Frida suffered a bout of polio at age six, which left her right leg looking much thinner than the other (a deformity Kahlo hid by wearing long skirts). Nevertheless, Frida's feisty personality as well as her father's encouragement led to her participation in boxing and other "manly" sports, which helped her overcome her disability.
In 1925, when she was 18, she was riding a bus in Mexico City when it was struck by a trolley car. A metal handrail pierced her abdomen, exiting through her vagina. Her spinal column was broken in three places. Her collarbone, some ribs, and her pelvis were broken, and her right leg was fractured in 11 places. Her foot was dislocated and crushed. No one thought she would live, much less walk again, but, after a month in the hospital, she went home. Encased for months in plaster body casts, Kahlo began to paint lying in bed with a special easel rigged up by her mother. With the help of a mirror, Kahlo began painting her trademark subject: herself. Of the 150 or so of her works that have survived, most are self-portraits. As she later said, "I paint myself because I am so often alone, because I am the subject I know best."