Her only outlet was her art, she said, thanks to help from her older sister.

“I was like her little doll,” Ms. Riveros said of her sister. “She taught me how to grab a bottle with my feet, how to paint, and how to use my feet to fend for myself.”

In the early 1990s, her parents learned of a scholarship from the Association of Mouth and Foot Painting Artists of the World, an organization in Switzerland that supports disabled artists. At 7, Ms. Riveros applied for the scholarship by submitting two brightly colored paintings of clowns. She was accepted and offered a tutor and a monthly stipend of $400 for supplies. The next year, her work was shown at one of the association’s exhibitions, in Mexico City.

“When I began, I didn’t even know what art was,” she said. “But, thanks to the association, they helped me to discover that I am passionate about art.”

Over the years, Ms. Riveros grew more independent. She learned how to use her feet to bathe and dress herself, to wash her clothes, to open doors, and to embroider and sew clothing. When she was 12, she was offered the opportunity to receive prosthetic arms free of charge, but refused.