“Bound Feet in China,” a 1937 article in The Journal of Bone and Joint Surgery, gives one of the few detailed physical descriptions of foot-binding currently available, but still couches the cruelty of the process in metaphor and largely ignores the lasting health consequences. “The four outer toes are flexed upon the sole and are held in that position,” the authors wrote. “The metatarsals are pressed together as the bandages are applied. In spite of the pain after each kneading, the girl is forced to walk, in order to help re-establish circulation.” In plain English, that means that all of a girl’s toes except the first were crushed toward the bottom of her foot and bound with cloth strips. The process could start when she was as young as 3 years old, though 5 was more common, and was repeated for two or three years—her toes routinely rebroken and bound again more tightly.

In many cases the intense pain of foot-binding was exacerbated by infection (which sometimes led to gangrene), hindered circulation, and weakened bones and ligaments. A girl’s feet typically remained bound with bandages and strips of either silk or cotton, depending on what her family could afford, for the rest of her life.

Humans took millions of years to evolve into bipedal walkers, relying on several points of the foot shifting weight and balance as we take each step. Foot-binding reduced these points to only the big toe and heel bone; the arch was shoved up to make the foot shorter, and the other toes were bent under the ball. In many cases the arch was broken completely. Girls whose feet were bound would never again be able to walk fluidly, severely limiting their ability to move through the world.

Many cultural accounts of foot-binding have been written, especially from a feminist perspective, and many academic studies mention the process. But for one of the only medical descriptions of foot-binding’s long-term consequences, we have to turn to Steve Cummings, an epidemiologist and professor emeritus at the University of California at San Francisco.

Cummings went to Beijing in 1991 to study why older Chinese women had 80 percent fewer hip fractures than American women of the same age range. He and a team of researchers randomly selected neighborhoods from each of Beijing’s central districts, then visited every house that they knew had a woman over the age of 50. They invited more than 300 women to a lab at Peking Union Medical College Hospital, where participants performed a series of regular motions (e.g., standing from a chair with their arms crossed, squatting) along with tests for grip strength and gait speed.

The second participant in the hip-fracture study “came in with two canes and her foot wrapped up oddly,” Cummings told me. “I thought it was just curious.” By that time, he had been living in Beijing for two or three months, and he and his family had traveled extensively through the city and around the country. During those travels, he had never once seen a woman with her feet in the same condition as those of the second study participant.