Jerrel Catlett’s eyes narrowed on the large intestine, a gloppy, glow stick-like object whose color matched the stool stored inside of it. He chose to isolate the organ, and it expanded on his screen as the body parts surrounding it receded — the gall bladder bright green with bile, the ribs white and curved like half moons.

“My old boss used to tell me that when I did this, I’d be so wowed by how complex the human body is,” said Mr. Catlett, 25, a first-year student at Icahn School of Medicine at Mount Sinai, gesturing to the image of a body on his laptop screen. “But it feels like there’s something missing from the experience right now.”

For generations, medical students were initiated to their training by a ritual as gory as it was awe-inducing: the cadaver dissection. Since at least the 14th century, physicians have honed their understanding of human anatomy by examining dead bodies. But amid the coronavirus pandemic, the cadaver dissection — like many hands-on aspects of the medical curriculum — turned virtual, using a three-dimensional simulation software.

Of the country’s 155 medical schools, a majority transitioned at least part of their first and second-year curriculums to remote learning during the pandemic. Nearly three-quarters offered lectures virtually, according to a survey by the Association of American Medical Colleges, and 40 percent used virtual platforms to teach students how to interview patients about their symptoms and take their medical histories. Though the cadaver dissection posed a trickier challenge, nearly 30 percent of medical schools, including Mount Sinai, used online platforms to teach anatomy.