Chapter Twelve: Biomechanics of the upper limb Flashcards Preview

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Flashcards in Chapter Twelve: Biomechanics of the upper limb Deck (46)
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1
Q

What type of joint is the interphalangeal joint?

A

Uniaxial joint with one degree of freedom, allowing motion in one plane.

2
Q

What’s the normal ROM of flexion and extension for the elbow?

A

0-150

3
Q

What is the normal ROM of pronation and supination for the elbow?

A

75-80 degrees

4
Q

What is the normal ROM of flexion of the wrist?

A

80-85 degrees

5
Q

What is the normal ROM of extension of the wrist/

A

70 degrees

6
Q

What is the radial deviation ROM at the wrist/

A

20 degrees

7
Q

What is the ulnar deviation ROM at the wrist?

A

30 degrees

8
Q

What degree of a flexion contracture at the elbow causes functional impairmenmt

A

Motion loss of greater than 30 degrees

9
Q

What type of joint is the shoulder/

A

Ball and socket

10
Q

A loss of elbow motion of 30 degrees, 45 degrees, and 60 degrees can lead to the loss of hand function by what percent?

A

28%
39%
60%

11
Q

Wrist extension i synergistic to what?

A

Finger flexion and increases the length in the finger flexor muscle

12
Q

Wrist flexion is synergistic to what?

A

Finger extension

13
Q

What are the static element of the joints?

A

Articular
Capsular
Ligamentous
Intraarticular pressure components

14
Q

What are the dynamic elements of joints?

A

Muscle activity.

15
Q

The shoulder relies on what for stability?

A

capsular
Ligamentous
Dynamic muscular activity

16
Q

The elevation of the arm by the deltoid muscle is countered by what?

A

Depression action of the anterior and posterior rotator cuff musculature.

17
Q

Joint stability of the shoulder can be enhanced by what/

A

The barrier effect of the contracted muscle.

18
Q

Which muscle in the shoulder is a dynamic stabilizer, acting as an anterior barrier to resist anteroinferior humeral head displacement with abduction and external rotation?

A

Subscapularis

19
Q

What are the roles of the long and short head of the biceps in the shoulder/

A

Anterior stabilizers of the glenohumeral joint with the arm in abduction and external rotation.
Their role increases with decreased shoulder stability.
They prevent anterior head displacement

20
Q

What is the primary valgus stabilizer of the elbow?

A

Anterior bundle of the Medial collateral ligament (MCL)

21
Q

What serves as a secondary joint stabilizer in the elbow?

A

Radial head.

22
Q

What is a major stabilizing structure for both rotational and varus instability?

A

lateral ulnar collateral ligament

23
Q

What part of the ulna is important in providing joint stability in the elbow?

A

Proximal ulna articular surface
The greater sigmoid notch resists valgus stress
The distal portion of the joint surface resists varus stress.
The coronoid process prevents posterior subluxation of the elbow joint, especially with the elbow in extension.

24
Q

What kind of joint is the forearm joint?

A

Bicondylar joint: with the proximal radioulnar joint and distal radioulnar joint serving as the condyles.

25
Q

What is the motion at the forearm?

A

A pivoting behavior, with total roation

26
Q

What are the principle constraints against anterior translation of the radius relative to the ulna in the forearm?

A

Palmar radioulnar ligment and dorsal distal radioulnar joint capsule

27
Q

What are the principle constraints against posterior translation of the radius relative to the ulna in the forearm?

A

Dorsal radioulnar ligament and the anterior distal radiulnar joint capsule.

28
Q

what are the most critical ligaments of the wrist, that accept the greatest load and strain prior to failure?

A

Scapholunate and lunotriquetral ligaments

29
Q

What ligaments play an important role in stabilization in the hand?

A

The collateral ligaments

30
Q

What does prehension mean?

A

All the function that are put into play when an object is grasped by the hands-intent, permanent sensory control, and a mechanism of grip.
It requires a hand be able to approach, grasp, and release an object.

31
Q

What are the seven basic hand maneuvers?

A
Precision pinch (terminal pinch)
Oppositional pinch (subterminal pinch)
Key pinch
Directional grip (chuck grip)
Hook grip
Power grasp
span grasp
32
Q

What is the precision pinch?

A

Flexion at the DIP joint of the index and IP joint of the thumb. The ends of the fingernails are brought together, as in lifting a paperclip.

33
Q

What is oppositional pinch?

A

The pulp of the index and thumb are brought together with the DIP joints extended. This allows for generation of force through thumb opposition, first dorsal interosseous contraction and index profundus flexion.

34
Q

What is key pinch?

A

The humb is adducted to the radial side of the middle phalanx of the index finger. It requires a stable post, usually an index finger and an MP joint, which can resist the thumb adduction force.

35
Q

What is directional grip?

A

The thumb and the index and long fingers come together to surround a cylindrical object. When using this grip, a rotational and axial force usually is applied to the held object (ex: screwdriver)

36
Q

What is the hook grip?

A

This requires finger flexion at the IP joints and extension at the MP joints. It is the only type of functional grasp that does not require thumb function. This grip is used when lifting a suitcase.

37
Q

What is power grasp?

A

The fingers are fully flexed while the thumb is flexed and opposed over the other digits, as in holding a baseball bat, force is applied through the fingers into the palm.

38
Q

What is the span grasp?

A

The DIP and PIP joints flex to approximately 30 degrees and the thumb is abducted. Force is generated between the thumb and fingers as opposed to power grasp, where force is generated between the fingers and the palm. Stability is required at the thumb MP and IP. This grip is used to lift cylindrical objects.

39
Q

Loss of what will make fine motor movements negligible?

A

Median nerve function
Thumb sensation
Thenar function

40
Q

What are important for digitoplamar grip?

A

Ulnar nerve function
Ring-small finger units
Flexion and sensation in the ulnar digiits

41
Q

What joint is the thumb?

A

Trapeziometacarpal joint

42
Q

What ROM of pronation and flexion does the thumb have?

A

80 degrees

43
Q

opposition of the thumb is the result of what?

A

Angulatory motion, which is produced through abduction at the TMC joint, flexion and rotation of the TMC and MP joints.

44
Q

What muscles are involved in opposition?

A

Abductor pollicis brevis, opponens pollicis, and superficial head of the flexor pollicis brevis.

45
Q

What are the muscles that are antagonists to thumb opposition?

A
Extensor pollicis longus (EPL)
Adductor pollicis (ADP)
46
Q

The MP joint of the thumb is what kind of joint?

A

Ball and socket

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