Flat Feet: A flat foot is a foot without an arch. Heredity is the primary cause of flat feet. Many infants have flat appearing feet that lessen with time. There are different degrees of flat feet, however, and some children may not "grow out" of a having a low arch. A flat foot may lead to the formation of bunions, hammertoes, or heel pain. Leg, knee, hip and low back pain are also often associated with flat feet. An orthotic device can be used to help support and control the flat foot.