Margarethe Caroline Eichler (born in 1808 or 1809; died 6 September 1843 in Berlin) was a German inventor, instrument maker and prostheses designer.

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.

(...) 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.

(Until Eichler, a leg prosthesis was rigid; "a stilted foot, an immovable piece of wood that was strapped to the stump, was common.

[1] On 30 October 1837, Caroline Eichler married a man seven years her junior, the mechanic Friedrich Eduard Carl Krause[1] from Bielefeld.

[2] Earlier designs either had no knee joint or, like the artificial legs described by the surgeon Ambroise Paré in the 16th century, had to be operated by pulling a cord.

[1][4] In contrast, Eichler designed her prosthetic to fit on the stump after it was tightly wrapped with bandages and then a padded leather funnel.

Then the prosthesis was pulled over the bandages and hung over the shoulder by a strap that was attached to the front and back of the funnel to avoid unnecessary pressure on the thigh stump.

It moved using a combination of gut strings and pressure-loaded coil springs, which, according to Eichler, were designed to correspond to human tendons and muscles.

Her mechanism allowed the knee to bend while walking, and the springs brought the leg back to its extended starting position when it was lifted.

In contrast to the iron hands of Renaissance times, the prosthesis had an opposable thumb that enabled a forceps grip with a sixth slider.

The hand could easily be dismantled into its individual parts to simplify repairs and keep costs down, but the purchase price was quite high at 75 to 100 thalers.