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Elbow Complex Flashcards

1
Q

What anatomy makes up the humeroulnar joint?

A

Humerus
Trochlea
Trochlea Groove
Coronoid fossa
Olecranon fossa
Capitulum
Ulna
Olecranon Process → has a bursa
Coronoid Process
Trochlear notch

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2
Q

what anatomy makes up the humeroradial joint?

A

Humerus
Capitulum
Radial fossa
Radius
Radial head

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3
Q

what anatomy makes up proximal radioulnar joint?

A

Radius
Radial head
Ulna
Radial notch

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4
Q

what anatomy makes up the distal radioulnar joint?

A

Radius
Ulnar notch
Ulna
Head of ulna
Articular Disc (TFC)

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5
Q

what kind of joints are the humeroulnar & humeroradial?

A

hinge joint
uniaxial diarthrodial w/ 1 DF (flex/ext)

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6
Q

what kind of joints are the superior & inferior radioulnar?

A

Pivot joint (trochlear joint), uniaxial diarthrodial with 1 DF (pronation/supination)

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7
Q

what is the problem with the joint capsule?

A

Bathed in common synovial fluid
Potential for cross contamination of pathology → can bathe all 3 joints at once spreading infection easily

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8
Q

Describe the Joint Capsule

A

Fairly large, loose, & weak anteriorly & posteriorly
Sides reinforced by ligaments
Encloses all 3 proximal joints

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9
Q

What are the 4 ligaments of the elbow?

A

Medial Collateral
Lateral Collateral
Annular Ligament
Interosseous Membrane

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10
Q

What does the anterior head of the medial collateral ligament do?

A

Valgus stress stabilizer
Protects best 20-120 degrees flexion

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11
Q

what does the posterior head of the medial collateral ligament do?

A

Less significant than anterior in valgus stability
Co 1 DF valgus restraint at 120 degrees
2 DF at 30 & 90 degrees

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12
Q

what does the oblique head of the medial collateral ligament do?

A

Helps maintain joint surface
Like tape that holds down anterior & posterior fibers

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13
Q

what does the lateral collateral ligament do?

A

Resists varus stress
Resists distractive (tension) forces of joint surfaces
Weaker than medial collateral ligament

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14
Q

what does the annular ligament do?

A

Stabilizes head of radius to ulna
Very strong

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15
Q

why does the annular ligament have reduced congruency?

A

the annular ligament is circular and the radius is a football shape

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16
Q

what are the osteokinematic & arthrokinematics of the humeroulnar joint?

A

Osteokinematics: Flexion & Extension
Arthrokinematics: concave on convex (open chain)
Convex on concave (closed chain)
Flexion: anterior roll, anterior glide
Extension: posterior roll, posterior glide

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17
Q

what are the osteokinematic & arthrokinematics of the humeroradial joint?

A

Osteokinematic: Flexion & Extension
Arthrokinematic: concave on convex
Flexion: anterior roll, anterior slide
Extension: posterior roll, posterior slide

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18
Q

what are the osteokinematics & arthrokinematics of the proximal radioulnar joint?

A

osteokinematics : pronation & supination
Radial head is longer A-P supinated
Radial head is longer M-L pronated
Radial head spins on capitulum in relation to radial groove on ulna

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19
Q

what are the osteokinematics & arthrokinematics of the distal radioulnar joint?

A

Osteokinematics: pronation & supination
Concave radius on convex ulna
Pronation: anterior (palmar) roll & glide
Supination: posterior (dorsal) roll & glide

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20
Q

what is a carrying angle?

A

Axis of the elbow ROM makes the carrying angle
Measured long axis of humerus & forearm (ulna b/c fixed)
Disappears with pronation & supination combined with full elbow extension as well as full elbow flexion

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21
Q

what are the normal degree for carrying angle?

A

5 degrees men
15 degrees women

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22
Q

what is the open pack position?

A

Termed resting position
Position which the joint capsule & ligaments have the greatest laxity
Greatest amount of accessory mobility present

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23
Q

what is the closed pack position?

A

Position in which the joint capsule & ligaments are the most taut
Most often it is a position of greatest joint congruency as well but not always

24
Q

what are some check reins to extension?

