The heavens on the AS ABOVE is the macrocosm, and we humans on the SO BELOW, the microcosm. Humans are made of the heavens who are found among the stars and planets. The microcosm is oneself, and the macrocosm is the universe.
This famous middle age illustration below is of the "zodiac man." It is a 1500 printing of Joannes de Ketham's Fasciculus Medicinae and is thought to be the first medical textbook in the era of print.
The text surrounding zodiac man is to help direct physicians about the proper dating and timing for certain medical treatments. For example, treating maladies of the head would be very dangerous when the sun is in Aries because of the sign's anatomical association.