Week 4

Question 1

What are the two basic cable controls used in UE prosthetics?

Answer 1

Housing fair lead-split housing at the elbow

Bowden Cable-continuous housing across the elbow

Question 2

Who is the housing fair lead primarily used for?

Answer 2

Transhumeral, elbow disarticulations and very short transradials.

Question 3

What does the housing fair lead do?

Answer 3

Flexes the elbow when the elbow is unlocked
Flex elbow for a split socket design with residuum activated outside locks
To augment elbow flexion for split socket with step-up hinges.

Question 4

What motions does the housing fair leads harness control?

Answer 4

Humeral flexion

Bi-scapular abduction and protraction

Question 5

What is the Bowden Cable mostly used for?

Answer 5

Transradials

Question 6

What are two aspects specific to the Bowden cable?

Answer 6

Continuous house across the elbow

Tension on the cable has no impact on the elbow flexion

Question 7

What is the shoulder harness used for?

Answer 7

carrying heavy loads

patient’s who cannot tolerate the full axillary loop for actuation

Question 8

What are three aspects of the bilateral figure 8 harness?

Answer 8

No axillary loop
The delto-pectoral suspension straps are connected to the cross point
An elastic cross strap is added to prevent upward migration

Question 9

When is the figure 9 harness used?

Answer 9

For self suspending sockets like the muenster

Question 10

What are two aspects specific to the figure 9 harness?

Answer 10

It does not used the delto-pectoral suspension strap

The cross bar attaches to the mid posterior proximal brim of the socket

Question 11

Where is the crosspoint of the harness supposed to be?

Answer 11

Inferior to C7

Slightly towards the non-amputated side

Question 12

What is the difference between the crosspoint and the Northwest ring?

Answer 12

The ring allows for more freedom of movement

Question 13

Where is the northwest ring positioned?

Answer 13

Inferior to C7

Slightly towards the non-amputated side

Question 14

What does BAHA stand for?

Answer 14

Bio-mechanically aligned harness anchor

Question 15

What is the BAHA?

Answer 15

A high strength, lightweight, non-metallic harness component.

Question 16

What does the BAHA want to improve?

Answer 16

The biomechanics of the figure 8 harness

Question 17

How does the BAHA improve the biomechanics of the harness?

Answer 17

Optimizes the harnesses axilla angle

Provides a more efficient cable control pathway

Question 18

Where should the BAHA be positioned on the body?

Answer 18

Inferior to C7

Slightly towards the non-amputated side

Question 19

What are the four types of TR elbow joints?

Answer 19

Flexible
Rigid
Step up
Locking

Question 20

What is the Flexible TR elbow joint made of?

Answer 20

Fabric
Leather
Metal
Dacron Webbing

Question 21

What does the flexible TR elbow joint allow?

Answer 21

Maintain 50% of rotation

Free pronation and supination

Question 22

What are the two types of Rigid TR elbow joints?

Answer 22

Single axis and Polycentric

Question 23

What does the single axis Rigid TR elbow joint do?

Answer 23

Stabilizes the socket preventing pronation and supination

Protection of the residual limb against torque

Question 24

What are the advantages of the polycentric Rigid TR elbow joint?

Answer 24

Increased distance from epicondyle axis to anterior socket trim
Limited tissue bunching in the bicipital fold
Increased elbow flexion ROM

Question 25

Who are Rigid Friction Joints used for?

Answer 25

Very short TR or elbow disarticulation pediatric amputees

Question 26

What does the Rigid Friction Joint function as?

Answer 26

Transhumeral prosthesis

Question 27

What does the Rigid Friction Joints allow?

Answer 27

Positioning of elbow flexion/extension for small children

Question 28

When are step-up joints used?

Answer 28

Split Socket Very short TR <35% Limited ROM Patient with socket with high anterior trimlines

Question 29

What are the advantages of the Step-up joint?

Answer 29

Allows increased flexion beyond 90 degrees. | Allows strong flexion with limited ROM

Question 30

What is the Step-up joint geared at?

Answer 30

2:1 constant ratio

Question 31

What is the sliding variable ration step-up joint?

Answer 31

Varies the amount of force needed throughout the ROM. Initial flexion 1:1 Higher ratio mid-range Less at end of range

Question 32

When is the Residual limb activated locking hinge used?

Answer 32

Very short TR with split socket Inadequate strength ROM Residual limb surface area

Question 33

What cable is used with the Residual limb Activated locking hinge?

Answer 33

Split housing fair-lead control cable

Question 34

What formula is used to determine Bilateral length?

Answer 34

Carlyle formula

Question 35

What is the humerus length based on the Carlyle formula?

Answer 35

.19 x Body Height

Question 36

What is the forearm length based on the Carlyle Formula?

Answer 36

.21 x Body Height

Question 37

What two measurements make up the forearm length?

Answer 37

Lateral Epicondyle to styloid | Styloid to thumb tip

Question 38

What is the ratios of a quadri-membral amputation for the forearm.

Answer 38

Forearm=.19/.21 x measured humerus length (Apt)

Question 39

Who are the flexible hinge joints for?

Answer 39

Long Trans-radial amputation Wrist disarticulation Trans-carpal amputation

Question 40

Where is the proximal and distal attachment of the flexible hinge joint?

Answer 40

proximal-triceps pad | distal-prosthetic forearm

Question 41

What is the disadvantage of the single axis Rigid TR elbow joint?

Answer 41

Without proper alignment patient will not be able to maintain normal ROM for elbow flexion and extension

Question 42

Who are Rigid hinges made for/

Answer 42

Amputation at or above mid forearm

Question 43

Who are single axis hinges made for?

Answer 43

Short trans-radial patients

Question 44

Who are polycentric hinges made for?

Answer 44

Short trans-radial | Very short trans-radial

Question 45

For a Residual limb-activated locking hinge, what produces elbow flexion?

Answer 45

Glenohumeral flexion

Question 46

What are the two types of step up hinges?

Answer 46

Sliding action-requires split action cable | Geared-Can use Bowden Cable