A person with flat feet has low arches or no arches at all. The arch, or instep, is the inside part of the foot that is usually raised off the ground when you stand, while the rest of the foot remains flat on the ground.
It is also known as fallen arches.
Most people have a noticeable space on the inner part of their foot (the arch). The height of the arch varies from person to person.
How can I tell if I have flat feet?
Flat feet are easy to identify while standing or walking. When someone with flat feet stands, their inner foot or arch flattens, and the foot may roll over to the inner side (known as over-pronation).
To see whether your foot over-pronates, stand on tiptoe or push your big toe back as far as possible. If the arch of your foot appears, it means that your foot is flexible and normal. If the arch does not appear, your foot is likely to over-pronate when you walk or run.
It can be difficult to tell if a child has flat feet as the arches may not fully develop until the age of 10.
Flat feet do not usually cause problems, but they can put a strain on your muscles and ligaments (the tissue that links two bones together at a joint). This may cause pain in your legs when you walk.
If you have flat feet you may experience pain in any of the following areas:
- inside of your ankle
- arch of your foot
- the outerside of your foot
- calf (the back of your lower leg)
- knee, hip or back
Some people with flat feet find that their weight is distributed unevenly, particularly if their foot over-pronates. If your foot over-pronates, it is likely that your shoes will wear out quickly. Over-pronation can also damage your ankle joint and Achilles tendon (the large tendon at the back of your ankle).
Why do I have flat feet?
Having low or no arches is normal for some people. In these cases, flat feet is usually inherited and the feet are fairly flexible.
Occasionally, flat feet can be caused by an abnormality that develops in the womb, such as a problem with a joint, or where two or more bones are fused together. This is also known as tarsal coalition and leads to the feet being flat and stiff.
Flat feet that develops in later life can be the result of a condition that affects the joints, such as arthritis, or an injury to a muscle, tendon or the joints of the foot.
Adult-acquired flat feet often affects women who are over 40 years of age. It often goes undiagnosed and develops when the tendon that supports the foot arch gradually stretches over time.
It is not fully understood what causes the tendon to become stretched, but some experts believe that wearing high heels and standing or walking for long periods may play a part. You are more at risk if you are obese, have high blood pressure (hypertension) or diabetes.
When to see a doctor
Most cases of flat feet do not cause any problems. However, you should go to see a doctor if you or your child have flat feet and:
- they are causing pain, even when wearing supportive shoes that fit well
- shoes wear out very quickly
- your feet appear to be getting flatter
- yours or your child’s feet are weak, numb or stiff
Treatment is not usually needed for flat feet because they do not usually cause any significant problems.
If you feel pain in your feet, the treatment includes:
- platelet rich plasma injection
- shockwave therapy
- surgery (rarely)
If your feet over-pronate, you may need to wear a special insole (orthotic device) inside your shoes to stop your feet rolling inwards when you walk or run.