Pes planus involves collapse of the arch of the foot so it comes into contact with the ground. This can be a result of the foot arch never developing properly, a trauma to the foot, or a progressive flattening of the foot over time. Flat feet are common, and most are considered variations of normal. However, stiff, inflexible or painful feet require attention as they may be associated with other problems.
Family History
Pes planus can be a genetically inherited condition. If the flat feet are not causing any functional problems or pain, they are considered normal, and need not be addressed.
Tarsal Coalition
Tarsal coalition is a result of two or more bones of the foot fusing together. This fusion limits the motion of the foot and can lead to a flattened arch. This condition is present in some children and can cause painful flat feet.
Pronation
Pronation is a condition in which the ankle bones lean inward toward the centerline of the body. This foot position will create a flattened arch.
Nervous System or Muscle Diseases
One disease that may cause pes planus is cerebral palsy. This disease can cause muscle paralysis with a loss of sensation. Muscles can also be over- or underdeveloped with this disease, and that can cause problems with the structural integrity of the foot and possibly pes planus.
Injury
The tibialis posterior tendon is the main structural support for the foot arch. An injury to this tendon that causes a rupture could create flatfoot.
Age
Long-term wear and tear of the feet, brought on by walking, running and jumping, can cause a weakened posterior tibialis tendon. As this tendon weakens, it loses its ability to support the foot arch, and allows the foot to flatten.
