The peroneus longus is an important muscle in your lower leg. It starts at the top of the fibula before running down the outside of the leg and connecting to the foot with the peroneus longus tendon. Your peroneus longus muscles help you move your ankles, flex your feet, and maintain your balance.

What causes pain in the peroneus longus?

Peroneal tendonitis occurs when the long tendon of the peroneus muscle becomes inflamed and irritated. This may occur due to overuse, or the peroneal tendon may be pinched beneath the bone that is courses under. Pain on the outer portion of your foot and ankle may result making it difficult to walk or run normally.

What is peroneus longus tendon?

Peroneus longus and peroneus brevis are muscles that originate on the outer bone of the lower leg called the fibula. These become tendons above the ankle in order to attach the muscles to the foot.