The ear is an inverted fetus that maps to our entire body

French physician Paul Nogier (1908-1996) is considered to be a pioneer of auriculotherapy, a modern form of acupuncture in which the human ear maps to the entire body. In 1957, Nogier suggested that the ear not only resembles an inverted fetus but that parts of it have a point-to-point relationship to the corresponding larger part of our anatomy.

Weird Universe quotes the book Anatomies: the human body, its parts and the stories they tell (2014) by Hugh Aldersey-Williams:

In the 1950s, a French doctor and acupuncturist named Paul Nogier noted that it resembles a curled human foetus (the lobe of the ear represents the head and the interior fold known as the antihelix the spine of the foetus in this case). The scheme of alternative medicine that he devised based on this resemblance is known as auriculotherapy. The patient's ear is seen as a homunculus or map of the whole body, with stimulation at different points on it being used to treat ailments in corresponding parts of the body.