‘Bone-ified’ Professors of Anatomy

November 2016—Standing in front of a third-grade classroom, a teacher asks, “Who was the first president of the United States?” Instantly, there’s a room full of eager hands, waving and trembling with the demand “Pick me! Pick me!”

It’s a familiar scene for all of us, but last month it took on new meaning for me. I was again in a classroom, this one for first-year medical students studying anatomy. The professor at the helm that morning was describing the precise shape and rotational capacity of the shoulder joint, the attachment points for its ligaments and tendons, the names of different muscles. Then, he told us that raising the hand directly above the shoulder is a skill we share only with our closest relatives, the apes, who still use it for swinging from trees. 

Suddenly, what had been a laundry list of information became a story, just one of many stitched together by the evolutionary biologists of the Center for Functional Anatomy and Evolution as they initiate a new crop of students to medical school at Johns Hopkins.

It’s Class Time

Every year, on a Monday morning in mid-August, the west auditorium in the Anne and Mike Armstrong Medical Education building fills with a new class of enthusiastic medical students. They are about to embark on an intensive class in human anatomy. It is so time-consuming, they will take only one other class for most of the next seven weeks. An hour of lecture each day precedes four hours of hands-on work, usually dissecting cadavers but sometimes working on sophisticated “dummies” in the simulation center or doing team-based learning exercises. 

“The students have a limited amount of time to accomplish a lot. They really have to concentrate,” says evolutionary biologist Christopher Ruff, the shoulder expert and director of the course. “It’s nice to see them gaining confidence as time goes on.”

Bone Experts

Most of the year, Ruff is not teaching anatomy to med students. He’s more likely to be studying fossilized bones in his lab or at a museum abroad. He wants to understand what skeletons can tell us — about the evolution of nonhuman and human primates, and about their daily lives.

“When humans in Europe moved from agriculture to city living, their bones adapted, just like when apes started standing upright,” says Ruff. “I look at everything from African fossils millions of years old, like Lucy, to more recent human skeletons from Europe and North America and ask, how did we get to be the way we are now?”

Anatomy is taught primarily by Ruff and five other evolutionary biologists — the entire faculty of the Center for Functional Anatomy and Evolution — but there are also eight sessions taught by medical doctors to supplement the main lectures with clinical details, like the most common patient complaints for a given body part.

Lisa Zhang, a current first-year student, likes the balance. “The medical doctors tell us, ‘Avoid that nerve [during surgery]!’ The biologists tell us why that nerve is there in the first place and what it does.” 

Comparative Anatomy

One nonhuman animal you might “meet” in Perry’s anatomy class is an aye-aye. Aye-ayes are small, nocturnal primates whose ears are specialized to detect wriggling grubs in rotting wood. Credit: iStock

Another student , Aneesha Cheedalla, says the biologists love to stray from human anatomy from time to time to discuss interesting features of other animals, like sea otters.

“When Dr. [Siobhan] Cooke was giving her lecture on the jaw, she showed a sea otter’s jaw next to a human jaw. Then, she explained the differences and how those differences provide advantages and disadvantages. That really helped me remember the features of the human jaw,” says Cheedalla.

Jonathan Perry, who researches chewing in primates, says those nonhuman factoids aren’t in lecture handouts or on tests, but he and his colleagues enjoy sneaking them in to liven up their lectures and provide evolutionary context.

Jonathan Perry feeds cantaloupe to a red ruffed lemur (Varencia rubra) at the Duke Lemur Center, N.C. Credit: Jonathan Perry

Sometimes that evolutionary context also provides students with the “why” behind our current anatomy. For example, when teaching about the ear, Perry mentioned that fish don’t have a middle ear cavity. That’s because the middle ear “translates” sound waves from the air outside the ear to the fluid in the inner ear. Because fish live in fluid, that function is superfluous.

A Two-Way Street

While the professors’ research clearly influences their lectures, their teaching also impacts their research. 

When looking at fossils, evolutionary biologists often have to judge whether the attributes of a particular fossil are representative of the organism’s species. Sometimes that’s impossible to tell without seeing more samples. But Perry says that some features, like the branching of the major arteries of the heart, rarely vary from one individual to the next. “Dissecting human cadavers on a regular basis is useful for getting a sense of which features are likely to vary,” says Perry.

Kenneth Rose, who taught human anatomy for 36 years before retiring in August, agrees that he is much better prepared to interpret fossils because of his knowledge of human anatomy. “As anatomy faculty, we have to know all about the soft tissues of the body — especially muscles — and how they relate to the hard tissues of the body. This is especially important in my research on fossils, since soft tissues rarely fossilize. But we can make strong inferences about them thanks to our general anatomical training,” he says.

Ruff agrees that teaching anatomy influences the way he looks at fossils. “You only see a fossil’s bones — and usually not even all of them — but you know they were part of a functional system,” he says, like the system of bones, tendons and muscles required to raise your hand. 

But what really motivates these biologists to teach anatomy is their passion for the subject and their students. Perry believes he has a responsibility to teach evolutionary biology to counter efforts by some to remove evolution from the classroom. And Ruff, after 33 years of teaching, still says: “I’m always in awe of how well-put together the body is. We start from a single cell, and then everything gets sorted out somehow. That doesn’t mean it’s perfect, but it all works together. And the students see it too and are amazed.”