Ankle Anatomy

The foot and ankle is a complex joint involved in movement and providing stability and balance to the body. The foot and ankle consists of 26 bones, 33 joints, and many muscles, tendons and ligaments.

Bones of the Ankle

The ankle joint connects the leg with the foot, and is composed of three bones: tibia, fibula and talus. The tibia (or shin bone) and fibula are bones of the lower leg which articulate with the talus or ankle bone, enabling up and down movement of the foot.

Three bony bumps present on the ends of the tibia and fibula form parts of the ankle joint:

  • The Medial malleolus, formed by the tibia, is found on the inside of the ankle;
  • Posterior malleolus, also formed by the tibia, is found at the back of the ankle and the
  • Lateral malleolus, formed by the fibula, is found on the outer aspect of the ankle

Ankle Joints

There are 33 joints in the ankle and foot. They include the

  • Hinge joints in the ankle, which allow flexion (bending) and extension
  • Gliding joints found in the hindfoot, which allow gliding movements
  • Condyloid joints found in the forefoot and toes, which allow the flexion (bending) and extension, adduction and abduction (sideward movement).

The joints of the foot and ankle provide stability and support the weight of the body, helping you to walk or run, and to adapt to uneven ground.

The joint surface of all bones of the ankle and foot are lined by a thin, tough, flexible, and slippery surface called articular cartilage, which acts as a shock absorber and cushion to reduce friction between the bones. The cartilage is lubricated by synovial fluid, which further enables smooth movement of the bones.

Soft Tissues of the Ankle and Foot

Our foot and ankle bones are held in place and supported by various soft tissues such as cartilage, ligaments, muscles, tendons and bursae.

Cartilage is the flexible, shiny, smooth tissue on the ends of bones that meet to form a joint. Cartilage provides cushioning between the bones allowing smooth movement.

Ligaments are tough rope-like tissue that connect bones to other bones, and holds them in place providing stability to the joints. The Plantar fascia is the largest ligament in the foot, originating from the heel bone to the forefoot, it extends along the bottom surface of the foot and is involved in maintaining the arch of the foot. The plantar fascia ligament stretches and contracts to provide balance and strength to the foot. Lateral ligaments on the outside of the foot and medial ligaments on the inside of the foot provide stability and allow up and down movement of the foot.