Whenever we find remains, the most important thing is to know who it is. We can do many and very detailed analyzes on the findings in that body, especially in skeletal trauma, but if we do not know who it is, that information is of no use to us.
The age of the corpse is part of what we call the biological profile; It is technically an estimate of sex, ancestry, age and height. This general description of the individual helps the police authorities with whom you are working to search, in the list of missing persons, for someone who matches those general characteristics of the corpse. What you tell them is: these remains correspond to a man or woman, in this age range, who measured approximately this height range and who was very likely African American, Asian, Caucasian, etc. With this data they can search for candidates for this identity on the missing persons list. Generally, after this search they give us a list of people who match the description and we make a comparison between the data ante mortem and postmortem and so we know if it is one of them.
What I always tell my students is that, of the four data that make up the biological profile of a corpse, it is often not possible to estimate the ancestor by skeletal methods and height is not a data that provides much information, which is why Sex and age are the most important thing. They are the basis of the biological profile.
To answer your question, I will tell you that when you receive some remains, the first thing you do is look at them from a bird’s eye view. Once they are processed (cleaned) we put them in anatomical position and look at them to know what type of case we have before us. This first view already tells us if it is a juvenile or adult individual (due to the size and fusion of the bones), if it was a young adult or an elderly adult (due to the degenerative changes in the bones), if it was man or woman (due to the morphology of the pelvis and skull). After this we apply different methods to refine the estimates.
When we are born we have about 806 or 807 ossification centers, that is, bone fragments. These bone fragments fuse and we end up with 206 or 207 bones in adulthood. There are some structures that fuse earlier than others, so those that fuse later are the ones that help us fine-tune the age. For example, if everything is just merging, it helps us know if the individual is between approximately 18 and 25 years old. And after this, in adults, a progressive degeneration of the skeleton will occur.
If it is a juvenile individual, we rely on growth and development, which is the most accurate to make an age estimate. When it comes to the remains of an adult we have no choice but to look at the signs of skeletal degeneration. And in both cases we use bones and teeth. In juvenile individuals, the most accurate thing is the development of the teeth because until around ten years old you can ignore all environmental factors, since they have almost no influence.
When it comes to the remains of an adult individual, things get complicated because there are many environmental factors that greatly influence the way we age: diet, toxic substance abuse, exercise, etc. This means that when we estimate the age of a juvenile, we may have a range of three or four years in the range for the estimate, on the other hand, for an adult it is decades.
Something important to highlight in the answer to your question is that age estimates are never an exact number, if they give you an age of a corpse in an exact number, don’t believe it. An age estimate is given as the age you calculated plus/minus any possible error in the method you used.
Nowadays, differentiating a 70 or 80 year old person from a 100 year old person is a problem. We do not have many means to distinguish older adults, there are no methods that allow you to distinguish if someone is 60 or 100 years old. And I think more research is needed in this regard.
Joe Adserias-Garriga is an anthropologist and forensic odontologist at Mercyhurst University (Pennsylvania, United States).
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