anatomy, always connected to their neighboring bones just as nature intended. As a forensic anthropologist, I would not always have the luxury of whole bones. A murderer might deliberately shatter his victims' bones, or a dog, bear, or coyote might crunch the bones between its teeth. And fire could reduce a human skeleton to mere fragments with devastating efficiency.
As a result, Dr. Bass insisted that we be able to instantly identify small fragments of bone, as well as the whole bones that are standard fare in most anatomy and anthropology classes. This seemed like a daunting challenge at first, but we soon learned that all bones have identifying features that make them unique, distinguishing each bone from every other and even separating right from left. For example, the metacarpals-the bones extending from the palm of the hand-all look alike at first glance, but if you look at the end that joins the wrist bones, you can see that each has a slightly different shape.
Once we'd learned the secrets of each individual bone, we had to be able to look at a fragment and pick out the one feature that would help us identify it. The mandibular condyle, for instance, is a tiny part of the jawbone that fits into the corresponding groove of the skull-no bigger than a plump raisin. It has a shape that is unlike any other piece of the human skeleton, and once its image is firmly anchored in your mind, you can not only recognize it, you can tell which side of the jaw it comes from, even if the rest of the jaw is missing.
As soon as we started to feel the first glimmer of confidence in our ability to identify adult skeletal material, we had to step back in time and learn how these bones looked while they were still growing. The bones of newborns and infants were a wonder to behold, but the differences in shape and size from adult bones added yet another element of confusion. Soon I learned, though, that even the tiniest bones had a distinctive shape that resembled at least a portion of their adult counterparts.
The skull is incredibly difficult to understand in its infant form, and even adult skulls are tough to deal with when they're fragmented. Almost everyone can recognize the familiar shape of a complete human skull, but together the cranium and the face contain over two dozen separate components. Big, relatively flat bones form the back, top, and sides of the skull, with smaller, more complex bones surrounding the eyes and face. In decomposed or skeletonized infants, these bones are thin, incompletely formed, and not connected at all, looking more like big, irregular restaurant- style corn chips than human bones. Again, Dr. Bass insisted that we know skull fragments backward and forward. He knew, and we were soon to learn, that the skull is a favorite target of murderers.
I must admit, it took me a while to hit my stride in osteology class-the way an anthropologist looks at bones is simply so different from the way an orthopedic surgeon views them. I was used to seeing bones live and whole, within a huge organic structure of which they were only a small though vital part-not as isolated elements that might be found scattered in a field or piled in the corner of a basement.
But once we moved from whole-bone identification to the analysis of fragments, my competitive spirit came through. My friend and fellow student, Tyler O'Brien, would sneak into the osteology lab with me each night, and we spent hours quizzing each other on every fragment in the collection. First we learned by sight-“Half of a right patella.” “Portion of a lumbar vertebra.” Then we shut our eyes and set ourselves to learning by touch alone the unique characteristics of each bone.
That process had taken months-but it had served us well. Both of us, as well as most of the class, could now take the merest glance at a whole bone and tell you what it was and which side of the body it came from. We could pick up the smallest fragment and find the key to its identity. Solving these intricate three-dimensional puzzles became a new and thrilling game.
Soon we were ready for an even more fascinating task-applying this knowledge to forensic anthropology analyses. Now, though, it was no longer a game. We were being taught to practice on real cases-albeit cases that had been solved years before. But our subjects were real people who had died violent deaths. It was up to us to figure out who they were and what had happened to them.
The routine was always the same. Dr. Bass would bring a collection of bones into the classroom on Tuesday morning, along with any pertinent case information, and leave everything there for a week. A skull, mandible, two thigh bones, and a section of pelvis might be piled on top of a tray along with the preliminary notes taken on the day the bones were found-for example, “Human skeletal remains found in a ditch along Alcoa Highway on July 7, 1987. No clothing was recovered.” Then we had to analyze the remains, explaining what they told us about the victim's age, race, sex, stature, and any other clues we could come up with.
There were only about fifteen students in our class, so we split into teams of three or four and took turns examining the bones during the week and in our Thursday class. By the following Tuesday, we were each expected to produce a report-just like the ones we might turn in to a police investigation-telling the investigators everything we'd gleaned from our anthropologic examination. In fact, the class was as much about preparing the report as it was about analyzing the remains-no forensic anthropologist will last very long if he or she can't document evidence and share information with investigators-and it was made crystal clear from the beginning that we were to choose our words carefully and back up our opinions with good, hard science.
I was used to writing reports, of course, but only in the style of the medical records I had worked with at the clinic, in which a typical entry might state confidently, “This is a forty-five-year-old White female, 5'6'' tall weighing 145 pounds.” Of course, you could describe a whole body-living or dead-in that kind of detail. When all you've got is a skeleton, you can never be that specific, though you can usually come up with a more basic biological profile. For example:
BIOLOGICAL PROFILE: Case # 02-17
Every biological profile, Dr. Bass told us, would ideally include the anthropologist's “Big Four”: sex, age, race, and stature. If you're lucky, and you've got the evidence to go further, you can put in ancillary information such as weight and maybe hair color. Often, human remains
Sometimes the associated evidence-evidence found with a body or remains-can give you a clue. Clothing, for example, can help you determine a person's weight and size, though, of course, it too tends to decompose. In the end, though, the bones last longest-and they hold many secrets if you know what to look for.
