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Semester 4 FS Exam 2 > Elbow biomechanics > Flashcards

Elbow biomechanics Flashcards

(106 cards)

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1
Q

Bones of the elbow complex

A

Humerus
Ulna
Radius

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2
Q

Joints of the elbow complex

A

Elbow joints

Forearm joints

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3
Q

Distal humerus has what

A

Trochlea
Capitulum
Fossae
Epicondyles

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4
Q

Trochlea - description

A

Hour glass shape
Projects more distally on the medial side
Divided by tochlear groove

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5
Q

What does the trochlea articulate with

A

The trochlear notch of the ulna

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6
Q

Capitulum - description

A

Spherically shaped

Projects anterior-lateral

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7
Q

Capitulum articulates with

A

head of the radius

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8
Q

Fossae - description

A

Coronoid fossa
Radial fossa
Olecranon fossa

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9
Q

Which side are these located on:
Coronoid fossa
Radial fossa
Olecranon fossa

A

Coronoid fossa = ANT
Radial fossa = ANT
Olecranon fossa = POST

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10
Q

Epicondyles of the humerus are located where

A

Medial and Lateral

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11
Q

Proximal ulna has what

A 
Trochlear notch
Radial notch
Olecranon process
Coronoid process
Ulnar tuberosity
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12
Q

