When scientists are working with only partial remains, it can be very difficult to determine age. Now forensic anthropologists say they've found a way to help approximate age in children: noninvasive X-rays of the skull's frontal sinus region. Reporting in the journal Anatomical Record, they say that's because the human sinus develops in a fairly regular and predictable way, with four different stages suggesting different ages. "This approach should be particularly valuable when working with incomplete remains," one North Carolina State University researcher says. But it's not an exact measurement because the development of the sinus only suggests age ranges.
Stage 0, when the frontal sinus isn't even detectable, is found in kids younger than 6, the researchers found. Stage 1, when two small cavities appear with a gap between them, goes from ages 6 to 8; Stage 2, when those cavities get larger and touch, begins between ages 7 and 10; and Stage 3, when the two cavities merge, happens between ages 12 and 18. Researchers say the technique could also be used to approximate the age of living children who don't have an official birth record, but acknowledge their technique "would be even more valuable if we could improve its specificity." Indeed, their paper notes that for now, "the age ranges can be quite wide and should be utilized alongside other established methods of age estimation." (It's still hard for forensic scientists to determine time of death.)