Foreign bodies is a medical collective term for objects that do not belong in a human body. For example, operating material accidentally left behind after a surgical procedure, an object that has been swallowed, or a splinter of wood in the skin.
Prostheses are replacements, extensions, artificial additions to our bodies.
The English word prosthese comes from the Greek prosthesis and means "to put something against ", "to add something to" ,"to put something behind".
Pros = at, behind, against.
Tithèmi = I place.
In the French word prothèse and the Dutch prothese the first 's' was accidentally omitted.
Pros was confused with pro.
In this capacity it means performance.
An exhibition, therefore.