January 21, 2012 | 1
RALEIGH, N.C.—Bone-hunters and anthropologists typically guard their fossils as priceless specimens. I’ve learned to ask: “Is that real or a cast?” when shown a specimen. Often it’s a replica. So, I was as thrilled as a 12-year-old today when I saw two real, contemporary human skeletons and several human skulls during a tour here of forensic anthropologist Ann Ross’s Osteology Lab in the Park Shops building at North Carolina State University (NCSU). (See Anna Kuchment’s longer article on this lab in the September 2010 issue of Scientific American, as well as this slide show and video that reveals other comparisons made by forensic anthropologists.) I admit to taking a ghoulish but also scientifically curious delight in learning about forensic science, and I’m clearly not alone given all the TV crime shows that trade on such details.
The focus in Ross’s lab, however, is as serious as murder. Anthropologists, entomologists and other experts at NCSU tackle about a dozen complicated cases a year referred to the Osteology Lab by the state medical examiner—typically dismemberment or child abuse cases. Ross’s lab will conduct analyses to determine the tool used by a criminal to cut apart bones. In fact, she casually pointed to several sawed-up pig bones set out on a lab bench. Their job: to help analysts determine whether a hand saw or powered saw was used in a recent human dismemberment case.
In Ross’s wet lab, tissue is removed from bones by boiling them in water for 30 minutes, or letting borax, bleach or laundry detergent go to work on them. Ross had set out a disarticulated skeleton on an exam table to show a group of us from the ScienceOnline2012 conference. Holding up a femur, then the skull, a radius and the pelvic girdle, she showed us some of the features used to identify corpses and determine the probable cause of death—worn-down processes, muscle markings, a retreating chin. DNA, radiographic, morphometric and dental data also contribute, when available. In this case, two bullet holes through the skull and an exit blast made the cause of death clear. Patterns of radiating fractures in the skull revealed which bullet struck first and gave clues about the caliber of the firearm used. Skull bone suture patterns accumulated over the first couple of decades of the victim’s life revealed clues to his ancestry—MesoAmerican. Missing teeth indicated poor nutrition.
Forensic anthropology has also been put to systematic use by Ross to help identify risk factors for genocide. Her studies have shown that genocide victims typically suffer from such conditions as poor nutrition, spina bifida, middle-ear infections and severe dental enamel defects. Preventive policy could be implemented in areas where a high presence of these factors confirms other social data to suggest an increased probability for regional genocide. She has conducted such analyses on bodies collected in Rwanda, Bosnia and Croatia.
Ross stresses that her role as a forensic anthropologist is to present the facts as clearly and as objectively as possible. “I sit up nights and think about a case—did I miss something?” she said. Her goal is to “bring resolution to someone who had no voice,” to people, often children, whose cases fell through the cracks of the criminal justice system.
Image caption: Case of human skulls in NCSU forensic anthropologist Ann Ross’s Osteology Lab. Can you tell which one is not a cast/replica? Credit: Robin Lloyd