Here's why:
* Prostheses are inherently designed to be active in some way: Even a simple passive prosthesis like a hook for an arm amputation relies on the user's muscle movement to activate its function (grasping).
* "Passive" in prosthetics often refers to a specific component: For example, a "passive hand" in a prosthetic arm might be a component that simply opens and closes based on the user's wrist movement, rather than using motors or electronics for active control.
To understand the functionality of prosthetics, it's more helpful to consider them by their degree of control:
* Passive Prostheses: These are the simplest type. They are not controlled by any electronic or mechanical components. Examples include hooks and cosmetic limbs.
* Body-Powered Prostheses: These prostheses are controlled by the user's body movements, typically through cables and harnesses. Examples include traditional prosthetic arms and legs.
* Myoelectric Prostheses: These prostheses are controlled by electrical signals from the user's muscles, detected by electrodes. This allows for more precise control than body-powered prostheses.
* Hybrid Prostheses: These combine elements of body-powered and myoelectric control.
* Robotic Prostheses: These are highly advanced prostheses with sophisticated control systems and multiple degrees of freedom.
Therefore, it's more accurate to discuss the different types of prostheses based on their control mechanisms and functionality.
If you are interested in learning more about a specific type of prosthetic device, please provide more context or details about what you are looking for.