Chapter Twelve: Biomechanics of the upper limb

Question 1

What type of joint is the interphalangeal joint?

Answer 1

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

Question 2

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

Answer 2

0-150

Question 3

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

Answer 3

75-80 degrees

Question 4

What is the normal ROM of flexion of the wrist?

Answer 4

80-85 degrees

Question 5

What is the normal ROM of extension of the wrist/

Answer 5

70 degrees

Question 6

What is the radial deviation ROM at the wrist/

Answer 6

20 degrees

Question 7

What is the ulnar deviation ROM at the wrist?

Answer 7

30 degrees

Question 8

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

Answer 8

Motion loss of greater than 30 degrees

Question 9

What type of joint is the shoulder/

Answer 9

Ball and socket

Question 10

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

Answer 10

28%
39%
60%

Question 11

Wrist extension i synergistic to what?

Answer 11

Finger flexion and increases the length in the finger flexor muscle

Question 12

Wrist flexion is synergistic to what?

Answer 12

Finger extension

Question 13

What are the static element of the joints?

Answer 13

Articular
Capsular
Ligamentous
Intraarticular pressure components

Question 14

What are the dynamic elements of joints?

Answer 14

Muscle activity.

Question 15

The shoulder relies on what for stability?

Answer 15

capsular
Ligamentous
Dynamic muscular activity

Question 16

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

Answer 16

Depression action of the anterior and posterior rotator cuff musculature.

Question 17

Joint stability of the shoulder can be enhanced by what/

Answer 17

The barrier effect of the contracted muscle.

Question 18

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?

Answer 18

Subscapularis

Question 19

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

Answer 19

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

Question 20

What is the primary valgus stabilizer of the elbow?

Answer 20

Anterior bundle of the Medial collateral ligament (MCL)

Question 21

What serves as a secondary joint stabilizer in the elbow?

Answer 21

Radial head.

Question 22

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

Answer 22

lateral ulnar collateral ligament

Question 23

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

Answer 23

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.

Question 24

What kind of joint is the forearm joint?

Answer 24

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

Question 25

What is the motion at the forearm?

Answer 25

A pivoting behavior, with total roation

Question 26

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

Answer 26

Palmar radioulnar ligment and dorsal distal radioulnar joint capsule

Question 27

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

Answer 27

Dorsal radioulnar ligament and the anterior distal radiulnar joint capsule.

Question 28

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

Answer 28

Scapholunate and lunotriquetral ligaments

Question 29

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

Answer 29

The collateral ligaments

Question 30

What does prehension mean?

Answer 30

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.

Question 31

What are the seven basic hand maneuvers?

Answer 31

``` Precision pinch (terminal pinch) Oppositional pinch (subterminal pinch) Key pinch Directional grip (chuck grip) Hook grip Power grasp span grasp ```

Question 32

What is the precision pinch?

Answer 32

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.

Question 33

What is oppositional pinch?

Answer 33

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.

Question 34

What is key pinch?

Answer 34

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.

Question 35

What is directional grip?

Answer 35

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)

Question 36

What is the hook grip?

Answer 36

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.

Question 37

What is power grasp?

Answer 37

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.

Question 38

What is the span grasp?

Answer 38

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.

Question 39

Loss of what will make fine motor movements negligible?

Answer 39

Median nerve function Thumb sensation Thenar function

Question 40

What are important for digitoplamar grip?

Answer 40

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

Question 41

What joint is the thumb?

Answer 41

Trapeziometacarpal joint

Question 42

What ROM of pronation and flexion does the thumb have?

Answer 42

80 degrees

Question 43

opposition of the thumb is the result of what?

Answer 43

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

Question 44

What muscles are involved in opposition?

Answer 44

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

Question 45

What are the muscles that are antagonists to thumb opposition?

Answer 45

``` Extensor pollicis longus (EPL) Adductor pollicis (ADP) ```

Question 46

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

Answer 46

Ball and socket