by EBSCO Medical Review Board
(Pes Planus; Pes Planovalgus; Fallen Arches)


A flat foot is a foot that has lost or never developed an arch.

Normal Foot Arch
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Infants and young children naturally have flat feet. The arch should develop over time. Sometimes, the arch does not develop. It is not always clear why this happens.

Causes may be:

  • Rupture or damage to the tendon that supports the arch
  • Health problems that affect the muscles or nerves in the foot
  • Ligament damage in the foot
  • Changes in certain foot joints over time

Risk Factors

In newborns, this problem is more common in girls. In children who are 3 to 8 years old, this problem is more common in boys. In adults, this problem is more common in women after age 55 years of age.

Other things that may raise the risk in children are:

  • Loose joints
  • Sitting on his or her bottom with both knees bent in a "w" shape
  • Delayed nerve and muscle development
  • Obesity


Some people may not have problems. Those who do may have:

  • Pain
  • A stiff foot
  • Foot weakness
  • Calluses, blisters, or skin redness on the inner side of the foot
  • Balance problems
  • Problems walking or running


You will be asked about your symptoms and health history. A physical exam will be done. It will focus on your feet. This is often enough to make the diagnosis.


People without symptoms may just need to be monitored. People who do have symptoms may need to see a doctor who treats feet. Options are:

  • Physical therapy and exercises to stretch and strengthen the muscles of the foot
  • Shoe inserts to support the foot or shoes with a good arch support
  • Braces to treat flat feet caused by nerve or muscle problems

People who are not helped by these methods may need surgery to create an arch.


There are no known guidelines to prevent this problem.


Foot Health Facts—American College of Foot and Ankle Surgeons 

Ortho Info—American Academy of Orthopaedic Surgeons 


Canadian Federation of Podiatric Medicine 

Canadian Podiatric Medical Association 


Adult acquired flatfoot. Ortho Info—American Academy of Orthopedic Surgeons website. Available at: Updated September 2017. Accessed July 30, 2020.

Flat foot signs and symptoms. UCSF Children’s Hospital website. Available at: Accessed July 30, 2020.

Pes planus (flatfoot). EBSCO DynaMed website. Available at: . Updated September 26, 2017. Accessed July 30, 2020.

Toullec E. Adult flatfoot. Orthop Traumatol Surg Res. 2015 Feb;101(1 Suppl):S11-17.

Revision Information