It's controversial as to who actually made the first successful facial reconstruction, but it's often credited to the German anatomist, W. His, who published the results of his studies in 1895. He had acquired a skull said to be that of the late composer Johann Sebastian Bach, and from it, he sculpted what turned out to be a very good facial likeness.
To find out the general depth of the skin and muscles over the skull, His had plunged oiled needles into the faces of corpses. At the top of each needle, he attached a cork. Once the needle hit bone, the cork rested at the skin's surface. He then pulled the needles out, measured them and made drawings based on the measurements. That way he managed to compose a depth map, which would aid anthropologists of succeeding generations in making portraits from skulls. (Modern researches now use ultrasound, not corpses, for tissue-depth studies.)
Another sculpture was made by a police anatomist in 1916 when a skeleton was recovered in Brooklyn. He placed the skull on some rolled newspaper, put some fake eyes into the sockets, and covered the bones with flesh-colored plastic. A sculptor added sufficient details for the accurate identification of a missing woman.
It was in Russia, however, where the technique of forensic sculpture was more fully developed. Mikhail Gerasimov headed the department of archaeology at a museum and he experimented with the skulls in his care. By 1935, he had become fairly adept at taking a skull and reforming it into a face that people recognized. Four years later, he helped to solve a murder. In 1950, the USSR established the Laboratory for Plastic Reconstruction, and for years they were the renowned experts in the field.
Perhaps the most famous sculpture was the one that American sculptor Frank Bender did of the missing John List. In 1971 in New Jersey, List had murdered his wife, three children, and aged mother, and then fled. Detectives on the case failed again and again to find productive leads. They did some photographic enhancements to try to replicate a likeness of how List might have aged, but it was the sculpture that Bender did that finally turned the tide. For a television show, America's Most Wanted, he created a three-dimensional face based on a number of factors that helped him to imagine what List would look like in 1989—almost two decades after the murders. When this was shown on TV, a former neighbor of "Bob Clark" in Colorado called in what she knew. Through fingerprints, Clark was identified as List, and he was charged and convicted.
Briefly, the technique involves first making a cast of the skull (or sometimes using the skull itself). Where there's no skull, the artist must rely on computer-enhanced photos to replicate a skull clay bust. Using the skull or replica, small holes are made for thin wooden or vinyl pegs to be inserted for measuring the skin depth. Then modeling clay fills in the muscles and features around the nose, mouth, cheeks, and eyes, and a thin layer of plastic or clay goes over the skull. Facial features are molded to capture the person's basic look, and a wig and artificial eyes are added, along with make-up similar to what an embalmer might use for cosmetic enhancement.
Another technique is to set the skull on a turntable. As it turns, information is fed into a computer via a laser beam and assembled into a likeness, based on information from other faces with similar measurements and racial origins.
One place that does this work is the FACES lab at Louisiana State University, run by the Bone Lady. Let's see how she handled one of her cases.