Bruckner's Anatomy

A physical therapist's stunning discovery that your two feet may not be alike. And that's why they hurt

By Will Hively|Monday, November 01, 1999


Jan Bruckner, a professor of physical therapy at Thomas Jefferson University in Philadelphia, strides across campus on a balmy morning, heading for a 10 a.m. appointment at the Human Performance Laboratory. There, Gary Sylvester, one of Bruckner's students, nervously waits. He has responded to her standing offer to examine any pupil who complains of foot pain.There, Gary Sylvester, one of Bruckner’s students, nervously waits. He has responded to her standing offer to examine any pupil who complains of foot pain.

Sylvester frets that his complaint is trivial, and when Bruckner begins the evaluation by asking his age, he is so nervous he snaps to attention. “Twenty-three,” he announces. “All of 23?” says an older woman being treated for a serious foot problem in the same lab. She chuckles, then sighs and listens jealously as Sylvester explains that he runs 15 miles a week. His feet rub inside his shoes, get raw around the toes, and develop blisters. “Anything else?” Bruckner asks. “Any other problems?” That’s it.

She listens as Sylvester describes how he has been plagued by blisters since he ran track in high school. He had come to accept them, but now he has begun to wonder why other runners  don’t have this problem. What’s wrong with his feet?

Sitting down to face Sylvester, Bruckner lifts one foot toward her and gently manipulates the joints from toe to heel, focusing on his hindfoot. Clamping the forefoot in one hand and bracing it on her thigh, Bruckner flexes the heel and wiggles it from side to side. It’s a good thing you came in, she says. The blisters are harbingers of real trouble. Structurally, Sylvester’s feet are the feet of the future, the next evolutionary step for humans, but as yet no shoe store stocks sneakers to accommodate them.

Sylvester is far from alone. Bruckner says anywhere from 30 to 80 percent of us have feet like his, leaving many people with a stiff hindfoot that shoes can’t support properly. And after years of clinical practice, anthropological research, and pioneering studies, Bruckner has concluded that biomechanically speaking, there’s no such thing as a normal human foot. Instead there is a spectrum of variations, none more normal than any other. Although everyone has the same basic bones and muscles, the parts aren’t always connected the same way. Biologically, the foot remains a work in progress, and it needs a lot more help from the shoe industry than it’s getting. No part of the body takes more of a beating than the foot. If Sylvester hadn’t bothered to show up today, his blisters could have easily become heel spurs, which could then undermine his ankles and knees. Eventually his minor complaint would have turned into chronic pain. But because he is still young, a simple, custom-made shoe insert designed by Bruckner will save his feet.

Bruckner is a quiet, polite revolutionary driven to save the world’s feet.

She has worked in relative obscurity, refining her theories of the lowest human appendage for 15 years without major grants or corporate backing. Her work has become a crusade. She believes each and every schoolchild should receive a foot evaluation, just as each and every one now gets an eye examination. Prescription glasses are available to almost anyone, she says, so why aren’t prescription shoes? Knowing your own foot type should be as vital as knowing your blood type, especially in light of a recent poll showing that half of all Americans say they suffer from some kind of foot or ankle problem. For one in five, those problems will force a change in activities.

Bruckner wasn’t always a crusader for the foot. As an undergraduate at Barnard College during the Vietnam War, she studied anthropology with Margaret Mead. It was then that she first realized that physical therapy, if done properly, is a form of applied anthropology. “These patients have culture, values, and kinship,” Bruckner explains. Her senior year, she did an ethnography of St. Luke’s Hospital’s physical rehabilitation department and documented the behavior of the physical therapy staff. “And like many anthropologists before me,” Bruckner says, “I studied this quaint culture and went native.” Bruckner enrolled at Boston University for a master’s in physical therapy.

As a graduate student, Bruckner accepted what she was taught, that the foot, a bewildering heap of 26 bones and 23 joints, is a marvelous biomechanical contraption that propels humans with speed and remarkable control—proof of evolutionary adaptation. “I thought it was incredibly cool,” she says.

