CPT Prosthetic Components & Technology 2

Question 1

Microprocessor-controlled prosthetic knees (MPKs) use onboard sensors primarily to assess which variables in real time?

Accepted Answer

Angular velocity, acceleration, and load data to modulate hydraulic resistance

Answer

MPKs use gyroscopes, accelerometers, and load cells to continuously assess limb kinematics, then adjust hydraulic or pneumatic resistance to optimize gait.

Question 2

What type of wrist unit allows a transradial prosthesis user to pre-position the terminal device in multiple planes of rotation?

Accepted Answer

Flexion-rotation wrist unit (flexion/extension and rotation)

Answer

A flexion-rotation wrist unit provides both wrist flexion/extension and forearm rotation positioning, enabling the user to pre-set the terminal device for varied tasks.

Question 3

Which suspension method for a transtibial prosthesis relies on a urethane or silicone liner rolled onto the residual limb, with a locking pin that engages a clutch mechanism in the socket?

Accepted Answer

Pin/lock (lanyard) suspension

Answer

Pin/lock suspension uses a distal locking pin on the liner that clicks into a clutch or shuttle lock built into the distal socket, providing reliable mechanical suspension.

Question 4

Elevated vacuum suspension (EVS) systems improve prosthetic suspension and residual limb health primarily by:

Accepted Answer

Maintaining negative pressure within the socket to reduce volume fluctuation and pistoning

Answer

EVS actively evacuates air from the socket interface, creating consistent negative pressure that stabilizes residual limb volume, reduces pistoning, and improves proprioception.

Question 5

A myoelectric prosthetic hand uses surface electromyography (sEMG) signals from residual limb muscles to control the hand. Which muscle pair is most commonly used for transradial myoelectric control?

Accepted Answer

Wrist flexors and wrist extensors

Answer

The wrist flexors and wrist extensors of the residual forearm are the primary electrode sites for transradial myoelectric control, as they retain voluntary muscle function distal to the amputation.

(CPT) Certified Prosthetic Technician Practice Test

(CPT) Certified Prosthetic Technician Practice Test

CPT Prosthetic Components & Technology 2