Plastic Copies of ‘Iceman’ Skull Will Teach Scientists Plenty About the Distant Past : Anthropology: Process should help recreate what the doomed man’s face looked like before he was swallowed up by an alpine glacier 5,000 years ago.

More than 5,000 years ago, he lay down in the Tyrolean Alps and died. Three years ago, his frozen and exquisitely preserved body emerged from a glacier and made worldwide headlines.

Now, scientists report they have used X-rays and modern technology to create highly accurate replicas of the skull of the “iceman.”

The accomplishment should help scientists study the iceman and recreate what the doomed man’s face looked like when he was alive, the researchers say.

The replicas should reveal for the first time just how the iceman’s facial bones were slowly distorted by eons of pressure from the glacial ice, said team member Horst Seidler of the University of Vienna.

In prior X-ray studies of the skull, “no one saw (that) the iceman’s skull is truly deformed,” Seidler said. With the help of the copies, researchers now can reconstruct “a nearly true face,” he said.

One analysis has revealed that the part of the iceman’s face between his upper teeth and the top of his nose was pressed toward the rear of his head, for example. That misled Seidler and colleagues in their earlier interpretation of how the upper teeth originally met the lower teeth.

The iceman, covered with leathery orange-brown skin, is now kept frozen at high humidity to mimic the glacial conditions that preserved his body so well. Researchers who want to examine him are limited to about 20 minutes every two weeks.

Austrian researchers decided to make copies of the skull so that scientists could study details of it at leisure without disturbing the iceman, said radiologist Dr. Dietzer zur Nedden of the University of Innsbruck.

“It’s impossible to take all the measurements. It’s impossible to see inside the mummy because you can’t destroy it,” he said.

He and colleagues reported their work in the October issue of the journal Radiology. They used a technique called stereolithography, which is used at a few medical centers to make models of body parts. The body-part models are useful for building hip replacements or planning complex surgery to fix misshapen skulls.

To copy the iceman’s skull, researchers removed the iceman from his freezer to an examination room kept at about 45 degrees Fahrenheit. Then, they scanned his head with an X-ray technique called computed tomography, which allowed a computer to store electronic “slices” of the skull.

A second computer used this information to build skull replicas slice by slice, using a laser beam to shape plastic. The copies reveal not only the exterior of the skull, but its interior shape and bones.

Dean Falk of the State University of New York at Albany, an anthropologist who studies skulls for research on brain evolution, called the work “cutting edge” and “really first rate.”

Scientists have made three skull copies so far, each better than the last, and hope to reproduce the entire iceman skeleton, Zur Nedden said.

The researchers also have made what Seidler said is the first plastic reconstruction of a fossil skull, copying a specimen 300,000 to 400,000 years old from Petralona in northern Greece.

Unlike the original skull, the copy can be cut open to give scientists a detailed look at the interior, including the impressions made by the brain, he said.

Noting that the work on the Petralona skull replica was done with experience gained on the iceman, Seidler described it as “a present of the iceman to us.”