So you just stepped off a curb wrong and rolled your ankle. Curious about what you may have sprained? Read on to learn how to identify what you sprained in your ankle. Make sure you rule out a fracture first here
3 Mechanisms for Ankle Injury
- Inversion – this is most likely going to be an ATF sprain. The CF and PTF ligaments are injured secondarily
- Eversion – this is going to be a deltoid ligament sprain
- External rotation – this is going to injure the syndesmosis ligament (high ankle sprain)
Inversion Ankle Sprain
An inversion ankle sprain is by far the most common ankle sprain there is (source). This is most likely to occur when you land on someone’s foot when competing in sports, however, a lot of people simply misstep off a curb. This and plantarflexion (foot points down) occur together.
With this type of injury, there is going to be trauma to three ligaments. They are listed in the order in which injury occurs. As a general rule of thumb, however, as the injury severity increases, so does the amount of total structures injured. See the image below to identify where the ligaments are located
- ATFL (anterior talofibular ligament)
- CFL (calcaneofibular ligament)
- PTFL (posterior talofibular ligament)
Eversion Ankle Sprain
This is second most common injury to have for an ankle as the mechanism is difficult to do. For you do evert your ankle and sprain it, you typically apply valgus force to your knee which in turn everts your foot. When you apply valgus force to your knee, there is concern for an MCL injury as well. If there is concern for an associated MCL injury click here
The deltoid ligament consists of 4 different ligaments. However, we will lump all four into the deltoid ligament as there is no reason to differentiate them as isolating one over another is difficult. The deltoid ligament consists of the following:
- Anterior tibiotalar ligament
- Tibiocalcaneal ligament
- Posterior tibiotalar ligament
- Tibionavicular ligament
External Rotation Ankle Sprain
This is the rarest and most difficult ankle sprain. “Ankle sprain” is a loose definition here as the sprain is more of an injury to the tibia and fibula. The syndesmosis ligament is responsible for keep the tibia and fibula together; a sprain here causes the bones to drift apart. As such, this is by far the slowest healing of all three ankle injuries. High ankle sprains recovery times are in weeks/months.
This type of injury is usually the result of a collision. When someone is hit in a collision, the foot rotates to match the direction of the force. This injury almost always occurs under high joint stress that occurs with sprinting.