Trochlear notch - description

A

Semicircular concave surface
Divided by trochlear ridge
Nonarticulating surface

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13
Q

Radial notch - description

A

Faces laterally

Receives articulating circumference of the radial head

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14
Q

Where is the olecranon process

A

top of the trochlear notch

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15
Q

Where is the coronoid process

A

bottom of the trochlear notch

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16
Q

Ulnar tuberosity is located where

A

Under the coronoid process

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17
Q

What attaches at the ulnar tuberosity

A

brachialis

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18
Q

Proximal radius - what is located there

A

Articular fovea
Articular circumference
Radial tuberosity

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19
Q

Articular fovea - description

A

cup shaped concave surface

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20
Q

Articular circumference - description

A

convex rim articulates with the radial notch

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21
Q

Radial tuberosity - what attaches there

A

biceps

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22
Q

Elbow joints

A

Humeroulnar joint

Humeroradial joint

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23
Q

Humeroulnar Joint - articulation between what

A

Humerus and ulna

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24
Q

Humeroulnar joint - what type of joint

A

Hinge joint - Uniaxial diarthrodial joint

1 DF

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25
Arthrokinematics of humeroulnar joint - Flex/Ext
Sagittal plane | Frontal axis
26
Humeroulnar joint - slide/glide Open chain Closed chain
of concave ulna on convex trochlea of the humerus Open chain = same direction (ulna moves with respect to humerus) cave on vex Closed chain = opp direction (hum with respect to ulna) vex on cave
27
End ROM extension - humeroulnar
Bony - olecranon impact in fossa
28
End ROM flexion - humeroulnar
soft tissue approximation (biceps)
29
Close packed position of humeroulnar
full extension and supination
30
Humeroradial joint includes what
Radial head and capitulum ball and shallow socket
31
Humeroradial joint - arthrokinematics - flex/ext
Sagittal plane | Frontal axis
32
Humeroradial joint - slide/glide
of radial head on capitulum (concave on convex)
33
Humeroradial joint - extension
no contact between the articulating surfaces
34
Humeroradial joint - flexion
rim of the head reaches the radial fossa
35
Humeroradial joint - close packed position
90 degrees of flexion and about 5 degrees of supination
36
Osteokinematics of the elbow joint - Active ROM with respect to flexion
135-145 degrees (with forearm supinated) becomes smaller with pronation
37
Osteokinematics of the elbow joint - Passive ROM with respect to flexion
150-160 degrees (supinated again and is smaller with pronation)
38
Humeroulnar osteokinematics - trochlea to trochlear notch
``` Not a perfect fit Nonarticulating surface (middle) ```
39
Humeroulnar osteokinematics - orientation of the trochlear notch and ROM
Superior orientation will increase extension | Anterior orientation will increase flexion
40
Carrying angle - what leads to us having a carrying angle
Trochlea projection on the medial side is more distal resulting in a lateral deviation of the ulna with respect to the humerus
41
What is the typical carrying angle
10-15 degrees
42
Humeroradial joint - capitulum orientation is
Anterior
43
Humeroradial joint - contact is limited in
extension (there is a gap)
44
Humeroradial joint - contact increases with
flexion
45
Humeroradial joint - stress in the joint increases with
Extension - up until about 90 degrees and then goes away when separates
46
Humeroradial joint - stress in the joint decreases with
flexion
47
Stress in a joint -
The force in relationship to the contact area | Stress = force/area
48
Elbow complex - joint capsule
Loose Humeroulnar Humeroradial Proximal radioulnar
49
Elbow complex - stabilizing structures - Ligaments
Medial collateral Lateral collateral Annular
50
Medial Collateral ligament - portions
Ant post and trans portions
51
Medial collateral ligament - resists what
Valgus deviation and I/E Rot. | Resist an inc in the carrying angle
52
Lateral collateral ligament - Portions
``` radial collateral (ant) lateral ulnar collateral (post) Accessory LCL (runs into annular) ```
53
Lateral collateral ligament - resists
Varus deviation and I/E Rot
54
Annular ligament resists
Lateral and distal subluxation of the radius | Holds the head of the radius in the radial fossa
55
Elbow complex - MCL - anterior is tight in | posterior is tight in
Ant - taut in ext Post - taut in flex Transverse - small and does not attach to humerus
56
Elbow complex - annular ligament - sublux
Traction force on the forearm can cause distal subluxation of the proximal radioulnar joint
57
Elbow complex - annular ligament - how does the subluxation occut
Adult force pulls radius distally | Weight of the child force pulls ulna proximally
58
Forearm bones - proximal
Head of radius | Radial notch on ulna
59
Forearm bones - distal
Head of ulna | Ulnar notch on radius
60
Forearm joints -
Proximal (sup) radioulnar Distal (inf) radioulnar Middle radioulnar
61
Proximal (Sup) Radioulnar Joint includes what
Head of radius (convex) on radial notch of ulna (concave)
62
Arthrokinematics of the proximal radioulnar joint
Radius spins on capitulum and in radial notch
63
What encircles the radial head for stability - Proximal radioulnar joint
Annular ligament encircles the radial head for stability
64
What is the close packed position of the proximal (sup) radioulnar joint
Full extension and about 5 degrees of supination
65
Distal (inf) radioulnar joint - is made up of what
Head of ulna (convex) on the ulnar notch of the radius (concave)
66
Close packed position of the distal radioulnar joint
5 degrees of supination
67
Distal (inf) radioulnar joint - articular disc Shape Base Apex
Triangular shape Base at ulnar notch Apex at styloid process of ulna
68
Distal (inf) radioulnar joint - articular disc - what does it do
Binds the ulna and radius Proximal surface to ulna Distal surface to carpal bones
69
Arthrokinematics of the Distal (inf) radioulnar joint -
Ulnar notch spins on ulnar head and disc
70
Middle radioulnar joint
Interosseous margins | Interosseous membrane
71
Forearm ligaments
``` Anterior radioulnar ligament Posterior radioulnar ligament Interosseous membrane Quadrate ligament (ext of annular) Oblique cord Annular ligament ```
72
Radioulnar joint - what type
``` Diarthrodial uniaxial - pivot 1 DOF (supination and pronation) ```
73
Plane/Axis of Radioulnar joint - sup and pron
``` Longitudinal axis (head of radius to head of ulna) Transverse plane ```
74
Total ROM of the radioulnar joint
150 degrees (at 90 of elbow flexion)
75
Radioulnar joint - supination - radius and ulna
they are parallel to each other
76
Radioular joint - supination - limited by
tension of anterior radioulnar ligament and oblique cord
77
Radioulnar joint - pronation - radius and ulna
Radius crosses over ulna
78
Radioulnar joint - pronation - limited by
Radius/ulna bone to bone contact Post radioulnar ligament Post fibers of MCL Tension of biceps when elbow ext
79
Radioulnar relationship during sup/pron
Ulna remains in more or less same position Radius rotates about radioulnar joint axis Radius tips relative to its supinated position This opens gap at radial side of elbow joint The ulna undergoes slight abduction in pronation
80
Role of interosseous membrane in transmitting force | Interosseous membrane fiber orientation = ?
Force is transmitted through hand - radius - int mem - ulna - humerus Orientation = distal on ulna to prox on radius
81
Principal flexors of the elbow joint - and attachments
Biceps brachii - radial tuberosity Brachialis - ulnar tuberosity Brachioradialis - styloid of radius
82
Weak flexors of the elbow joint
Pronator teres | Long wrist and finger flexors
83
Primary extensors of the elbow joint - name mm and attachment
triceps brachii - olecranon process of ulna
84
Weak extensors of the elbow joint - name mm and attachment
Anconeus - lat epicondyle to post ulna
85
Main pronators of the radioulnar joint - name mm and locations
Pronator teres - proximal | Pronator quadratus - distal
86
Weak pronators of the radioulnar joint
Brachioradialis (from supinated position to mid way)
87
Main supinators of the radioulnar joint
``` Biceps brachii (prime) Supinator ```
88
Weak supinators of the radioulnar joint
Brachioradialis (from pronated position to mid way)
89
Biceps contribution to elbow joint stability - with elbow extended - biceps contraction
Compresses the elbow joint
90
Biceps contribution to elbow joint stability - with elbow flexed - biceps contraction
distracts the elbow joint
91
Biceps effectiveness as a supinator
changes with elbow flexion angle | most effect at 90 flex
92
The greater the net muscle force required, the greater the
bone on bone joint force
93
Which epicondyle is more pronounced
Medial
94
Post view of the humerus - what is not visible
capitulum | It is anteriorly oriented on the lateral aspect
95
Radial notch is located where
on the proximal ulna - lat side
96
Ulnar notch is located where
on the distal radius
97
Radial tuberosity is oriented which way | Implication
medially | biceps is a supinator
98
Ulnar tuberosity is located where
under the coronoid process | is an ant structure
99
Joint force is usually coming from what
muscle force rather than from the external load
100
What is required to balance external load torque
net muscle balance force
101
Changes in moment arm with elbow joint angle | Optimal angle for peak ma
between 102 and 108 = largest ma BUT doesnt mean they are producing max force here When look at length - they are actually all at a smaller length
102
axis of the elbow joint is where
between the epicondyles
103
When look at ma and length where is the optimal flexion angle to produce max torque
75-85 degrees of flexion
104
Elbow forces and torques with crutch walking - optimal degree of flexion
About 20-25
105
Elbow forces and torques with crutch walking - why is having too much flexion bad?
Even though triceps are at good length and ma, the ma from the load has been multiplied so the crutches have to work harder
106
Elbow forces and torques with crutch walking - why is having too much extension bad?
Because then the triceps are too long and we want them to actually work Also force coming through wrist (radius)

Semester 4 FS Exam 2 (1 decks)

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