Doctors Gilson Barreto and Marcelo de Oliveira say that 34 of the 38 panels of the frescos contain encoded anatomical diagrams, with trees looking like bronchial tubes, a green bag looking like a human heart, and other subtleties.
Although the new claims are as yet unproven, other researchers have made similar observations in the past. More than a decade ago, Dr. Frank Meshberger pointed out that a gathering of God and angels in "Creation of Adam" bears a striking resemblance to a diagram of a human brain in cross section. Meshberger's theory is that the artist was equating the gift of intelligence with the divine spark of life.
Other experts say Barreto and Marcelo may be "seeing what they want to see" in Michaelangelo's work, or that perhaps he used anatomical shapes as a convenient model of natural ordering, with no deeper meaning intended.
Commentary is being sought from other historians and the Vatican.