21. Medieval medicine included the practice of astrology
The signs of the zodiac were a major influence on medieval medicine, in all its forms, including folk medicine, pagan beliefs, and the education of physicians in formal schools. The signs of the zodiac were displayed in medical texts throughout the medieval world, corresponding to both the humors believed to be the basis of health and the parts of the body. The planets and other celestial bodies were also associated with parts of the body, with the sun associated with the heart; Mars with the arteries (as well as the nails and hair); Venus with the kidneys and digestion, and so on. Their influence was reflected in many ways, including the scheduling of treatments and surgeries, the planting and harvesting of medicinal plants, the manufacturing of medicines, and the administration of them.
The signs of the zodiac influenced a physician’s diagnosis, based on which sign the moon was in when symptoms first occurred. Aries (the first sign of the zodiac calendar) corresponded to the head and face; Pisces (the last) to the feet, with the rest of the signs corresponding to parts of the body in between. A physician noting the moon was in Gemini when a patient developed coughing symptoms would be likely to diagnose an illness of the lungs, though a moon in Taurus could direct him to consider a problem of the throat. Diagnosis was not based on astrology alone, but it was a major consideration for physicians when evaluating their patients throughout the medieval period.