The center of the ankle is the bone called the talus. The talus bone has a large cartilage covering which allows the ankle to glide effortlessly across the cartilage of the large leg bone called the tibia. When these two bones meet they form the ankle joint. On the outside of the ankle is a smaller, thinner bone called the fibula. This bone helps prevent the tibia from shifting outward.
The stability of the ankle joint is dependent upon the ability of these bones to keep the central talus bone in place while the ankle moves back and forth. The joint is more stable when the foot is flat on the floor. However, when the toes are pointed down, the ankle becomes unstable because the distance between the bony stabilizers of the ankle becomes larger. Thus, the ankle relies more and more on the ligaments to provide stability. Since the ligaments are “softer” than bones, the ankle becomes more vulnerable to a sprain when the toes are pointed.
When an ankle twists, it is usually when the toes are pointed down. However, the ankle can be twisted while in any position. There are six major soft tissue structures that hold the ankle in place. Four of these are located on the outside part of the ankle and all attach to the fibula. Thus, all four of these ligaments have the word fibula in them. The most commonly injured ligament of the ankle is called the Anterior (meaning front) Talo-Fibular Ligament, or ATFL for short. This is the ligament that is most commonly torn in ankle sprains. The second most commonly torn ligament is the ligament connecting the heel bone to the fibula called the Calcaneo-Fibular Ligament. The third ligament again attaches the fibula to the back of talus called the Posterior (meaning back) Talo-Fibular Ligament. The fourth ligament connected to the fibula is the Tibiofibular Syndesmotic Ligament, which connects the fibula to the tibia. The soft tissue just in front of the ankle is the capsule of the ankle joint and helps keep the ankle from sliding forward along with the other ligaments. The final stabilizing ligament is on the inside part of the ankle. As this ligament forms a triangle shape like the Greek letter delta, it is called the Deltoid Ligament. The deltoid ligament attaches the inner tibia to the talus.
Sometimes the bones around the ankle can break. Most commonly it is the smaller outer bone called the fibula. However, with larger forces applied to the ankle, both the fibula and tibia can break. When the bones around the ankle break, they can cause severe instability and may even result in a dislocation of the ankle joint. In some cases, the ankle moves slightly out of joint called a subluxation. If a physician diagnoses a break or fracture, they may recommend surgery based upon the actual or potential dislocation of the ankle.
Foot and Ankle Conditions
Why Dr. Joseph Hecht?
Dr. Hecht is board certified in orthopedic surgery, providing expert knowledge and expertise in the area of foot and ankle conditions, preservation and treatment options. As one of the top Northwest Indiana and Chicagoland foot and ankle surgeons, Dr. Hecht brings years of valuable experience to every assessment.