How to Prevent Ankle Sprains – Anatomy (Part 1)

One of the most common injuries of the lower extremities is an ankle sprain. While people often associate a sprained ankle with sports, all kinds of people sprain their ankles every day. It's an injury that could be caused by something as simple as walking of a curve, stepping on a rock, or missing a step. Because so many people suffer from ankle sprains there is great interest in their prevention. This series of articles will focus on the best ways to prevent ankle sprains. This information is based on decades of study and research by some of the foremost experts in sports medicine and the treatment of musculoskeletal injuries.

Before exploring ways to prevent ankle sprains it is important to discuss what an ankle sprain is and how it occurs. The ankle joint is unique because it is built to bear and stabilize the majority of the body's weight while still being relatively mobile. This seeming contradiction in requirements for stability and mobility is one reason the ankle can be injured so easily.

To understand the injury one must first understand the anatomy of the joint. There are two bones in the lower leg. The larger of the two bones is called the tibia. This bone goes from the knee joint down to the ankle and makes up the bony knob found on the inside portion of the ankle. The other bone is the fibula, which is a long skinny bone that travels with the tibia from the knee down to the ankle. The fibula, however, is the outer bone in the leg and makes up the outer bony knob of the ankle joint. If you feel your ankle right now you can feel these bones, the tibia on the inside and the fibula on the outside. Each knob is called a malleolus. The tibia and fibula are joined together near the knee joint and also just above the ankle joint. The ligament which attaches the tibia and fibula above the ankle is called the distal tibiofibular ligament.

Anatomically the ankle is classified as a complex joint because it is made up of more than two bones. The first two bones are the tibia and fibula. The third bone is irregularly shaped and called the talus. The talus fits perfectly in the space between the two malleoli (which is the word for more than one malleolus). The talus pivots in this space allows you to point your toes towards the floor or toward your nose. This is the main motion of the ankle but it also allows for a little bit of turning inward and outward.

There are ligaments that attach each malleolus to the talus so that the talus does not come loose and the joint can be stable. On the inside of the ankle there is a series of ligaments that go from the malleolus of the tibia to the talus. These ligaments together are called the deltoid ligament. On the other side of the joint the malleolus of the fibula is connected to the talus by three ligaments: the anterior talofibular ligament (on the front part of the malleolus), the calcaneofibular ligament (on the bottom part of the malleolus) and the posterior talofibular ligament (on the back part of the malleolus).

There are two more ligaments that are important to know about when learning about ankle sprains. These ligaments are bands that wrap around the entire joint called the flexor retinaculum and the extensor retinaculum. These ligaments hold the tendons that travel from the leg to the foot down close to the bones. They also help to stabilize the ankle joint.

The last piece of anatomy to consider is the muscles that control the motion of the ankle. The tendons of several muscles cross the ankle joint. Some of these muscles, like the peronei muscles located on the outer portion of the leg, function mainly to move the foot while others mainly move the toes.

Now that you have a basic understanding of the anatomy involved. The next article in this series will describe the different types and grades of ankle sprain. In addition you will learn how these injuries are caused.