The Hanger Leg
In 1861, 18 year old engineer James Edgar Hanger enlisted in the confederate army. Only two days after signing up, he was on the operating table, the first amputee of the war. A talented engineer, he made a replacement leg for himself in his Virginia home, shortly after which he filed for a patent with the confederate government. This leg had a spring and a flexible piece of metal inside to allow the knee to bend slightly, creating the first working above the knee prosthetic.
He went on to found a company, Hanger Incorporated, a billion dollar corporation which still manufactured prosthetics to this day.
*The man in the photo is J. E. Hanger