow
A
Extremes in valgus
16
Q
_____ stabilizes the medial elbow joint and prevents forearm abduction
A
Medial collateral ligament
17
Q
Where does the anterior band of the mcl attach
A
Medial epicondyle
Side of the coronoid process
18
Q
______ reinforces the humerulnar joint against valgus/abduction stress
A
Anterior band of mcl
19
Q
_____ Attaches to the epicondyle and the olecranon
A
Posterior band of the mcl
20
Q
When is the posterior band of the mcl taut
A
With valgus and extremes of elbow flexion
21
Q
______ attaches to the olecranon and the coronoid process
A
Transverse or oblique band of the mcl
22
Q
______ stabilizes the lateral elbow joint and prevents forearm adduction (varus stress)
A
Lateral collateral ligament
23
Q
______ goes from the lateral epicondyle and blends with the annular ligament and some forearm muscles. It protects the lateral joint and stabilizes against varus stresses.
A
Lcl
24
What are the components of the lcl
Radial--blends with the annular ligament
| Ulnar--lateral
25
Flexion of the humeroulnar joint is limited by what
Soft tissue
26
Ranges for humeroulnar joint flexion
135-150
27
What are the values of humeroulnar joint extension
0-5 degrees of hyperextension
28
Humeroulnar king extension is a ______ position
Closed packed position
29
Most ADL's are done in ______-______ humeroulnar joint extension or flexion
30-130
30
In _____ the rim of the radius slides in the capitular-trochlear groove
Humeroradial joint flexion
31
In full ____ the radius reaches the radial fossa of the humerus
Humeroradial joint flexion
32
Describe extension at the humeroradial joint
There is NO contact between the capitulum and the radial head
33
What is the axis at the humeroulnar joint
The medial-lateral axis is through the center of the trochlea
34
What are the arthrokinematics of the humeroulnar joint in extension
Inferior sliding, some rolling at extremes of flexion and extension
35
What are the arthrokinematics of the humeroulnar joint in flexion
Concave trochlea (ulna) rolls and slides superiorly on the coves trochlea (humerus)
36
Where is the medial lateral axis of the humeroradial joint
Center of the capitulum
37
What are the arthrokinematics of the humeroradial joint in extension
There is no contact between the capitulum and the radial head
38
What are the arthrokinematics of the humeroradial joint in flexion
Active--muscle contraction pulls the radial fovea to the capitulum
The fovea of the radius rolls and slide superiorly on the capitulum
39
What are the fibers oriented like in the interosseous membrane
Oblique medial and distal--away from the radius
40
What is the function of the interosseous membrane
Bind radius to ulna
Attachment for some extrinsic hand muscles
Force transmission through the upper limb
41
_____ is for resisting traction or distraction
Oblique cord and annular ligament
42
In upper extremity weight bearing ____ of the compression force is transferred through the radius
80%
43
How does the force transmission of the interosseous membrane work
Compression force on radius stretches the interosseous membrane. The fiber orientation of it transfers some force to the ulna and limits the force of the humeroradial joint.
44
The interosseous membrane transfers components of ______ from the radius and the ulna because major elbow flexors, pronators and supinator a have distal attachment to the radius
Muscle force
45
IM does not resist force in the _____ direction
Distal
46
Why does the IM have no resistance to distraction
The distal pull on the radius slackens the IM. The oblique cord and annular ligament accept the load and brachioradialis contracts.
47
Pronation and supination are ______ movements
Open kinematic chain
48
What bone rotates in supination and pronation
Radius
49
What happens at the proximal an distal radioulnar joints with pronation and supination
Proximal: radial head rotation
Distal: rotational displacement
50
What is the function of the proximal and distal radioulnar joints
Independent rotation of the hand
51
______ binds the radial head to the radial notch on the ulna and encircles the head and neck of the radius
Annular ligament
52
_____ is lined with articular cartilage and synovial to decrease friction during radial head rotation
Annular ligament
53
What are the ligaments of the proximal radioulnar joint
Annular and quad rate
54
_____ connects to the border of the radial notch to the neck of the radius
Quadrate ligaments
55
_____ reinforces inferior joint capsule and helps keep the apposition between radial head and radial notch
Quadrate ligament
56
______ limits the spin of radial head with pronation and supination
Quadrate ligament
57
What injury normally happens in the proximal radioulnar joint
Dislocation, called pulled elbow syndrome
58
What is pulled elbow syndrome
2-4 years is the average age. It's a pull on the extended primates arm causing a tensile force at the elbow. The radial head is pulled from the annular ligament. As children get older the annular ligament gets thicker and resists tearing, making this injury less likely.
59
What kind of joints are the radioulnar joints
They are unisxial pivot joints
60
What is the axis for the radioulnar joints for pronation and supination
A longitudinal axis passes through the head of the radius and the center of the distal ulna.
61
What are normal ranges for pronation and supination
Zero reference position--thumb up-- midway between pronation and supination.
Pronation: 75-90
Supination: 85-90
62
When the elbow is in extension what is pronation limited by
The passive tension on the biceps
63
When the elbow is in extension what is supination limited by
Passive tension on the interosseous membrane
64
Functional activities are in the ranges of _____ in regards to pronation and supination
50-50 pronation/supination
65
Arthrokinematics of supination for the distal radioulnar joint
Concave ulnar notch of the radius rolls and slides in the same direction as the radial head. The loser end of the radius rotates around the head of the ulna
66
Arthrokinematics of supination for the proximal radioulnar joint
The radial head rotates within the annular ligament and the radial notch. Fovea is slightly concave and articulates with the capitulum of the humerus.
