What Is the Purpose of the Arch in Our Foot?

The arch of the human foot is a complex structure made up of three separate arches, as well as ligaments. The shape of the foot arch varies from person to person. Some people have normal arches, while others have high or low arches. The shape of the arch affects how a person walks, and arches that are too high or too low can cause foot pain and knock-kneed or bowlegged stances.

Arch Composition

• The arch of the foot is comprised of three arches: the medial longitudinal arch, the lateral longitudinal arch and the transverse arch. Both the medial longitudinal and lateral longitudinal arches run the length of the foot. The medial arch is located on the inside of the foot, while the lateral runs along the outside. The medial longitudinal arch has the most distinctive arched shape, while the lateral arch appears flat in most people who do not have high arches. The transverse arch, on the other hand, runs perpendicular to the other two and is responsible for foot movement and flexibility. These arches, combined with a series of ligaments, help you to walk properly, balance and support your body weight.

High Arches

• High arches are characterized by higher than average lateral and medial arches. People with high arches have a noticeable space between the ground and their foot when they stand barefoot on a flat surface. The space is most visible on the inside of the foot, but some people with high arches have a space under the lateral arch as well. High arches affect the mechanics of walking, as they cause the ankles to turn inward and create a knock-kneed stance. High arches are treated with orthotic footwear, including arch supports, which help the foot absorb the shock from each step.

Low Arches

• Low arches, commonly known as flat feet, create the opposite effect as high arches: they cause the ankles to roll outward when walking and cause bowleggedness. There was a time when low arches were considered undesirable and even a risk for injury, resulting in flat-footed people being rejected from the U.S. Army. People with low arches actually have a lower rate of arch injury than their high-arched counterparts due to less stress on the ligaments in the arches. The arches absorb the impact of walking and running, so low arches actually have less ligament strain and offer less resistance to impact.

Normal Arches

• Normal arches are somewhere between flat feet and high arches. There is a visible arch on the inside of the foot, but the outside appears nearly flat when walking in bare feet. Normal arches make for optimized walking; they best support weight, the key function of the arch, and absorb the impact of walking. People with normal arches have lower incidence of arch-related foot pain than those with high arches, and as a result, lower incidence of the leg, knee and back pain that can develop as a result of abnormal arches.