The fifth toe, also known as the pinky toe, the little toe, or the baby toe, is usually the smallest toe on the human foot. This toe is found at the outside edge of the foot, furthest from the big toe. The structures of the pinky toe include the fifth metatarsal bone. The flexor digiti minimi brevis and abductor digiti minimi muscles help the fifth toe move and function properly. There are a number of medical conditions and deformities that can afflict the fifth toe, including corns, hammertoe, underlapping, and overlapping. Surgery can usually correct these problems to some degree.
Conditions of the fifth toe include underlapping and overlapping. Underlapping and overlapping of the pinky toe typically occur when the toe is tucked underneath of, or rests on top of, the adjacent fourth toe. These conditions are believed to be hereditary and are usually present from birth. Underlapping and overlapping of the smallest toe are believed to occur equally in both boys and girls, and usually appear on both feet.
Hammertoe is another medical condition of the smallest toe. This condition usually occurs when the toe becomes permanently fixed in an abnormally bent position. It's usually blamed on the wearing of high heeled or ill-fitting shoes.
Some of the most common medical problems of the fifth toe are corns. Podiatrists typically place corns into two categories, soft and hard. Hard corns typically resemble calluses and usually form on the sides of the toes. If a hard corn forms on the inside of the toe, it can rub against the opposite toe, contributing to the formation of another corn on that toe, which podiatrists often refer to as "kissing corns." Soft corns usually form in the soft, webbed flesh between toes.
Scientists who study evolution now suspect that humans evolved short toes, such as the pinky toe, because they can help us run fast for long distances. From an evolutionary standpoint, scientists believe, the ability to run fast enabled early humans to hunt larger, faster prey, especially herd animals. This may have enabled early humans to meet the dietary requirements necessary for the growth of a large brain. Some evolutionary scientists believe if human evolution is allowed to continue on its current track, the smallest fifth toe on the foot will eventually disappear, since it serves little purpose in modern human life.