In May 1977, the year after receiving her degree, Bruckner began working with senior citizens at a nursing home in Rochester, New York. Before long she began to realize that the miracles of evolution didn’t hold up very well. In fact, in far too many people, feet seemed destined to fail.  “I got very frustrated,” she says. “My patients had tremendous problems walking.” Once their feet went, they suddenly seemed much older. “I thought, if this mechanism is so cool, how come there are so many people with so many problems?”

After eight years of practicing physical therapy, Bruckner wanted more information about the foot’s biomechanics. She turned to her first passion and enrolled in the physical anthropology program at Indiana University. Bruckner began reading old anthropology studies about bones and joints, work considered irrelevant in the medical community. “I discovered something that they’d never taught me when I studied anatomy in physical therapy,” she says. A few anthropologists had written about a wide range of shapes and configurations of the human foot, variations that modern textbooks never mention. In particular, the shape of the talus bone—directly above the heel and below the lower leg bone—differs widely among humans. Visually, these anomalies don’t amount to much. Mechanically, however, Bruckner suspected they might mean a great deal.

The variations that seemed most important to her occur in a joint called the subtalar, where the rounded talus bone fits into the knobby calcaneus, or heel bone. The bones’ irregular forms usually touch each other at two or three distinct points called facets—flat areas roughly the size of a thumbnail. Bruckner realized that a joint with three facets would be stable and rigid, like a stool with three legs, and would restrict motion and allow more shock to shoot through the foot into neighboring joints. Two-faceted joints, on the other hand, would allow greater flexibility. Three facets looked like trouble and Bruckner wasn’t sure how that variation affected modern humans. It turned out that nobody else knew, either.

To find out, Bruckner needed lots of feet. She began with the dead. Because she taught in the physical therapy department at the university’s medical school, Bruckner had access to the cadavers used in anatomy classes. She dissected the feet of more than 30 bodies and tallied more three-faceted than two-faceted joints. More disturbing, she found that one-third of the bodies had a two-faceted joint in one foot but a three-faceted joint in the other, or vice versa, violating left-right symmetry found elsewhere in the body. In her small but random sample, Bruckner didn’t find a single normal pair of feet.

She began to wonder what happens to the knees, hips, and lower backs in people who have mismatched shock absorbers in their feet. How well would they walk when they reached middle age? She began to suspect that all sorts of aches and pains could be traced down the skeleton to these little-known variations in the feet. A lopsided arrangement in the feet presented what Bruckner called an “interesting physics problem” for the rest of the body to solve.

To continue her research on the living without using surgery, she developed a technique for wiggling patients’ heels to reveal three-faceted joints. But she still needed a live group of research subjects and found them by chance when she filled in as a temporary physical therapist with the Tohono O’odham (pronounced like autumn) tribe of southern Arizona.

The O’odham have one of the highest rates of non-insulin-dependent diabetes in the world. Patients lose sensitivity in their feet and then overlook sores such as those created by shoes that rub. It can take only a month for a tiny infected foot sore to become gangrenous, which can mean amputation.

In 1987, Bruckner struck a deal with the tribe: She agreed to work at the reservation’s clinic without pay if she could examine the feet of any willing member of the tribe. Because the O’odham are a relatively homogeneous population, Bruckner half expected to find almost no variations in their feet. “They’re about as close to genetically isolated as you’re going to find in North America,” she says. Instead, she found wide deviation in the subtalar joints.

She still needed a research pool more diverse than the O’odham. In the winter of 1989, the Persian Gulf War delivered them almost to her front door. As troops were shipped to the gulf, Bruckner went to work for the U.S. Army at Fort Benjamin Harrison in Indiana, treating the sprained ankles, broken bones, blisters, and shinsplints of infantry soldiers in training. She worked for free, under the proviso that she could examine the healthy feet of anyone on the base who volunteered for her research. Again she found plenty of variation—and something else. If a soldier had a three-faceted joint in one foot and a two-faceted in the other, the odds for injury were higher. “What was even more devastating than facet configuration,” she says, “was asymmetry.”

Bruckner finally had enough data to support her theory, but she didn’t stop there. She approached the O’odham about starting a shoe factory with money they’d recently received from an old mining claim. “I told them, ‘I know how to make really good shoes for people with diabetic, insensitive feet. ’ ” The tribe was enthusiastic, she says, but cautious, and no agreement was ever reached on building a factory.

