“Then study,” I snapped. She dropped the class three days later, but not before turning in a quiz on the bones of the hand and arm, in which she defined humerus as “something that, like, makes you laugh.”
Today’s class — like the day of the migrating miniskirt — also happened to focus on pelvic structure. That seemed fitting, since I’d just been examining the pelvis of the body — the woman — found in the cave in Cooke County. As a teaching aid, I’d brought to class two sets of pelvic bones, one male and the other female, from the skeletal collection I’d been building over the years. Using red dental wax as a temporary adhesive, I reattached the pubic bones to the innominates, or hip bones, and then held them up, first the male, then the female. “Okay, I’ve noticed some of you carefully studying the pelvises of your classmates. So I’m sure you’ll have no trouble identifying the differences between the male and female.”
A laugh rippled across the room — a good beginning. “Which is the female, number one or number two?”
“Number two,” chorused a handful of voices.
“Very good. How can you tell?”
“It’s wider,” chirped one girl.
“Cuter, too,” added a boy.
“The bones in front come out farther,” said someone.
“That’s right, the pubic bones project more,” I said. “Why is that?”
“Pregnancy?”
“Right, to make room for the baby,” I said, “not just during pregnancy, but also — especially — during childbirth.” I rotated the pelvis backward by 90 degrees, giving them an obstetrician’s-eye view of the bones that frame the birth canal. “You see the size of that opening? That’s what a baby’s head has to fit through during childbirth. Now compare it to the male’s.” I held up the narrower pelvis in the same position. “Any of you fellows think you could pop a baby out through there? You better hope you never have to try!” I heard a few murmurs along the lines of “Ouch, man.”
Next I showed them the female’s sciatic notch — the notch just behind the hip joint where the sciatic nerve emerges from the spinal column and runs down the leg. “See any difference here?”
“Wider.” “Bigger.”
“Correct. That’s another result of the geometry of childbearing: as the female’s innominates flare out at puberty, this notch gets wider. Notice that I can easily fit two fingers into the base of this notch, but only one in the sciatic notch of the male? So ten years from now, when you’re working a forensic case, and a hunter or a police officer brings you nothing but a single innominate bone, you can tell immediately whether it came from a man or a woman.”
One of the girls near the front — Sarah Carmichael, according to the seating chart; she wore sensible clothes and asked sensible questions — said, “But if those changes don’t happen until puberty, how can you tell the sex of a child’s skeleton?”
“Good question, Miss Carmichael. The answer is, you can’t. Before puberty, there’s no reliable way to distinguish between the bones of males and those of females. All you can do is tell whether the bones you have are the right size for a boy or a girl of a given age.”
Most of them looked puzzled, so I trotted out an example. “When I looked at the child’s bones that were recovered in the Lindbergh kidnapping case”—a few heads nodded, but there were blank looks on a lot of faces—“I couldn’t say for certain whether they were the bones of a boy or a girl. All I could say was that they were consistent with the bones of a twenty-month-old male — which is how old Charles Lindbergh Junior was at the time he was kidnapped and killed. But the bones would also have been consistent with a twenty-four-month-old female.”
Sarah raised her hand again. “In that case, couldn’t you do a DNA test on the bones and compare it to the parents?” Sarah’s quickness and interest actually made her far more appealing than any temptress in a slithering skirt.
“You couldn’t back then, of course — the crime occurred about sixty years before DNA testing became common — but you could now,” I said. “The bones have been kept in glass vials; there’s even a little bit of soft tissue on some of them still, so there’s probably plenty of DNA for a test. But the authorities and the Lindbergh family seem confident of the identification: the clothing matched what the boy was wearing, and one of the feet had crossed toes, a genetic anomaly that was pretty distinctive. So there’s really no good reason to put the family through more anxiety this long after the case has been closed.” Sarah nodded thoughtfully.
“Let’s get back to the pelvis,” I said. “I’m going to pass these around. Be careful. I know most of you fellows have never handled a female pelvis before, so this is a good time to practice a gentle touch.” That was an old joke; it used to get laughs throughout the room, but something had shifted over the past few years, I’d noticed. The boys would still laugh, but the girls tended to frown now instead. I made a mental note to drop that line from the lecture next year.
As the pelvises made the rounds of the class, I explained how the face of the pubic symphysis — the joint where the two pubic bones meet at the midline of the abdomen — changes with age, and how those changes could reveal a person’s age at death. I passed around two additional pubic bones — one from an eighteen-year-old female, the other from a forty-four-year-old — so they could see for themselves the erosion that occurs during a quarter-century of wear and tear.
As the female pelvis reached Sarah, I noticed her rotating it, scrutinizing it from every angle. She furrowed her brow and chewed on her lower lip, concentrating intently. I walked toward her row. “Did you have another question?”
She looked up. “Can you tell just from the bones whether this female — whether any female — has given birth?”
It was a simple, logical, and innocent question, and it blindsided me completely. Visions of Kathleen — in the throes of labor, and then in the throes of death — writhed in my head, mingling with images of the strangled young woman and her sad little fetus. After what could have been either half a minute or half an hour, I became aware of the students’ stares.
“Yes,” I finally murmured. “Yes. You can.”
I stumbled toward the door.
“Class dismissed.”
CHAPTER 10
By the time I threaded my way back to the hallway beneath the stadium, my runaway pulse had slowed to a trot and the ragged edge had left my breathing.
The hallways in the Anthropology Department echo the shape of the stadium above, so where the stands wrap around the end zones, the hallways bend as well. Walking along a dim, curving tunnel that continuously unspools ahead, you get the sensation that you’re in some miraculously preserved Minoan labyrinth or some prodigiously dilapidated space station. As I banked toward my office, Deputy Leon Williams came into view, studying a posterboard presentation on nineteenth-century Navajo skulls.