Upper Extremity Problem Solving

Question 1

Describe the primary difference between the Muenster style socket and the Northwestern style self-suspending socket.

Answer 1

• suspension is obtained through a tight AP dimension in Muenster sockets
• Suspension is obtained through Supra epicondylar (ML) dimension in the Northwestern socket

Question 2

Which prehensile pattern is most commonly used with prosthetic mechanical hands?

Answer 2

Three jaw chuck (palmer) prehension

Question 3

Which prehensile pattern is most commonly used with prosthetic hooks?

Answer 3

Lateral prehension

Question 4

List five transradial hinges with corresponding limb length and an indication for each.

Answer 4

• flexible - long, retains pronation and supination
• Rigid single axis - mid length, protects against torsion
• Polycentric - short, reduces cubital bunching
• step up - short, increase prosthetic forearm flexion
• stump activated locking - very short, increase prosthetic forearm flexion (harnessed and cable similar to an transhumeral prosthesis)

Question 5

What type of cable system is used for the transhumeral body powered prosthesis?

Answer 5

Fair-lead (split housing)

Question 6

What shoulder motions are necessary to activate the positive locking elbow of a transhumeral prosthesis?

Answer 6

• depression
• extension
• abduction

Question 7

When it is necessary for a transradial amputee to open the terminal device close to the body, the body control motion used is:

Answer 7

Biscapular abduction

Question 8

The basic body control motion for functioning either the terminal device or prosthetic elbow in an upper extremity prosthesis is:

Answer 8

Shoulder flexion

Question 9

Name this component:

Answer 9

Bowden Single Control Cable System

Question 10

What type of joint is depicted in this image?

Answer 10

Single Axis Rigid Hinge

Question 11

Name this component:

Answer 11

Fair lead Split Cable Housing, dual control

Question 12

What motions might this patient employ to operate a body powered prosthesis?

Answer 12

• Bi/uniscapular abduction
  
  • note: biscapular motion not possible with IST
• Uniscapular elevation
  
  • capture excursion during shoulder elevation
• chest expansion
  
  • tight belt around chest to capture excursion during deep breath
• sound-side humeral flexion/extension
  
  • capture excursion from movement of sound side humerus
• neck flexion/jaw dropping
  
  • nudge control
• trunk lean
  
  • capture excursion from strap attached to waist belt

Question 13

Identify the component attached to this elbow and provide its function.

Answer 13

Forearm lift assist - reduce force needed to flex elbow

Question 14

Identify this harness.

Answer 14

Figure of 9