Flat feet, also known as fallen arches, have either no arch in feet or one that is very low. There is usually a gap beneath the inner part of the foot when a person stands, as the arch raises off the ground slightly. Flat feet only need treatment if they cause discomfort, indicate an underlying disorder, or lead to pain elsewhere in the body. Some children appear to have a very low arch or no arch without ever experiencing problems. When flat feet do cause symptoms, simple devices and exercises can help to minimize the discomfort.
Children with flat feet, also called “pes planus”, have a flattening of the arch during standing and walking. Flat foot is normal in infants and young children. At this age, in the absence of any associated symptoms, treatment is highly debatable. Flat foot usually naturally corrects itself as muscles strengthen and soft tissues stiffen. The height of the arch in the foot increases with age until about nine years. The problem is when flat foot persists, spontaneously occurs in older children or later in life, or is associated with pain and disability.
Flat feet can be flexible or rigid, painful or painless and associated with a tightness of the calf muscles (Achilles tendon). The majority of flat feet are painless, but when pain is present it is usually during weight-bearing activities such as walking and running. The pain can be in the sole of the foot, the ankle, or non-specific pain all around the foot area.
A human foot has 33 joints, which hold 26 different bones together. It also has over 100 muscles, tendons, and ligaments. The arches provide a spring to the step and help to distribute body weight across the feet and legs. The structure of the arches determines how a person walks. The arches need to be both sturdy and flexible to adapt to stress and a variety of surfaces.