One of the most basic ways we identify each other is by sex, so when I'm looking at newly discovered bones, I often start by asking myself whether they belonged to a man or a woman. Under these circumstances, I hope I've got at least part of the skull or the pelvis, because these bones possess the best morphological features to reveal the differences between male and female. (“Morphology” means the logic of shapes, the characteristics of a structure that can be seen but are difficult to measure.) Males, for instance, usually have a line of bone that juts out to form the “brow ridge,” a horizontal ridge between their forehead and the tops of their eye sockets. This ridge is smaller, or absent entirely, in females. Males also have distinctive areas-much bigger than women's-for their large muscles to attach behind each ear and in the back of the head, near the hairline.
But it's the pelvis that really tells you about someone's sex. The pelvis is made up of three separate bones. At the bottom of the spine sits the sacrum, a wide, thick bone, shaped like a slice of pie and full of holes. On either side sits the “innominate” or “no-name” bones, two relatively flat, softly curved slabs, each with a socket for one of the hip joints and a notch that allows the sciatic nerve to pass from the spine down into the leg. In females this sciatic notch begins to spread widely as a girl matures, while the front and back of a girl's pelvis becomes wider to accommodate the possible birth of a child. In men, the sciatic notch is narrower, as is the entire pelvis.
Overall, male skeletons tend to be larger and more robust than those of females, but there are exceptions to every rule. We've all met plenty of robust females and small, gracile males.
If sex is tricky to determine, age is really tough. After all, there are only two sexes-but a skeleton might be any age from 0 to 100. I personally have enough trouble telling the age of a living person, even when I can look at indicators like posture, hair color, and wrinkles.
Because exact age is so hard to figure, a forensic report usually gives age as an estimated range-say, thirty to forty in an adult; twelve to fifteen in a teenager or “subadult.” Subadults' ages are easier to estimate, since their bones and teeth mature at a pretty steady and well-documented rate for the first fifteen or sixteen years. Then their bones undergo changes that are a little less predictable as they enter their early twenties. The bones usually don't get any bigger after that, but they do continue to mature until the middle to late twenties.
Age-related changes continue until the day we die, showing up in our ribs, pelvis, and weight-bearing joints-knees, hips, ankles, and spine. The ends of our ribs are stressed every time we take a breath, while the bones of our pelvis grate together throughout our entire lives. The amount of movement is usually so minuscule that we don't even notice it-yet over time that movement is enough to wear down the underlying bone in ways that an anthropologist can use to read a person's age.
Likewise, although the joining, or articulating, bones in the ankles, knees, hips, and spine are covered with a generous cushion of cartilage, sooner or later the cartilage wears down, leaving a record of every day we've stood upright and all the thousands of miles we've walked. And as the cartilage wears down, like the rubber on a tire, the underlying bone begins to show changes: first some irregularities around the edge of the joint, then some roughening of the gliding surfaces. With extreme age-related changes, the whole joint can appear to bubble and boil with bony convolutions, and the weight-bearing surfaces might even collapse.
Age-related changes aren't limited to the legs or spine. The arms, hands, and shoulders are also susceptible to disease and can also show lifelong signs of wear and tear. And then there are the teeth: Are they rugged and unstained? Well worn? Missing, with subsequent absorption of bone?
You'd think estimating a person's stature, or height, would be easiest of all, and you'd be right-if you had a complete body or the right bones. If all you've got is, say, a rib, you're out of luck. Stature can best be calculated from the leg bones, though the arm bones come in a good close second. The length of any of these bones can be entered into a mathematical formula which can then be used to calculate the stature of an individual within a limited range.
Finally, we come to race, a subject that can quickly become touchy and politically charged. For forensic anthropologists, though, race is less of a political topic than a matter of procedure: What can we find out about a mass of bones or body parts that will help police figure out who the person was? In our society, people tend to identify themselves by race, and their friends, family, and coworkers usually know them that way, too. So Dr. Bass made sure we knew the latest thinking on how skeletal structure might vary, depending on a person's racial background.
The bones of a person's mid-face-eye sockets, cheeks, nose, and mouth-reveal our ethnic heritage. For example, Negroid heritage is displayed in a skull with a wide, flattened opening for the nose, wide-set eye sockets, and a forward projecting set of upper and lower jaws. Likewise, a long, narrow nose with a high-pitched nasal bridge and oval-shaped eye orbits tells me that the skull probably belonged to a Caucasian, while in someone of Asian parentage, I would expect to see relatively flat cheekbones and a nose whose characteristics fall somewhere between Negroids and Caucasians-neither flat nor high-bridged.
To learn all of this had taken us months-but by the time Dr. Bass threw his latest challenge at us, we'd all gotten pretty good and he knew it. Yet as he'd given us this week's collection of bones, his words had had the ring of triumph: “In twenty years, no one has ever gotten this one right.” Why not? It seemed to me that every one of us could have measured the bones on the tray, identified the morphological traits, and then told him that we were looking at a tall, well-muscled White man in his sixties. Why would such a simple problem have stumped students for the past two decades?
It was Friday night before I found my way back to the lab where Tyler and I worked together, measuring each bone and documenting our findings. We'd learned through the grapevine that our conclusions didn't differ from anyone else's. Yet I just couldn't shake the feeling that I was missing something.
The night before my report was due, I returned yet again to the lab. I ran my fingers over the contours of the bones and stared at them for hours in the semi-trancelike stillness that was often where I got my best ideas.
And then, suddenly, I
The next day, Dr. Bass collected our reports and began his usual oral questioning. “How many think this skeleton was male?”
Every hand in the room went up.
“Middle-aged?”
