Foot & Ankle Anatomy

The foot combines mechanical complexity and structural strength. It supports and balances our body’s weight while standing, as well as raising and moving the body in a forward and backward Footmotion when walking. The ankle serves as foundation, shock absorber, and propulsion engine.

The ankle is a hinge-type, freely moving joint that consists of a capsule containing fluid which both nourishes and lubricates the joint making motion possible between the foot and the leg.

The foot and ankle contain:

  • 26 small bones (one-quarter of the bones in the human body).
  • 33 joints.
  • more than 100 muscles, tendons and ligaments.
  • a network of blood vessels, nerves, skin, and soft tissue.

These components work together to provide the body with support, balance, and mobility.

Parts of the Foot

Structurally, the foot has three main parts: the forefoot, midfoot, and hindfoot.

The forefoot is composed of the five toes (called phalanges) and their connecting long bones (metatarsals). Each toe is made up of several small bones. The big toe has two phalanges, two joints and two tiny, round sesamoid bones that enable it to move up and down. 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 midfoot has five irregularly shaped tarsal bones, forms the foot’s arch, and serves as a shock absorber. The bones of the midfoot are connected to the forefoot and the hindfoot by muscles and the plantar fascia ligament.

The hindfoot is composed of three joints and links the midfoot to the ankle. The top of the talus is connected to the two long bones of the lower leg forming a hinge that allows the foot to move up and down. The heel bone is the largest bone in the foot. It joins the talus to form the subtalar joint, which enables the foot to rotate at the ankle.

ankleMuscles, 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 impart movement. The main muscles of the foot are:

  • the anterior tibia, which enables the foot to move upward.
  • the posterior tibia, which supports the arch.
  • the peroneal tendon, 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.
  • the flexors, which help stabilize the toes against the ground.

Parts of the Ankle

The ankle joint consists of the connection of the talus and the lower ends of the two leg bones (tibia and fibula). Multiple ligaments provide stability to the ankle joint.

The chief motions of the ankle are flexion and extension. Like synovial joints (those joints in which fluid is present) the ankle is subject to many diseases and injuries.

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