A fallen foot arch results in a flat foot. Normally you should see an arch in the bottom of your foot which is created by the tendons pulling in your feet.
Besides congenital deformities, weak ligaments and muscles are primarily responsible for fallen arches. They can often occur when the arches of the feet do not grow properly during childhood. Lots of people experience no pain or discomfort as a result of flat feet. Even if there are no symptoms at first, however, higher loads on the ankle or knee due to misalignment can lead to problems in the knees and back eventually.