Flatfoot (pes planus) is a condition that occurs when the arch or instep of the foot collapses or touches the standing surface. It is also known as fallen arches or pronation of the feet.

The human foot is made up of 26 bones, 33 joints, and over 100 muscles, tendons and ligaments. The arch of the foot is created by tightening of the muscles and various ligaments that support the bones of the arch as well as ligaments that run from the heel to the ball of the foot. The arches distribute weight evenly across the feet and up the legs, and can affect walking. A well-developed arch is balanced between rigidity (for stability) and flexibility (for adapting to surfaces).

There are two types of flatfeet. Flexible flatfoot means that the foot has some arch, even if it only appears when the person flexes the feet or stands on the toes. This is a normal condition that is generally painless and does not require treatment. Stiff, inflexible, or painful flatfoot is an abnormal condition and may indicate a bone abnormality in the foot, a disease, or an injury.

Incidence and Prevalence of Flatfeet

Flatfeet are a normal condition in infants and toddlers. This is partly the result of fatty deposits along the bottom of the foot that go away as the child grows. It is also because the ligaments in the foot have not fully developed. Flatfootedness in children is generally painless and does not interfere with walking or activity. In fact, as children learn to walk, the soft tissues in the foot tighten and form the arch. Most children develop arches by late childhood.

When flatfeet continue into adulthood, most cases are considered normal. Incidence of flatfeet in the general population is unknown.

Publication Review By: Hai-En Peng, D.P.M.

Published: 16 May 2007

Last Modified: 15 Sep 2015