Flatfeet

Pes planus means having flat feet — or one flat foot — with little-to-no arch in the sole. You may be flat footed from childhood, or your feet may have lost their natural arches due to a medical condition.

Babies are naturally flat footed, but most begin to develop arches when they start walking. If arches never develop, or if they collapse later in life, flat feet can cause pain or other problems with walking.

Why do foot arches matter?

The arches of your feet play an important role in the mechanics of walking upright. This is why they’re unique to human primates. Your arches are made of bones and connective tissues. They:

• Act as a springboard and shock absorber
• Store and release energy as you walk
• Adapt your foot to uneven walking surfaces
• Protect nerves and vessels in the soles of your feet

Are there different types of flat feet (pes planus)?

Some healthcare providers make a distinction between mildly flat feet that don’t cause any issues and the foot deformity they call pes planus. With pes planus, flat arches cause other changes to your foot.

Pes planus means:

• The arch on the inner side of your sole is flattened and appears to touch the ground.
• The flattened arch causes your heel to point outward and your ankle to roll inward.
• Your talus bone, a bone on the inner side of your foot, sticks out.

Providers may classify your flat feet as flexible or rigid (sometimes flat or always flat). Flat feet can also be congenital (due to conditions present at birth) or acquired (something that happens later in life).

Types include:

• Flexible flat foot. Flexible flat feet are the most common type. With this type, you can see arches in your feet when you aren’t standing on them, but they disappear when you stand.
• Rigid flat foot. If you have rigid flat feet, your feet have no arches whether you’re standing or sitting. You may find it difficult to flex your feet up and down or side to side. This type is rare.
• Congenital flat foot. Some babies have a birth defect that prevents their feet from developing arches. Some hereditary connective tissue disorders can make your arches too weak to hold up.
• Acquired flat foot (fallen arches). Also known as progressive collapsing foot deformity, this condition happens in adulthood, or after your feet have developed their natural arches.