Chapter 6B- Harnessing and Controls for Body-Powered Devices Flashcards Preview

Atlas of Limb Prosthetics > Chapter 6B- Harnessing and Controls for Body-Powered Devices > Flashcards

Flashcards in Chapter 6B- Harnessing and Controls for Body-Powered Devices Deck (48)
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1
Q

What type of harnessing system is used for transradial amputees?

A

One-cable/ Single-control system

2
Q

What is another name for terminal devices?

A

Prehension devices

3
Q

What type of motion applies tension to the control cable?

A

Shoulder motion

4
Q

How much prehensile force is produced by each rubber band?

A

0.45 kg or 1lb

5
Q

what encases the control cable for most of its length?

A

Flexible stainless steel housing

6
Q

The upper end of the control cable attaches to what through what?

A

Attaches to the Triceps pad through the housing and crossbar assembly.

7
Q

Where does the distal end of the cable attach and through what?

A

Midforearm level of the prosthesis by the base plate and retainer

8
Q

What does the housing for the cable do?

A

Maintains a constant length of the control cable regardless of the angular attitude of the anatomic elbow joint

9
Q

How can you tell the housing is doing its job?

A

The amount of body motion to operate the terminal devices remains the same when the elbow is flexed at 135 degrees and fully extended.

10
Q

What is the standard harness for a unilateral adult transradial amputee composed of?

A

2.5 cm (1 in) wide Dacron webbing

11
Q

How is the webbing arranged for a standard harness for a unilateral adult transradial amputee?

A

Arranged to form a horizontally oriented figure of 8

12
Q

What is the purpose of the axilla loop?

A

To serve as an anchor for the two other straps

13
Q

Where is the axilla loop located?

A

Encircling the shoulder girdle on the non-amputated side

14
Q

What is another name for the anterior support strap?

A

Inverted Y suspensor

15
Q

Where is the anterior support strap located?

A

Originates at the axilla loop
Passes over the shoulder on the amputated side
Attaches to the anteroproximal margins of the triceps pad of the prosthesis.

16
Q

What is the primary purpose of the anterior support strap?

A

To resist displacement of the socket on the residual limb when the prosthesis is subjected to heavy loading

17
Q

Where does the control attachment strap originate and attach?

A

Originates at the axilla loop

Terminates at the proximal end of the prosthetic control cable

18
Q

What is the purpose of the control attachment strap?

A

to act as an extension of the control cable.

19
Q

Where is the control attachment strap located?

A

Between the spine and inferior angle of the scapula

20
Q

What anatomical movements creates the operation of the terminal device?

A

Scapular abduction

Shoulder flexion

21
Q

What is the name of the area where the axilla loop crosses itself?

A

The cross point

22
Q

What are the two attachment option for the cross point?

A

Sewn together

Stainless steel loop

23
Q

What is the name of the harness if a stainless steel ring is used at the cross point?

A

Transradial, Ring-type harness

24
Q

What is the advantage of a ring-type harness?

A

Less restrictive

25
Q

Where should the cross point be located?

A

Below the spinous process of C7 and slightly towards the non amputated side

26
Q

What is the primary body control motion for operating the terminal device of a transradial prosthesis?

A

Glenohumeral flexion

27
Q

What primary body control motion is used to operate the terminal device when needing to button a shirt or other movements close to midline with a transradial harness?

A

Biscapular abduction

28
Q

What is a disadvantage of the standard figure of 8 harness for transradial amputees related to the axilla loop?

A

Comfort- Need extra padding and worn over an undergarment

Tension creates excess axilla pressure- lead to skin irritation and possible neurotrophic changes

29
Q

When should a nonstandard transradial harness system be used?

A

When the patient is engaged in strenous work activities with continuous lifting of heavy objects

30
Q

What is another name for a nonstandard transradial harness?

A

Heavy-duty harness

Shoulder-saddle harness

31
Q

What is the difference between the heavy-duty harness and the standard harness?

A

When tension is applied it is distributed over the shoulder on the amputated side rather than the axilla

32
Q

Where is the leather shoulder saddle located?

A

Amputated side

33
Q

Where are two support straps on a shoulder saddle extended from, when using a heavy-duty harness?

A

The posterior portion of the shoulder saddle through D-rings

34
Q

Where are the D-rings located for the support straps of the shoulder saddle, when using a heavy-duty harness?

A

On the medial and lateral surfaces of the triceps pad

35
Q

Where do the two shoulder saddle support straps attach, when using a heavy-duty harness?

A

Anterior surface of the shoulder saddle.

36
Q

How is the shoulder saddle anchored?

A

A Chest strap

37
Q

What body controlled motions does the patient use to operate the heavy duty harness?

A

Glenohumeral flexion

Scapular abduction

38
Q

On bilateral transradial amputees, what is the difference between the harnessing?

A

The control attachment strap becomes the anterior support strap

39
Q

When using a step-up elbow hinge, what are the disadvantages?

A

Requires double the force

Excess pressure/discomfort on the volar or radial surface of the remaining transradial amputation.

40
Q

What modifications to the harnessing can be done to a step-up elbow hinge, to provide more comfort for the patient?

A

Split cable housing into proximal and distal segments (similar to transhumeral)

41
Q

Where is the proximal piece of the housing attached for a split cable designed harness of a short transradial amputee?

A

The triceps pad

42
Q

Where is the distal piece of the housing attached for a split cable designed harness of a short transradial amputee?

A

The prosthetic forearm

43
Q

For the modified harness of the step-up elbow hinge, where is the control cable exposed?

A

Anterior to the elbow joint

44
Q

What movement occurs when tension is applied to the control cable by the glenohumeral flexion?

A

Elbow flexion

45
Q

For sockets with anatomical suspension, what anatomical landmarks hold the transradial socket on?

A

Olecranon
Humeral Epicondyle
Antecubital fossa

46
Q

What does anatomical suspension eliminate in regards to the harnessing?

A

Triceps pad

Anterior Support Strap

47
Q

What does an anatomically suspended socket have for a harness?

A

Axilla Loop

Control attachment strap

48
Q

What is the disadvantage of using a anatomically suspended prosthesis?

A

Long-sleeved clothing is difficult to wear