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

Question 1

What type of harnessing system is used for transradial amputees?

Answer 1

One-cable/ Single-control system

Question 2

What is another name for terminal devices?

Answer 2

Prehension devices

Question 3

What type of motion applies tension to the control cable?

Answer 3

Shoulder motion

Question 4

How much prehensile force is produced by each rubber band?

Answer 4

0.45 kg or 1lb

Question 5

what encases the control cable for most of its length?

Answer 5

Flexible stainless steel housing

Question 6

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

Answer 6

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

Question 7

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

Answer 7

Midforearm level of the prosthesis by the base plate and retainer

Question 8

What does the housing for the cable do?

Answer 8

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

Question 9

How can you tell the housing is doing its job?

Answer 9

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

Question 10

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

Answer 10

2.5 cm (1 in) wide Dacron webbing

Question 11

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

Answer 11

Arranged to form a horizontally oriented figure of 8

Question 12

What is the purpose of the axilla loop?

Answer 12

To serve as an anchor for the two other straps

Question 13

Where is the axilla loop located?

Answer 13

Encircling the shoulder girdle on the non-amputated side

Question 14

What is another name for the anterior support strap?

Answer 14

Inverted Y suspensor

Question 15

Where is the anterior support strap located?

Answer 15

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.

Question 16

What is the primary purpose of the anterior support strap?

Answer 16

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

Question 17

Where does the control attachment strap originate and attach?

Answer 17

Originates at the axilla loop

Terminates at the proximal end of the prosthetic control cable

Question 18

What is the purpose of the control attachment strap?

Answer 18

to act as an extension of the control cable.

Question 19

Where is the control attachment strap located?

Answer 19

Between the spine and inferior angle of the scapula

Question 20

What anatomical movements creates the operation of the terminal device?

Answer 20

Scapular abduction

Shoulder flexion

Question 21

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

Answer 21

The cross point

Question 22

What are the two attachment option for the cross point?

Answer 22

Sewn together

Stainless steel loop

Question 23

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

Answer 23

Transradial, Ring-type harness

Question 24

What is the advantage of a ring-type harness?

Answer 24

Less restrictive

Question 25

Where should the cross point be located?

Answer 25

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

Question 26

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

Answer 26

Glenohumeral flexion

Question 27

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?

Answer 27

Biscapular abduction

Question 28

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

Answer 28

Comfort- Need extra padding and worn over an undergarment | Tension creates excess axilla pressure- lead to skin irritation and possible neurotrophic changes

Question 29

When should a nonstandard transradial harness system be used?

Answer 29

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

Question 30

What is another name for a nonstandard transradial harness?

Answer 30

Heavy-duty harness | Shoulder-saddle harness

Question 31

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

Answer 31

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

Question 32

Where is the leather shoulder saddle located?

Answer 32

Amputated side

Question 33

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

Answer 33

The posterior portion of the shoulder saddle through D-rings

Question 34

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

Answer 34

On the medial and lateral surfaces of the triceps pad

Question 35

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

Answer 35

Anterior surface of the shoulder saddle.

Question 36

How is the shoulder saddle anchored?

Answer 36

A Chest strap

Question 37

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

Answer 37

Glenohumeral flexion | Scapular abduction

Question 38

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

Answer 38

The control attachment strap becomes the anterior support strap

Question 39

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

Answer 39

Requires double the force | Excess pressure/discomfort on the volar or radial surface of the remaining transradial amputation.

Question 40

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

Answer 40

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

Question 41

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

Answer 41

The triceps pad

Question 42

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

Answer 42

The prosthetic forearm

Question 43

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

Answer 43

Anterior to the elbow joint

Question 44

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

Answer 44

Elbow flexion

Question 45

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

Answer 45

Olecranon Humeral Epicondyle Antecubital fossa

Question 46

What does anatomical suspension eliminate in regards to the harnessing?

Answer 46

Triceps pad | Anterior Support Strap

Question 47

What does an anatomically suspended socket have for a harness?

Answer 47

Axilla Loop | Control attachment strap

Question 48

What is the disadvantage of using a anatomically suspended prosthesis?

Answer 48

Long-sleeved clothing is difficult to wear