Flat feet is when one or both feet have no arches or arches that are very low. This can cause feet to lie fully flat on the ground, which can impair a person’s posture. Flat feet may also cause pain and discomfort.

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Doctors may refer to flat feet as fallen arches or pes planus. When a person has flat feet, there is usually a gap beneath the inner part of the foot when a person stands, as the arch raises off the ground slightly. Things to know about flat feet include the following:

  • Children can get flat feet, but they usually outgrow the condition.
  • Adults who develop flat feet usually have an underlying condition that is affecting their feet.
  • The symptoms include pain, swelling, or stiffness affecting the arch of the feet, legs, and sometimes the back.

Flat feet only need treatment if they cause discomfort, indicate an underlying disorder, or lead to pain elsewhere in the body.

Some people appear to have a very low arch or no arch without ever experiencing problems. When flat feet cause symptoms, simple devices and exercises can help minimize discomfort.

This article provides more detail about the causes, symptoms, and treatment of flat feet.

People with flat feet have a very low arch or no arch, meaning that one or both feet may be flat on the ground.

Flat feet can affect the body’s alignment when a person is standing, walking, or running. As a result, having flat feet can increase the likelihood of developing pain in the hips, knees, and ankles.

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Flat foot, also called pes planus, is a deformity of the foot where the arch has not developed fully.
Nassoro DD, Torres L, Marando R, Mboma L, Mushi S, Habakkuk Mwakyula I. A child with duchenne muscular dystrophy: A case report of a rare diagnosis among Africans. Clin Case Rep. 2020;8(12):2654-2660. Published 2020 Aug 18. doi:10.1002/ccr3.3254
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Flat foot in an adult can cause foot pain for certain people.
Drvgaikwad, CC BY-SA 3.0, via Wikimedia Commons
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A flat foot is a common foot condition where there is loss of the median longitudinal arch, resulting in a flat-looking foot.
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A typical foot arch.
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How do flat feet develop?

A typical 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.

When people have flat feet, their feet may roll to the inner side when they are standing and walking. This is known as overpronation, and it may also cause the feet to point outward.

People often develop flat feet in childhood. However, the condition can also develop in adulthood. Many people with flat feet have no symptoms, but others will experience various symptoms that generally depend on the severity of the condition.

Generally speaking, there are two types of flat foot conditions:

Flexible flat foot

This condition more commonly affects children. When the child stands, the arch of their foot will disappear. When seated or walking on tiptoes, the arch will be visible again.

Rigid flat foot

When a person has a rigid flat foot, they will not have an arch regardless of whether they are placing weight on their foot, such as when standing. This condition can affect children and can develop in adults.

The most common symptom of flat feet is pain in the feet. This can occur as a result of strained muscles and connecting ligaments.

Abnormal stresses on the knee and hip may result in pain in these joints. These stresses are likely if the ankles turn inward.

Pain, and sometimes swelling or stiffness, most commonly affects the following parts of the body:

  • ankle
  • arch of the foot
  • calf
  • knee
  • hip
  • lower back
  • lower legs

Flat feet can also cause an uneven distribution of body weight. This may result in shoes wearing down unevenly or more quickly than usual, especially on one side, which can lead to further injuries. People may have difficulty walking or running evenly.

The causes and risk factors for developing flat feet are intertwined. Some factors that can put a person at risk for the condition may also cause it.

The common risks include:

  • obesity
  • pregnancy
  • diabetes
  • trauma to the feet
  • having family members with the condition
  • developing a condition that can affect the tendons
  • being of young age or being an older adult

Common causes include:

  • genetic factors, as flat feet can pass from parents to children in the genes
  • weak arches, meaning that the arch is visible when a person sits but the foot flattens onto the ground when they stand
  • foot or ankle injuries
  • stress on the arches of the feet due to excess weight
  • arthritis or rheumatoid arthritis
  • damage, dysfunction, or rupture of the posterior tibial tendon
  • nervous system or muscle diseases, such as spina bifida, muscular dystrophy, or cerebral palsy
  • tarsal coalition, which causes the bones of the foot to fuse together unusually, resulting in stiff and flat feet
  • long-term use of the feet, which can cause cause the posterior tibial tendon, the primary support structure for the foot arch, to weaken in older age
  • tendonitis, which is a tear due to overuse, or other damage to the tendon
  • developmetal anomalies that can develop in childhood, with age, or after pregnancy

Babies are usually born with minimally visible foot arches, and it can take time to develop arches that remain consistent. When a child has flexible flat feet, this may not happen until after the age of 5.

Most children with flat feet will usually develop typical arches by age 10, and having feet that appear flat during early childhood does not mean that a person will always have flat feet.

However, if a child has flat feet due to incorrect bone development or another condition, such as spina bifida, a doctor will often need to treat the underlying cause.

