When the soles of the feet have little or no curvature, they are called fallen arches or flat feet, WebMD states. A person may be born with flat feet or develop them from health or environmental factors, including tendon or nerve damage, arthritis, dislocated bones, aging, obesity, diabetes and pregnancy.
In a normal foot structure, flexible bands known as tendons are attached to the bones and heels. Tendons work together and create tension that helps form the arched shape of most feet, according to WebMD. Fallen arches are often painless, but some individuals develop foot, leg and back pain. Their feet may also feel swollen, tired or restricted in movement. Persistent pain may lead physicians to recommend physical therapy or orthotic aids, such as special shoes or braces, to improve alignment.