Peroneal Tendinitis Anatomy
There are two peroneal muscles tendons in each leg – the peroneal longus and peroneal brevis.
- Peroneal longus:
- Originates at the fibular head
- Tendon goes underneath the foot and attaches to the inside of the arch on the first metatarsal and the medial cuneiform
- Peroneal Brevis:
- Originates at outside bottom two thirds of fibula
- Tendon attaches to the outside of the foot at the base of the little toe (fifth metatarsal)
Both run side by side down the outside lower leg bone (fibula) and behind the outside ankle bump called the lateral malleolus.
What Does the Peroneal Tendon Do?
- Provides stability to the ankle when it is bearing weight
- Helps protect it from sprains
- Help turn the foot out and stabilize the arch when walking
How Does Peroneal Tendinitis Happen?
- They most commonly occur in individuals who participate in sports that involve repetitive ankle motion.
- Chronic ankle sprains
- Acute ankle sprains
- A sudden increase in training/exercise
- Inadequate or unsupportive footwear
- Higher foot arches
- Poor coordination/muscle sequencing of lower limb muscles and joints
- Imbalanced muscles and/or weakness in the lower limb
Peroneal Tendinitis Symptoms
- Pain on outside of ankle
- Swelling and tenderness right behind outside ankle bone (lateral malleolus)
- Warm to the touch
- Weakness or instability of the foot and ankle
- Pain when pushing off the ball of the foot during walking or running
- Pain when walking on a sloped terrain that turns the foot outward
- Pain when stretching the foot in an inward and downward direction
- Chronic peroneal tendonosis (degenerative tears) are usually due to overuse and occur over long periods of time, often years. The tendon can be overstretched until it becomes thin and eventually frays.
- Achy pain at outside of the ankle
- Weakness or instability in the ankle
- An increase in the height of the arch
- Subluxation of peroneal tendons can also occur
As time goes on, these tears may lead to a change in the shape of the foot in which the arch may become higher.