When flat feet develop in adulthood, there is usually an underlying medical cause.

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Flat foot in a child.
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The arch of the foot slowly develops over time and becomes fully developed by ages 2 or 3 years. It is usual for infants and young children to have flat feet.
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An image of typical feet in a baby.
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Specific exercises can help people experiencing foot or arch pain.
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People with flat feet who do not experience pain or other symptoms usually do not need to consult a doctor.

However, anyone with the following symptoms should seek medical advice:

  • flat feet that have only developed recently
  • pain in the feet, ankles, or lower limbs
  • symptoms that do not improve with supportive, well-fitted shoes
  • one or both feet becoming more flat
  • the feet feeling rigid, stiff, heavy, and unwieldy

Most qualified healthcare professionals can diagnose fallen arches by examining the feet and observing the individual standing and walking.

The doctor will inspect the feet from the front and back. The individual may need to stand on the tips of their toes to allow the doctor to examine the shape and functionality of each foot.

A doctor will also consider the person’s medical history. They may order an X-ray, CT scan, MRI scan, or electromyography in some cases.

A podiatrist or physical therapist may recommend specific exercises to manage the symptoms of flat feet or prevent them from developing.

In a 2020 study, researchers found that participants’ gait and foot alignment improved after just 8 weeks of foot exercises.

The American Academy of Orthopaedic Surgeons recommends the following exercises to improve strength and flexibility in the feet and ankles, which may help to relieve symptoms of flat feet.

Heel cord stretching

A tight Achilles tendon will encourage the foot to roll inward. The aim of heel cord stretching is to stretch the Achilles tendon and posterior calf muscles.

To perform heel cord stretching, a person should:

  1. Stand facing a wall and place one hand on the wall at eye level.
  2. Place the leg that needs stretching approximately one step behind the other leg, and plant the heel firmly on the ground.
  3. Bend the knee of the front leg until you feel a stretch in the back leg.
  4. Hold for 30 seconds and then rest for 30 seconds.
  5. Repeat nine more times. It is essential to avoid arching the back and to keep it straight.

People should perform this exercise twice a day.

The golf ball roll

This exercise requires a chair and a golf ball.

Sit on the chair with your feet firmly on the ground. Place the golf ball under the foot, and roll it forward and back under the arch of the foot for 2 minutes to stretch the plantar fascia ligament.

Some people with flat feet may automatically align their limbs in a way that prevents symptoms. People who are not experiencing symptoms do not usually require treatment. If flat feet are causing pain, then supportive, well-fitted shoes can help. Extra-wide-fitting shoes can provide relief.

Children do not usually need treatment for flat feet. If they experience pain, they may need to use fitted insoles and orthotics. Custom-designed arch supports may relieve pressure on the arch and reduce pain if the feet roll too far inward.

Some bones do not develop properly in childhood, which can result in flat feet from birth continuing into adulthood. In these rare cases, surgical intervention may be necessary to separate fused bones.

Adults may also use foot orthotics, and people with posterior tibial tendonitis might benefit from inserting a wedge into their footwear along the inside edge of an orthotic. This should relieve some of the load that the body places on the tendon tissue.

However, it is important that a person uses orthotics under the supervision of a doctor, as using the wrong orthotics or using them improperly can worsen symptoms.

A person can also take nonsteroidal anti-inflammatory drugs for pain relief. In cases where obesity is a contributing factor, a doctor may recommend eating a healthful diet and exercising to reach a healthy body mass index and reduce the stress on the arches.

Wearing an ankle brace may also be beneficial until the inflammation reduces. Doctors may advise some people to rest until their symptoms improve and avoid activities that might aggravate the foot or feet.

A person with arthritis or a ruptured tendon might find that a combination of using insoles and taking pain relievers can minimize their symptoms. If these do not work, surgery may be necessary.

Children with flexible flat feet will often outgrow the condition. When a person has a rigid flat foot or the cause is an underlying condition, their outlook will depend on their specific symptoms and the required treatment.

Treatment can be difficult when the cause is a degenerative disease and symptoms worsen over time. Where surgery is necessary, a person’s outlook is generally good. Exercising can help improve the outlook for some people. However, having flat feet may also mean that a person will need to avoid high impact activity.

A person should consult a doctor to determine the best treatment plan for them.

People with other foot, ankle, or lower leg problems may find that flat feet can contribute to them or worsen symptoms.

Examples include:

Flat feet occur when a person has a minimal or absent foot arch, often causing problems with walking and sometimes pain. There are different causes of flat feet, and not all types of the condition will cause discomfort and symptoms.

When the condition develops in childhood, it usually goes away as the child grows up. Treatment may be necessary if there is pain or impact on a person’s early life. This usually involves foot orthotics and anti-inflammatory medications. In rare cases, a person may need surgery.