Flat feet

The term flat feet (also called a fallen arch) is a medical condition in which human foot arches are very low or the entire sole of the human foot is touching the ground.

Flat feet
Other names	Pes planus, fallen arches

Flat feet in children may become regular arches later on. Adults with this condition may have problems involving arch development.

Lateral X-ray of a flat foot with C-sign, which is a bony bridge between the talar dome and sustentaculum tali, in combination with a prominent inferior border of the sustentaculum tali. This represents a talocalcaneal coalition, which is an abnormal connection between the talus and calcaneus and is thought to cause the flat foot deformity in this case.

The opposite, less common condition is called high arch.

Flat Feet Media

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  Grown male right foot (angle 1)

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  Flat feet of a child are usually expected to develop into high or proper arches, as shown by feet of the mother.

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  A woman in her thirties dorsiflexes, showing an absence of arches, over-pronated navicular and hallux valgus in the toes typically associated with flat feet.

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  Acquired Flat foot deformity with clinical soft tissue swelling.

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  Dorsoplantar projectional radiograph of the foot showing the measurement of the talonavicular coverage angle.

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  Weight-bearing lateral X-ray showing the measurement of calcaneal pitch, which is an angle of the calcaneus and the inferior aspect of the foot, with different sources giving different reference points. A calcaneal pitch of less than 17° or 18° indicates flat feet.

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  Same lateral X-ray showing the measurement of Meary's angle, which is the angle between the long axis of the talus and first metatarsal bone. An angle greater than 4° convex downward is considered a flat foot, 15° - 30° moderate flat foot, and greater than 30° severe flat foot.