Foot Structure

Three Arches

The bones of the foot are arranged into 3 arches:

• Medial Longditudinal arch (the biggest and most recognisable arch, along the inner side of the foot);
• Lateral Longditudinal arch (smaller arch along the outer side of the foot);
• Transverse arch (arch across the front part of the foot, which because of its' location can't be seen in action).

Together, these arches provide strength and stability to the foot. Here's how:

Three Keystones

The most important component in any arch structure is the Keystone. This is the stone which forms the apex of the arch and holds the entire structure together.

Arch bridges are classic examples of this type of architecture, and were designed and built because of their strength and stability. Some of the oldest ones, built by the Romans around two thousand years ago, still remain standing today.

In the foot, there are three keystones - one for each of the arches:

With the Keystones in place, the mixture of location and size of the arches combine to create an incredibly strong and stable foot structure.

Three Important Bones

Of all the bones in the foot, the Talus, Cuboid and Middle Cuneiform are structurally very important. If one or more of these three bones is out of alignment, the structural integrity of the arch it supports, and in turn the strength and stability of the entire foot becomes compromised.

The line drawings above have been sourced with permission from the book "Foot Orthoses and Other Forms of Conservative Care", by Thomas Michaud, 1993.