Elbow Complex Flashcards

1
Q

Elbow Complex consists of:

A

-Elbow Joint; Humeroulnar + Humeroradial Joints
-Proximal radioulnar joint (PRUJ)
-Distal radioulnar joint (DRUJ)

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2
Q

Elbow Functions

A

-Mobility for the hand by shortening or lengthening entire UE
-Stability for forceful movements (Ex: tools)
-Links shoulder to hand

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3
Q

Elbow Joint
(HUJ, HRJ)

A

Compound, modified/loose Hinge Joint
1 DOF; Flexion and Extension
Small amounts of axial rotation ABD/ADD of ulna

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4
Q

Proximal/ Distal Radioulnar Joints
(DRUJ) (PRUJ)

A

Linked; Function as 1 joint
Uniaxial, diarthrodial Pivot joint
1 DOF; Rotation of forearm (Pronation/Supination)

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5
Q

Humeroulnar (HUJ) Articulation

A

Trochlea of humerus with Trochlea notch of ulna

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6
Q

HUJ Open-Packed Position

A

70 deg supination; 10 deg flexion

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7
Q

HUJ Close-Packed Position

A

Full extension and supination

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8
Q

During elbow flexion at the HUJ, there is an ________ roll and _______ glide.

A

anterior; anterior

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9
Q

During elbow extension at the HUJ, there is a _______ roll and ________glide.

A

posterior; posterior

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10
Q

Humeroradial (HRJ) Articulation

A

Capitulum with Radial Head

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11
Q

HRJ Open-Packed Position

A

Full extension and supination

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12
Q

HRJ Close-Packed Position

A

90 deg flexion; 5 deg supination

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13
Q

During elbow flexion at the HRJ, there is a ______roll and a ______glide.

A

Anterior; anterior

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14
Q

During elbow extension at the HRJ, there is a _______ roll and ________glide.

A

Posterior; posterior

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15
Q

HUJ and HRJ Structures

A

-Joint capsule
-Medial and Lateral Collateral Ligaments

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16
Q

HUJ and HRJ Joint Capsule

A

-Fairly large, loose, weak anteriorly/posteriorly
-Synovial folds expand for full ROM
Synovial Membrane
-Lines olecranon, coronoid, radial fossae
-Lines medial trochlea and lower part of annular ligament
-Folds in to divide the HUJ and HRJ
Fat Pads
-Between capsule and synovial membrane
-By the olecranon, coronoid, radial fossae

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17
Q

HUJ and HRJ Medial (Ulnar) Collateral Ligament

A

Anterior bundle
-Primary restraint to valgus at 20-120 deg elbow flexion
Posterior bundle (vertically oriented)
-Limits elbow extension; guides motion throughout flexion
Transverse fibers
-Limits longitudinal distractions

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18
Q

HUJ and HRJ Lateral Collateral Ligament Complex

A

Lateral (radial) Collateral Ligament
Lateral (ulnar)Collateral Ligament
Annular Ligament
-stabilizes radial head against ulna

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19
Q

What does the HUJ and HRJ Lateral Collateral Ligament Complex do combined?

A

Restraint to varus
Restraint to combined varus + supination
Reinforces HRJ; limits distraction
Maintains posterolateral stability
Secures ulna to humerus (prevents dislocation)
Prevents forearm from rotating off humerus in valgus and supination during flexion from a fully extended position

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20
Q

HUJ and HRJ Axis of Motion

A

Centered in middle of trochlea on a line that intersects the longitudinal axis of the humerus
Carrying angle: Acute angle formed by long axis of humerus and forearm
-Normal:8-15 deg
-Cubitus valgus: >15 deg
-Cubitus varus: <5 deg

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21
Q

T/F Oblique axis results in a change in the relationship of the forearm and humerus when flexed.

A

True

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22
Q

Normal carrying angle with _______, ulna guided so that it’s in line with the same plane of the humerus when fully flexed.

A

Flexion

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23
Q

T/F Ulna medially guided from extension to flexion to put in the same plane as the humerus when fully flexed.

A

True

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24
Q

When cubitus valgus, going from extension to flexion, where does the forearm rest?

A

Forearm rest more medially when fully flexed

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25
Q

When cubitus varus, going from extension to flexion, where does the forearm rest?

A

Forearm rests laterally to humerus

26
Q

Why is the range of active flexion usually less than passive ?

A

Muscle bulk with contraction; decrease in approximation of joint surfaces

27
Q

When is there more elbow flexion AROM?

A

when forearm is supinated

28
Q

When is there less elbow flexion AROM?

