The tag implication #40409 prosthetic_hand -> prosthetic has been rejected.

Reason: Prosthetic hands are prosthetics.

EDIT: The tag implication prosthetic_hand -> prosthetic (forum #314332) has been rejected by @bitWolfy.

Technically, prosthetic_hand is different from prosthetic_arm, but I'm not convinced that the difference is important enough for the sake of tagging.
They seem to be used interchangeably: from just the hand, to the elbow down, to the entire arm being replaced – both tags have examples of each.

The tag implication prosthetic_hand -> prosthetic (forum #314332) has been rejected by @bitWolfy.

This one was actually supposed to be approved. Oops.