Bruckner also approached the captain in charge of the clinic at Fort Benjamin Harrison. “I said, ‘You have to stop issuing shoes by the pair. Issue shoes by the each.  The soldiers in our clinic with problems have one foot significantly different from the other.’ ” The officer stared at Bruckner for what seemed like a very long time. “Lady,” she remembers his saying, “this is the Army. We can’t do that.”

Bruckner didn’t give up on her dream of perfect shoes for the masses. In 1996, she met Dimitris Metaxas, a computer scientist at the University of Pennsylvania. He invited her to take a look at a program called Jack™, a computer model of a person who exists only on-screen and was designed to create better workstations. For example, while auto engineers design a car on a computer, Jack sits in the virtual driver’s seat, letting the engineers know if he can see all the controls. Bruckner immediately saw the program’s potential to help her design shoes to fit every foot in the world perfectly. But while Jack’s upper body seemed to accurately replicate a human’s, his feet were another story. “Jack walked like a robot,” she says, “Jack had no subtalar joints. His feet looked like slabs of meat.”

Although Jack is now owned by a private company that contracts the program to corporations, seeing him lured Bruckner to Philadelphia: She needed virtual patients to model virtual shoes, and the center’s programmers could build them. One computer scientist at the Center for Human Modeling and Simulation “freaked out,” Bruckner remembers, when she said the computer needed to mimic the 26 bones and 23 joints of a real human foot. Metaxas, however, found the challenge intriguing and the two began collaborating. Last year Bruckner moved to Philadelphia to be closer to the center.

Two computer models are under development. One is a gait model that walks according to an individual’s variations. Until now, every gait model worked from an ideal algorithm. “Nobody walks like anybody else, much less with an ideal gait,” Bruckner says. The other model represents a person’s foot, and then designs the shoe the person needs to wear. “I want to put these two programs together and run clinical studies. I want to use these intelligent programs to fabricate shoes and make orthotics.” That day is at least five years away. At this point the models only simulate the hindfoot; the front of the foot remains to be completed. “A lot of the work is done, but the whole project has a long way to go,” Bruckner says.

In the meantime, Bruckner is rounding up future test cases for the day when a computer can simulate any foot and design a perfect shoe. One Thursday evening a month, she noses her gray 1988 Chevy Nova through an urban maze of one-way streets to the Gateway Center, run by the Salvation Army. Here, in a classroom where all the desks have been pushed aside for the evening, Bruckner sees homeless patients who would otherwise rarely, if ever, see a physical therapist.

Bruckner wants her computer model to make better shoes for these patients. “If I can get these people better shoes, I can get them walking. If they walk, they can work. This isn’t research just for the fun of it. This is service.” Her colleagues at the simulation center “don’t seem to fully realize yet they’ll have indigents in their computer lab,” she says. “We’ve talked about this, but I don’t think it sank in.”

Eventually she hopes to establish a permanent clinic where paying patients will get such extraordinary treatment, not to mention custom-designed shoes, that they’ll happily sit side by side with homeless patients. “But a clinic is too limited, too narrow. Whoever needs this model should have it available.”

Tonight, as Bruckner parks at the center, an overweight middle-aged woman crosses the street toward her, smiling, calling out a greeting, and dragging one of her feet. Nine months ago she fell down a flight of stairs. No break showed up on an X ray, so she continued walking on the foot, despite pain.

Bruckner has seen her fairly regularly for the past year, suspecting that a fractured navicular bone might be pushing into other bones and soft tissue with every step. She says the woman needs a ct scan, but that would cost about $800. And then she might need surgery. A physician at the clinic has given the woman pain pills instead.

As Bruckner and the woman talk on the sidewalk, people begin emerging from the shadows, heading toward the center. One is Gary Sylvester, the runner she examined earlier today. Then another of Bruckner’s students shows up, and another. Before long, more than six physical therapy students from the university have come to put in a long evening working on the feet of homeless people. Bruckner is no longer alone.



To find out more about the University of Pennsylvania's Center for Human Modeling and Simulation and about the Jack software system created there
or to look at what Jack is being used for today John Langdon's Web site at the University of Indianapolis

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