67
Arthrokinematics of pronation for the distal radioulnar joint
Concave ulnar notch of the radius rolls and slides in the same direction as the radial head
68
Arthrokinematics of pronation for the proximal radioulnar joint
The convex radius rotates with in the annular ligament on the concave radial notch of the ulna.
69
Arthrokinematics of the humeroradial joint for active pronation
The fovea of the radial head spins against the rounded capitulum of the humerus.
Pronator teres contraction causes the radius to migrate proximally and compress the capitulum.
This is the screw home mechanism of the elbow.
70
Osteokinematics of closed kinetic chain for pronation
External rotation of the humerus and ulna
71
Osteokinematics of closed kinetic chain for supination
Internal rotation of the humerus and ulna
72
Arthrokinematics for pronation supination closed kinetic chain for proximal radio ulnar joint
Annular ligament and radial notch (ulna) rotate around a fixed radial head.
73
Arthrokinematics for pronation supination closed kinetic chain for distal radio ulnar joint
Convex ulnar head rolls and slides in opposite directions on the concave ulnar notch of the radius.
74
What is the muscle function of the distal attachment--ulna
Flex or extend
| Cannot primate or supinate
75
What is the muscle function of the distal attachment--radius
Flex or extend, pronate or supinate
76
Elbow flexors muscle action line is _____ to the joint axis
Anterior
77
What are the elbow flexors
Biceps
Brachialis
Brachioradialis
Secondary flexor is pronator teres
78
What are the actions of biceps brachii
Simultaneous elbow flexion and forearm supination
Shoulder flexion
GH joint stabilization
79
______ weakness would be decreased strength in elbow flexion and forearm supination and decreased GH stability with orator cuff pathology
Biceps brachii
80
_______ tightness would be decreased range of motion in elbow extension and forearm pronation
Biceps brachii
81
Action of Brachialis
Primary elbow flexor
82
Is the Brachialis affected by radial head rotation
No
83
What elbow flexor has the largest pcsa
Brachialis
84
Where does the Brachialis have its greatest torque
100 degrees
85
_____ weakness would lead to decreased elbow flexion in all positions
Brachialis
86
_____ tightness would lead to decreased elbow extension in all positions
Brachialis
87
What is the action of brachioradialis
Elbow flexion with forearm rotation to neutral (midway between pronation and supination)
88
What is an example of an eccentric action with the brachioradialis
Hammering
89
_____ weakness is decreased elbow flexion with neutral forearm
Brachioradialis
90
______ tightness would cause decreased elbow extension with a neutral forearm
Brachioradialis
91
What is a spurt muscle. What are examples
Moves quickly through a large range of motion
Biceps and Brachialis
92
Characteristics of a spurt muscle
Proximal attachment is for from the joint axis
Distal attachment is close to the joint axis
There is a large rotatory component
Small compression component
93
What is a shunt muscle and what are examples
They are for joint stability and the brachioradialis is an example.
94
Characteristics of a shunt muscle
Proximal attachment is close to the joint axis
Distal attachment is far from the joint axis
Large compression component
Small rotatory component
95
_____ is the perpendicular distance from the point of rotation (joint axis) to the line of pull (muscle action line)
Muscle moment arm (MA)
96
What are the MA longest to shortest for the elbow flexors
Brachioradialis
Biceps
Brachialis
Pronator teres
97
Elbow flexion torque is ______ than extension torque
70% greater
98
Elbow flexion torque is 20-25% greater in _____ than _____
Supination
Pronation
Because biceps comes in and is stronger than brachioradialis
99
Where is the Highest amount of elbow flexion torque
@ 90 degrees. This is the optimal length tension relationship and internal MA
100
Explain elbow flexion and shoulder extension
Biceps generate a slow flexion torque
Posterior deltoid does GH extension. It is a synergist and enhances the biceps force.
101
explain pulling
There is an elongation at the GH, shortening at the elbow which gives a slower contraction velocity but a greater torque generated
102
For the elbow extensors the muscle action line is passing _____ to the joint axis
Posterior
103
What are the elbow flexors
Tricpeps
| Anconeous
104
Action of triceps brachii
Primary elbow extender
| Medial head is active through all rom
105
Which head of the triceps has the largest pcsa
Lateral
106
What would happen if someone had weak triceps
Almost complete loss of elbow extension strength
107
What would be seen if someone had tight triceps
Limitations in elbow flexion and shoulder elevation rom
Also could see functional impairments like feeding and hygiene
108
What are the actions of the anconeous
Contributes to extension
| Anterolateral stability
109
_____ pulls the capsule away and prevents anterior impingement during flexion
Anconeous
110
________ weakness may lead to impingement of the posterior capsule and decreased ability to pronate the forearm with a fixed hand
Anconeous
111
Where is the most torque produced for elbow extension
At 90
112
Where is the longest internal moment arm for elbow extension
Near full extension
113
For Elbow extension _____ not ______ determines torque
Muscle length
Leverage
114
_____ provide static stability to the elbow
Elbow extension
115
______ stabilize a flexed elbow
Elbow extensors
116
Explain elbow extension with shoulder flexion
Anterior deltoid flexes the GH--synergistically to the triceps
117
What movements do we use elbow extension and shoulder flexion
Pushing a door and throwing a ball
118
What are the supinators
Primary mover are the supinator and biceps
Secondary mover is radial wrist extensors, extensor pollicis longus, extensor indicis, brachioradialis
119
What are the prime movers for pronators
Pronator quadratus is the prime mover and so is the pronator teres and this is also a secondary flexor.
120
______ is the most active consistently used pronator regardless of elbow position
Pronator quadratus
121
_____ is the stabilizer of the distal radioulnar joint
Pronator quadratus
122
_____ is at its greatest with high power like pitching and overhead light bulb
Pronator teres