A

when arm in neutral or pronated

29
Q

Brachialis
(Flexor)

A

Mobility
Large CSA and work capacity volume
MA greatest at 100 deg elbow flexion
Not affected by shoulder position
Activated with & without added resistance; slow & fast speeds

30
Q

Biceps Brachii
(Flexor)

A

Mobility
Smaller CSA but largest work capacity volume
MA greatest between 80-100 deg elbow flexion
-Small as it approaches full elbow extension
Activated without resistance IF elbow is supinated or in neutral (NOT in pronation)
-when resistance increases beyond weight of limb, biceps is active in ALL positions
Affected by shoulder position

31
Q

Brachioradialis
(flexor)

A

Stability
Smallest CSA, larger peak MA 100-120 deg elbow flexion
Not affected by shoulder position
Not active during:
-eccentric elbow flexion with supination
-slow, unresisted, concentric elbow flexion
Active during:
-Increased speed
-load is applied in forearm neutral OR full pronation

32
Q

Triceps Brachii
(extensor)

A

Mobility and Stability
Prime Mover for elbow extension
-Synergist to prevent elbow flexion when the biceps is acting as a supinator
Max torque at 90 deg elbow flexion
Long Head:
-Affected by shoulder position
-Active with heavy resistance to extension, with quick extension
Medial Head:
-Not affected by shoulder position
-Active in unresisted elbow extension, with heavy resistance to extension, with quick
extension
Lateral Head:
-Not affected by shoulder position
-Active with heavy resistance to extension, with quick extension

33
Q

Anconeus
(extensor)

A

Stability
15% contribution to elbow extension torque
Co-contracts with triceps to stabilize during functional tasks, dependent on load and speed

34
Q

Proximal Radioulnar Joint (PRUJ) Articulation

A

Radial notch of ulna
-annular ligament
Rim of radial head
HRJ

35
Q

PRUJ Open-Packed Position

A

70 deg elbow flexion, 35 deg supination

36
Q

PRUJ Close-Packed Position

A

5 deg supination, full extension

37
Q

Distal Radioulnar Joint (DRUJ) Articulation

A

Ulnar notch of radius
Articular disc
-Triangular fibrocartilage complex (TFCC)
Head of ulna

38
Q

DRUJ Open-Packed Position

A

10 deg supination

39
Q

DRUJ Close-Packed Position

A

5 deg supination

40
Q

PRUJ and DRUJ are _____________ linked

A

mechanically

41
Q

PRUJ Structure

A

Annular ligament
Quadrate Ligament
-Keeps radial head close to radial notch
-Checks pronation/supination
Oblique Cord
-Assists with preventing separation of radius and ulna

42
Q

DRUJ Structure

A

TFCC: divides DRUJ from the radiocarpal joint
-Proximal surface: articulates with ulnar head at DRUJ
-Distal surface: articulates with carpals
-Both surfaces are concave
Dorsal & Palmar Radioulnar ligaments

43
Q

DRUJ and PRUJ Interosseous Membrane

A

Stabilizes both
-Central band: prevents splaying
-Membranous portion
-Dorsal Oblique Cord
Help transmit loads Radius to Ulna

44
Q

DRUJ and PRUJ Axis of motion

A

Radius pivots around ulna during pronation and supination

45
Q

With pronation at the PRUJ, there is _______ roll and ______glide.

A

anterior; posterior
convex-concave

46
Q

With pronation at the DRUJ, there is _______ roll and ______glide.

A

anterior; anterior
concave-convex

47
Q

With supination at the PRUJ, there is _______ roll and ______glide.

A

posterior; anterior
Convex-concave

48
Q

With supination at the DRUJ, there is _______ roll and ______glide.

A

posterior; posterior
concave-convex

49
Q

Range of pronation is at its maximal when elbow is ….

A

extended

50
Q

Range of supination is at its maximal when elbow is ….

A

flexed

51
Q

Pronator Teres
(pronator)

A

Most efficient at 90 deg elbow flexion, between 40 deg supination & 40 deg pronation
Long head crosses elbow
MOBILITY for forearm pronation
STABILITY for elbow flexion

52
Q

Pronator Quadratus
(pronator)

A

Mobility
Most efficient at 90 deg elbow flexion, between 40 deg supination & 40 deg pronation
Active in:
-Unresisted & resisted pronation
-Slow and fast speed

53
Q

Supinator
(supinator)

A

Mobility
Peak torque achieved 40-50 deg of pronation
Single-joint muscle
Active in:
-Unresisted slow supination in all positions
-Unresisted fast supination when elbow is extended

54
Q

Biceps
(supinator)

A

Mobility
Peak torque achieved 40-50 deg of pronation
Activity:
-always evident when supination is performed against resistance
-during fast supination when elbow is flexed at 90 deg

55
Q

Integrated Stability - Pronator quadratus

A

Deep head active throughout pronation & supination to support DRUJ

56
Q

Integrated Stability - Extensor Carpi Ulnaris

A

Stabilizes head of ulnar during pronation and supination at DRUJ

57
Q

Integrated Stability - Extensor Carpi Radialis Brevis

A

-Active to stabilize DRUJ during pronation & supination
-Supports forearm for griping during forceful pronation
-Prime mover for wrist extension during supination

58
Q

Integrated Stability - Radioulnar Ligaments

A

Prevent separation of radius and ulna during loading
-allow approx. 5 mm of play
May contribute to force transmission from radius to ulna through DRUJ
-Dorsal: Taut in pronation
-Palmar: Taut in supination

59
Q

Integrated Stability - TFCC

A

Helps bind ulna and radius together
Provides long-axis stabilization of radius and ulna by acting as a cushion

60
Q

Integrated Stability - Interosseous membrane

A

Helps bind ulna and radius together
Provides long-axis stabilization of radius and ulna

61
Q

How is force distributed form the wrist to the humerus?

A

Radius –> Interosseous membrane –> Ulna –> Humerus