Ankle Anatomy

The ankle is a complex structure that contains three joints and several ligaments, muscles, and tendons that are extremely important for walking and running. The unique design of the ankle makes it a very stable joint. The ankle has to be stable in order to withstand 1.5 times your body weight when you walk and up to eight times your body weight when you run.

The ankle works like a hinge to allow the foot to move up (dorsiflexion) and down (plantarflexion). The anatomical structures of the ankle can be divided into the following categories:

• Ankle Bones
• Ankle Ligaments
• Ankle Tendons
• Ankle Muscles
• Ankle Nerves
• Ankle Blood Vessels

Ankle Bones

The ankle is formed by the connection of three bones. The main ankle bone is called the talus. The top of the talus fits inside a socket that is formed by the lower end of the tibia (shinbone) and the fibula (the small bone of the lower leg). The bottom of the talus sits on the heel bone, called the calcaneus.

A similar design, called mortise and tenon, is used by craftsmen and woodworkers to create stable structures. Many furniture joints and building foundations have a design that is similar to the anatomy of the human ankle.

Articular Cartilage

Inside the ankle, the bones are covered with a slick material called articular cartilage. This durable material covers the ends of the tibia, fibula, talus, and calcaneus bones. The articular cartilage lining is about one-quarter of an inch thick. This allows the ankle bones to move smoothly against one another and acts as a natural shock absorber. Articular cartilage is soft enough to allow for shock absorption, but tough enough to last a lifetime, as long as it is not injured.