It was the red toenail polish that left one first-year medical student at the University of Colorado breathless—the ineffable reminder that the cadaver he dissected in anatomy lab was once a living person with family, friends, and a tender touch of vanity.

Anatomy, the study of the architecture of the human body, is by tradition the defining course of a doctor’s training. The rite of passage—accompanied by anxiety, fear, and, sometimes, nausea—is “for many, the first encounter with a dead body,” Frank Herlong, a former associate dean for student affairs at the Johns Hopkins School of Medicine, once said.

But anatomical dissection, like much else, is shifting to digital. (See “The Immortal Corpse,” in the January 2019 issue of National Geographic.)