This foot type is a result of the fact that all people are born with different physical features. Any alteration in the many building blocks of the foot can influence its shape. At the other end of the spectrum, yet within the same category of congenital flat foot, exist several rare, more severe forms of flat foot. Luckily, these are much less common, but can usually be identified by specialists at the time of presentation and treated appropriately. The second category, acquired flat foot , develops over time, rather than at birth.
Many different factors can contribute to the development of flat feet.
These include the types of shoes a child wears, a child's sitting or sleeping positions, compensation for other abnormalities further up the leg, or more severe factors such as rupture of ligaments or tendons in the foot. Very commonly, the reason for flat feet is that the foot is compensating for a tight Achilles tendon. Even minimal amounts of plantarflexion can simulate a longer leg on that particular side, assuming that the other foot is in the normal position. The body therefore tries to compensate by pronating, or flattening out the arch, thereby making up for the perceived extra length on the affected side. As the body ages, ligaments and muscles can weaken, leaving the job of supporting the arch all to this tendon.