Until the middle of the Renaissance, there was an integrated view of religion, science and astrology. This was also evident in the medical field. Every part of the body relates to a zodiac sign/ Sun sign and predisposition related to that body part i.e Virgo relates to nerves and matters of the intestines and Capricorns usually have skin, bones or joints such as knees complaints.
Can you discern from the image that Aries relates to the head (i.e. often a marking or scar on the head), Taurus the neck area (i.e. thyroid), Gemini the arms and shoulders, Cancer the chest, and breasts, Leo the heart, Virgo the intestines, Libra the kidneys generally, Scorpio the reproductive organs, Sagittarius the hips and thighs, Capricorn the knees, Aquarius the ankles and finally Pisces, the feet.
This image of the Zodiac Child (received from a client) was on display in Padova, near Venice recently (Italy being rich in astrological art). Doctors used to consult similar images (body of knowledge) according to the symptoms a client showed, as well as before commencing any treatment. Medical astrology is still practised but by certified medical practitioners. Monica Cromhout posted this interesting article by Michael Waters recently and it pertains to this very concept https://www.atlasobscura.com/articles/zodiac-man-astrology-ketham