Dislocating peroneal tendons are an uncommon injury to a group of two tendons whose muscles originate on the outside of the calves. These two muscles are named the Peroneus Brevis and Peroneus Longus. These two muscles are responsible for eversion of the foot. This movement of the foot is demonstrated by standing and then rolling to the outside of the foot. These tendons are commonly referred to as “stirrup” tendons because as they pass into the foot they act as a stirrup to help hold up the arch of the foot. As these tendons pass behind the outside ankle bone, called the fibula, they are held in place by a band of tissue called the peroneal retinaculum. Injury to the retinaculum can cause it to stretch or even tear. When this occurs the peroneal tendons can dislocate from their groove on the back of the fibula. The tendons can be seen to roll over the outside of the fibula. This will cause the tendons to function abnormally and can cause damage to the tendons. Dislocating peroneal tendons most commonly occur as a result of injury during participation in athletic activities. The most common sport causing injury is snow skiing. This injury can also happen while playing football, basketball, and soccer. This injury can occur in non-athletes, as a result of a severe ankle sprain. The injury typically results in a popping or sharp pain on the outside of the ankle; however, there may be little to no discomfort at the time of injury, which later becomes symptomatic.