A

olecranon/olecranon fossa (not a good one b/c bone on bone)
Anterior capsule & anterior portion of collateral ligament tension
Flexor muscle tension

25
when is the humeroulnar joint in closed pack & humeroradial joint in open pack?
at terminal extension
26
when is the humeroradial joint in closed pack position?
90 degrees flexion
27
what are flexion check reins?
Approximation of anterior musculature Supination → greater flexion range b/c levers of forearm parallel Pronation → radius over ulnar, increase bony surfaces Bony articulation Passive stretch of triceps & posterior capsule
28
what are the primary movers into flexion?
Biceps brachii, Brachioradialis, Brachialis
29
what are the secondary movers into flexion?
Pronator Teres, wrist flexors (b/c they cross elbow joint)
30
what determines the role of flexor muscles?
Location of muscles Joint ROM Forearm position Magnitude of load applied Type of muscular contraction Velocity of movement
31
what is active insufficiency?
Agonist muscle is too short or too long to produce “effective” & “efficient” tension so no further ROM can be achieved actively Actin & myosin are either too far apart or too close together
32
what is passive insufficiency?
Antagonist muscle is on stretch & is too short (too elongated) to allow further passive ROM
33
is the biceps brachii a spurt or shunt muscle?
Spurt Muscle = Mobility Muscle → really creates movement Increased rotary component, increased angle of pull Insertion close to axis of elbow joint
34
when is the MA best for the biceps brachii?
MA greatest between 80 & 100 flexion
35
why is the biceps not very effective in terminal extension?
Not good b/c small angle of pull, small MA & rotatory component
36
when is the biceps brachii most active?
Most active w/ forearm supinated & for power activities, both concentric & eccentric → line of pull is best, fiber orientation is best here
37
is brachioradialis a shunt or spurt muscle?
Shunt Muscle = Stabilizing Muscle Decreased rotatory component, decreased angle of pull (lays flat) Increased compressive force → pulls distal closer to proximal (provides good pivot point) Insertion far from joint axis
38
when is MA greatest for brachioradialis?
MA greates between 100 & 110 degrees flexion → picks up where biceps leaves off
39
when is the brachioradialis most effective?
Most effective with forearm 1) Neutral Position (palm facing side/thumb points forward) 2) Full Pronation (b/c fiber orientation muscle laying on top, closer to optional position)
40
is brachialis a spurt or shunt muscle?
Spurt Muscle Insertion close to axis of elbow joint at ulna Forearm position Brachialis most efficient → all of them
41
when is the MA best for brachialis?
MA greatest at approximately 100° flexion Increased rotatory component, improved length/tension relationship
42
why is the brachialis considered the work horse muscle?
Effective in all forearm positions, all contraction types, all speed Can be isolated in pronated b/c biceps in worst & brachioradialis in 2nd worst potion
43
which head of the triceps is considered the work horse?
Medial head is work horse → always active and resisted elbow extension
44
why are we able to screw a screwdriver without our arm flexing?
Triceps acts synergistically with biceps during resistive forearm supination
45
describe the Anconeous muscle?
Lateral epicondyle to olecranon process Initiated elbow extension Has attachment to posterior capsule (will eccentrically contract to keep from getting pinched) & annular ligament Active with forced finger flexion & extension
46
what are the normal degrees of pronation, supination & neutral?
85° pronation: palm facing posterior (inferior) 90° supination: palm facing anterior (superior) Neutral position: palm faces medially w/ thumb pointed anterior (superior)
47
what are the check reins to pronation?
radius over ulna, posterior fibers of medial collateral ligament, posterior radioulnar ligament, supinator muscle
48
what are the check reins to supination?
anterior radioulnar ligament, oblique cord, pronator teres, pronator quadratus, interosseous membrane, annular ligament
49
what is the open pack position for proximal radioulnar joint?
Open pack positon 35° supination, 70° elbow flexion Good position to joint play
50
what is the closed pack position for the proximal radioulnar joint?
Closed pack positon 5° supination, elbow extended Good position for promoting stability
51
what is the open & closed pack of distal radioulnar joint?
Open pack 10° supination Closed pack 5° supination
52
what two muscles create supination?
Biceps Brachii Active when resistance is met & with increased speed Supinator Acts by unwinding: pulls shaft & distal end of radius off the ulna
53
how does the synergistic relationship work for supination?
- Supinator & Biceps Brachii work synergistically w/ forceful supination at 90° elbow flexion - Anconeous & to lesser extend the triceps contracts isometrically to stabilize the ulna - Synergist of flexor & extensor to produce supination
54
what muscles create pronation?
Pronator Quadratus Active with & w/o resistance and fast and slow speeds Pronator Teres → Secondary elbow flexor
55
what is lateral epicondylitis?
Repetitive use, contractions primarily of extensor carpi radialis brevis Tensile stress leading to microtears leading to inflammatory cascade
56
what is medial epicondylitis?
Repetitive use primarily of pronator teres, flexor carpi radialis, & sometimes flexor carpi ulnaris
57
what is nursemaid's elbow?
Longitudinal traction (tensile) force Radial head extraction from annular ligament

Biomechanics & Kinematics (10 decks)

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