Much like a finger leaves its own unique print to help identify someone, skull fractures may leave telltale signs that can help investigators better determine what caused an injury.
The findings could help uncover what really happened in child abuse cases, potentially resulting in very different outcomes, researchers say.
Until now, researchers believed that multiple skull fractures meant several points of impact to the head that were often classified as child abuse.
The new research proves that theory false: a single blow to the head not only causes one fracture, but may also cause several, unconnected fractures in the skull. Additionally, not all fractures start at the point of impact—some actually may begin in a remote location and travel back toward the impact site.
“It’s a bit like smashing raw hamburger into a patty on the grill,” says Roger Haut, professor of biomechanics at Michigan State University. “When you press down on the meat to flatten it, all the edges crack. That’s what can happen when a head injury occurs.”
Because piglet skulls have similar mechanical properties as infant human skulls—meaning they bend and break in similar ways—researchers used already deceased pig specimens in their research. They were able to classify the different fracture patterns with a high degree of accuracy.
“Our impact scenarios on the piglet skulls gave us about an 82 percent accuracy rate, while on the older skulls, it improved to about 95 percent,” says forensic anthropologist Todd Fenton.
To help them get to this level of accuracy, the researchers teamed up with Anil Jain, professor of computer science and engineering, to develop a mathematical algorithm to help classify the fractures.
“A major issue in child death cases is you never really know what happened,” Haut says. “The prosecutor may have one idea, the medical examiner another, and the defendant a completely different scenario.”
Fenton and Haut’s have used the new findings to help solve hard-to-determine child abuse cases—and now are also looking to use Jain’s algorithm in an online resource that will provide even more assistance to investigators.
A database called Fracture Printing Interface is under development and will allow forensic anthropologists and investigators to upload human fracture patterns from different abuse cases to determine what most likely caused an injury.
“We will never know with 100 percent probability what happened in many of these cases, but this interface will give us a higher chance of figuring that out,” Haut says.
The researchers presented the findings at the annual meeting of the American Academy of Forensic Sciences. The National Institute of Justice funded the work.
Source: Michigan State University