Wrist Disarticulation

Question 1

The wrist disarticulation includes an intact radius and ulna; the articular surfaces remain intact and the residuum is quite long. Because of this:”

Answer 1

• the patient experiences an improved amount of dispersion of pressures in the socket due to the large surface area of the residual limb
• the wrist unit is placed at the distal end of the socket, leaving very little distance between the socket and the terminal device. This provides the residual limb with a biomechanical advantage due to its length.
• the length may also create a problem with cosmetics because the wrist and terminal device must be located distal to the socket. The overall finished prosthetic length may exceed the length of the thumb tip on the sound side.
• the wrist disarticulation allows excellent ROM in flexion and extension as well as pronation and supination.

Question 2

The socket can be contoured to capture the shape of the residual limb on the palmar and dorsal aspects of the forearm. This is known as the:

Answer 2

Screwdriver Effect

Question 3

The wrist disarticulation prosthesis can be suspended a number of ways. The preferred form of suspension is:

Answer 3

Supra-styloid Suspension

Question 4

The wrist disarticulation socket that is suspended by a Supra-epicondylar style socket will prevent axial rotation but allow pronation and supination.

Answer 4

False

Question 5

The basic disarticulation design considers the following relevant prosthetic issues:

Answer 5

• facilitation of pronation and supination of terminal device
• suspension
• harness/cable system
• selection of wrist shape