CPT Prosthetic Fabrication & Assembly Techniques 1 — Questions and Answers
Question 1: What is the purpose of vacuum forming in prosthetic socket fabrication?
- To reduce limb pressure
- To remove moisture
- To shape the socket over a positive model (Correct answer)
- To align components
Correct answer: To shape the socket over a positive model
Vacuum forming is a manufacturing process where a heated sheet of plastic material is stretched over a positive mold (the positive model of the residual limb) and then a vacuum is applied. This process pulls the softened plastic tightly against the mold, precisely shaping it to create a custom-fitting prosthetic socket.
Question 2: Which material is commonly used for lamination in prosthetics?
- Aluminum
- Polyurethane foam
- Carbon fiber (Correct answer)
- Copper
Correct answer: Carbon fiber
Carbon fiber is widely used in prosthetic lamination due to its exceptional strength-to-weight ratio and stiffness. When combined with resins, it creates lightweight yet incredibly durable prosthetic components, such as sockets and frames, that can withstand significant forces and provide long-lasting support.
Question 3: What tool is typically used to align lower limb prosthetic components?
- Drill press
- Bench vise
- Alignment jig (Correct answer)
- Vacuum pump
Correct answer: Alignment jig
An alignment jig is a specialized tool used by prosthetists and technicians to precisely position and secure prosthetic components (like the socket, knee unit, and foot) relative to each other. This ensures that the prosthesis is correctly aligned biomechanically, which is crucial for optimal gait, comfort, and function for the user.
Question 4: Why is the positive model critical in prosthetic socket design?
- It replaces the liner
- It provides structural reinforcement
- It guides socket shape and fit (Correct answer)
- It assists in thermal regulation
Correct answer: It guides socket shape and fit
The positive model is a replica of the patient's residual limb, created from a cast. It serves as the foundational mold over which the prosthetic socket is fabricated, ensuring that the final socket precisely matches the contours of the limb for an intimate, comfortable, and functional fit.
Question 5: What is the benefit of using a modular prosthetic system?
- They are less durable
- They are fixed permanently
- They allow easy adjustments and repairs (Correct answer)
- They require no tools
Correct answer: They allow easy adjustments and repairs
Modular prosthetic systems are designed with interchangeable components that can be easily assembled, disassembled, and replaced. This modularity allows prosthetists to make fine-tuned adjustments to alignment, height, and component selection, and facilitates efficient repairs or upgrades without needing to replace the entire prosthesis.
Question 6: Which component connects the prosthetic socket to the foot in a lower limb prosthesis?
- Strap
- Foot shell
- Pylon (Correct answer)
- Cushion liner
Correct answer: Pylon
The pylon is the structural component that connects the prosthetic socket, which encases the residual limb, to the prosthetic foot. It acts as the "shin" or "leg" of the prosthesis, providing support, transmitting forces, and often incorporating features for height adjustment and shock absorption.
CPT Prosthetic Fabrication & Assembly Techniques 1
What is the purpose of vacuum forming in prosthetic socket fabrication?