THE FOOT

The human foot is a mechanical and medical marvel. It can sustain enormous pressure (several tons over the course of a one-mile run) and provides flexibility and resiliency during the thousand of steps we make everyday.

Foot pain is not normal and should not be ignored; problems can affect the functioning of other parts of the body, including the hips, knees, and back.

The foot contains 26 bones (a quarter of total number in the body), 33 joints, more than 100 muscles, tendons and ligaments and a network of blood vessels, nerves, skin and soft tissue. All these components work together to provide the body with support, balance, and mobility. A structural flaw or malfunction in any one part can result in the development of problems elsewhere in the body.

With all these components isn’t it any wonder that most people will experience pain in their feet at some point in their life.

PARTS OF THE FOOT

The foot can be dived into three main structures, the hind-foot, the mid-foot and the forefoot.

The hind-foot is contains the calcaneus (heel bone) and the talus (ankle bone). The top of the talus is connected to the two long bones of the lower leg (tibia and fibula), forming a hinge that allows the foot to move up and down. The calcaneus is the largest bone in the foot and joins with the talus to form the sub-talar joint which allows the foot to be turned in and out. The bottom of the heel bone is cushioned by a layer of fat and helps with shock absorption when walking.

The mid-foot has five tarsal bones. It forms the foot's arch shape, and serves as a shock absorber. The bones of the mid-foot are connected to the forefoot and the hind-foot by muscles and the an arch ligament known as the planter fascia.

The forefoot is composed of the five toes called phalanges and their connecting long bones known as metatarsals. Each toe (phalanx) is made up of several small bones. The big toe is known as the Hallux and has two phalanx bones. It has one joint, called the inter-phalangeal joint. The big toe articulates with the head of the first metatarsal and is called the first metatarsophalangeal joint (MTPJ for short). Underneath the first metatarsal head are two tiny, round bones called sesamoids. The other four toes each have three bones and two joints. The phalanges are connected to the metatarsals by five metatarsal phalangeal joints at the ball of the foot. The forefoot bears half the body's weight during walking.

MUSCLES, TENDONS AND LIGAMENTS

A network of muscles, tendons, and ligaments supports the bones and joints in the foot.

There are 20 muscles in the foot that give the foot its shape by holding the bones in position and expand and contract to provide movement. The main muscles of the foot are:

  • the anterior tibial, which enables the foot to move upward;
  • the posterior tibial, which supports the arch;
  • the peroneal tibial, which controls movement on the outside of the ankle;
  • the extensors, which help the ankle raise the toes to initiate the act of stepping forward; and
  • the flexors, which help stabilize the toes against the ground.

There are tendons in the foot that connect the muscles to the bones and joints. The largest and strongest tendon of the foot is the Achilles tendon, which extends from the calf muscle to the heel. Its strength and joint function facilitate running, jumping, walking up stairs, and raising the body onto the toes. Ligaments hold the tendons in place and stabilize the joints. The longest of these, the plantar fascia, forms the arch on the sole of the foot from the heel to the toes. By stretching and contracting, it allows the arch to curve or flatten, providing balance and giving the foot strength to initiate the act of walking. Medial ligaments on the inside and lateral ligaments on outside of the foot provide stability and enable the foot to move up and down. Skin, blood vessels, and nerves give the foot its shape and durability, provide cell regeneration and essential muscular nourishment, and control its varied movements.