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Workshop/4 min exploration

The remarkable human ankle

Why can your foot point down and also tilt sideways?

What we casually call the ankle is a team of joints. The joint above the talus mainly lets the foot point up and down. Below it, the subtalar joint helps the foot tilt. Explore the two movements separately.

3D model

Explore the model and follow its moving parts.

Read the full explanation ↓
Drag to rotate · Scroll to zoom · Select a part

Different joints share the movement. Tendons transmit muscle force; ligaments help guide and stabilise.

Which structure carries the calf muscles’ pull to the heel?

Follow the explanation

Back to the model ↑

How the parts work together

  1. Lift and point

    Move the flexion slider. Bringing the top of the foot toward the shin is dorsiflexion; pointing it away is plantar flexion.

  2. Tilt the sole

    Move the tilt slider. Inversion turns the sole inward; eversion turns it outward. The subtalar and other foot joints contribute.

  3. Look at the connections

    Show the soft tissues. Tendons connect muscle to bone; ligaments connect bones. Their routes help explain their different jobs.

The main parts

Tibia · shinbone
The larger lower-leg bone. Together with the fibula, it holds the talus in the ankle joint.
Talus · anklebone
Sits between the lower leg and heel. Its upper joint mainly permits up-and-down movement.
Calcaneus · heel bone
The bone beneath the talus. Their shared subtalar joint contributes to inward and outward tilting.
Fibula · outer leg
The slender bone beside the tibia. Its lower end forms the outer ankle prominence and helps contain the talus.
Navicular
Sits in front of the talus on the inner side of the foot, contributing to the arch.
Cuboid & cuneiforms
Four small bones between the rear foot and metatarsals. Their shape helps organise the arch and the bases of the toes.
Metatarsals
Five long bones connect the midfoot to the toes. Compare the strong first metatarsal with its neighbours.
Toe bones
The big toe has two phalanges; each other toe has three. These fourteen bones are shown as reference surfaces.
Achilles tendon
Connects calf muscles to the heel bone. It transmits the muscle pull used to point the foot down and rise onto the toes.
Supporting ligaments
Bands connecting bone to bone. They help stabilise the joints and limit excessive movement.

One discovery leads to another.

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