Heroes often get mauled, slashed and even mutilated. Doctors in the Healiopolis eventually started designing replacement body parts for that heroes, the first ever built wooden leg were two surgeons called "Arento Prothasos" and "Lemin Mateses". They named their invention "protheses fake leg" and started selling them to doctors and other medical workers around Godville. Time passed and many fake limbs were invented, heroes are not fit to remember more than one word if beer or gold is not involved, so they called this new brand of fake limbs simply protheses.
There was a glassblower whom got involved with surgeons by chance. As she assisted a teeth reconstruction she realized the lack of jaw protheses, thus she decided to take matters into her own hands and create a new protheses. A discarded skull served as the model and the facial surgery academy of Godville approved the implementation of this new artifact. But alas this was a glass jaw, and even some ill-aimed tomatoes may obliterate the protheses. Even though it's medical use only lasted a few weeks, traders still buy this artifacts make for good soup bowls. Or so say the surveys.