Margarethe Caroline Eichler (born in 1808 or 1809; died 6 September 1843 in Berlin) was a German inventor, instrument maker and prostheses designer. She was the first woman in Prussia to receive a patent (for her leg prosthesis) and was also the inventor of the first practical modern hand prosthesis. Biography Caroline Eichler was born in 1808 or 1809, presumably in Nordhausen or Berlin, as the third daughter of painter Johann Gottlieb Eichler. In those days, young women were usually denied higher education opportunities or apprenticeships, and although no documentation has been found describing her schooling, her work demonstrates a knowledge of physics and technical mechanics. Around 1826 Eichler was working as a nanny and later worked as a nurse. Life While working as a nurse, Eichler was struck by the misery of amputees and "found myself particularly stimulated when, in the course of my business of nursing, I noticed the manifold sufferings of such unfortunate people. (...) So I pursued the idea of (...) inventing and representing a machine that was capable of making the suffered loss of the leg of the person concerned less sensitive and detrimental." In 1832, Eichler designed and constructed a prosthetic leg with a knee joint, for which she received a 10-year patent on 23 November 1833, the first woman in Prussia to receive a patent. (Until Eichler, a leg prosthesis was rigid; "a stilted foot, an immovable piece of wood that was strapped to the stump, was common. Carpenters, blacksmiths and saddlers built it.") She also received patents for the Russian Empire and, on 13 January 1835, for the Kingdom of Bavaria as well. Her leg and foot patent allowed her to be the exclusive manufacturer and seller of her prosthetic for ten years:'The unmarried Karoline Eichler here herself is on November 23, 1833 a ten consecutive years, (...), and valid for the entire scope of the Prussian state: on a, in its entire composition for new and peculiarly recognized artificial leg for Replacement of the upper and lower leg, given,' reports the Allgemeine Preussische Staats-Zeitung of December 1, 1833.Eichler advertised her prosthetic leg and foot in a self-published text, in which she proudly announced that her design had passed inspection by Johann Friedrich Dieffenbach, head of surgery at Berlin's Charité Hospital, who reported on the successful use of the prosthesis for one of his patients and "expressly praised the design." She continued