Anatomy of the peroneus longus


The peroneus longus is the main motor and stabilizer of the ankle joint. The muscle, along with the peroneal tertiary and peroneal muscles, runs along the lateral side of the lower leg and attaches to the foot.

It is used to move the foot and ankle in different directions. Peroneus longus injury can cause pain, decreased mobility, and difficulty performing basic functional tasks such as walking and running. The peroneus longus is also known as the peroneus longus. / Getty images


The peroneus longus originates from the head of the fibula and the upper half of the fibular shaft on the outside of the tibia.

It then travels down the side of the leg with the peroneal and tertiary muscles, transforms into a tendon, and joins the bottom of the foot at the medial sphenoid bone and the first metatarsal bone.

The muscle is considered the outer muscle of the ankle; originates from your leg and attaches to your foot and serves to move your ankle.

The tendons of the peroneus longus muscle are held in place near the side of the ankle by the superior peroneal retainer, a thick strip of tissue.

The peroneus longus is a superficial muscle that is easy to see and palpate . When you rotate your ankle into eversion (turning your ankle outward), you can see the muscle contraction near your calf.

The supply of nerves to the peroneus longus is through the superficial peroneal nerve that extends from the fifth lumbar level and the first and second sacral levels. Blood supply comes from the anterior tibial and peroneal arteries.

Interesting fact

The official name of the muscle was changed from peroneal to peroneal, so as not to confuse it with another anatomical structure: the perianal region .

You can imagine the confusion that could arise if your healthcare provider is instructed to examine your peroneal muscles and eventually examine your perianal area. Unfortunately, over time, anatomical names slowly change and traditional fibula names continue to be used.


The peroneus longus muscle runs along the lateral side of the lower leg and attaches to the lateral surface of the foot and the sole of the foot.

When it contracts, it twists the ankle into an eversion. This is the movement in which the ankle is pulled to the side towards the smallest toe.

The muscle also assists the calf muscle (gastrocnemius) in plantar flexion of the foot, for example by dropping the toes.

The peroneus longus muscle also supports the transverse arch of the foot. When standing on one leg, this muscle helps stabilize the lower leg at the ankle, maintaining balance.

The peroneus longus is a strong muscle and the associated tendon can withstand the high loads that can occur when walking and running.

Due to its high tensile strength, it is sometimes used during knee surgery as an anterior cruciate ligament graft. Research shows that it can be removed from the lower leg and used as a knee ligament without causing significant loss of function in the foot and ankle .

Related conditions

Injury to the peroneus longus muscle can cause pain in the lower leg, ankle, or foot. Various conditions can affect the muscle and make walking or running difficult .

Peroneal tendonitis

Peroneal tendonitis occurs when the long tendon of the peroneal muscle becomes inflamed and irritated.

This can happen due to overuse or pinching of the peroneal tendon under the bone that runs underneath. Pain on the outside of the foot and ankle can make it difficult to walk or run normally.

Stretch the peroneus longus muscles.

If there is a sudden movement of the foot or ankle, the peroneal muscles may be over-extended, resulting in a sprain.

Strains can range in severity from mild overstress to complete rupture of the peroneal muscle. Deformation of the peroneus longus can lead to:

  • Side leg pain
  • Swelling near the ankle
  • Difficulty walking and running.

Peroneal tendon subluxation

If your foot is forced to dorsiflex or invert, the peroneal tendons can be overstretched and the retention layer that holds them in place can be damaged.

This can lead to a subluxation of the tendons; the peroneus longus tendon moves past the lateral malleolus and then slides into place. It may or may not be accompanied by pain or discomfort.

Ankle ligament sprain

The most common movement of an ankle sprain is a sudden inversion of the foot and a twisting of the ankle to the side.

This can damage the lateral ankle ligaments and overstretch the peroneal tendons. As a result, irritation of the peroneus longus can occur.

Spinal nerve impingement weakness

The nerve supplying the peroneus longus leaves the lower back, and an arthritic problem or a herniated disc can cause a pinched nerve.

This can lead to lower leg pain and weakness of the muscles that move the ankle. Sometimes this can result in weakening of the tibialis anterior muscle, resulting in lowering of the foot and difficulty in normal ankle movement.

If you have shin pain, see your doctor for an accurate diagnosis and proper treatment.


If you have a peroneus longus injury, it may help to work with a healthcare professional, such as a physical therapist , to help you make a full recovery. There are several treatment options for peroneus longus injury.


Rest can be beneficial if the peroneus longus tendon heals properly. Rest can vary from three days to several weeks, depending on the severity of the injury.

If a muscle or tendon breaks, you may need to secure your ankle with a cast or removable athletic boot.

Heat or ice

If you have an acute peroneal tendon injury, it may be helpful to apply ice to the affected area to control inflammation. Ice should be applied for 10-15 minutes several times a day.

A few days after the injury , heat can be used to improve circulation. Heating can be applied for 10 minutes.

Care must be taken when using ice or heat to avoid skin irritation and burns. Your personal computer can show you the best way to apply heat or ice.

Neuromuscular electrical stimulation (NMES)

If you have peroneus longus muscle weakness due to injury or a pinched nerve, your PC can use neuromuscular electrical stimulation (NMES) to ensure proper muscle contraction and function.

NMES artificially contracts muscles to help them function properly.

Lower back exercises

If a pinched nerve is causing weakness or pain in the peroneus longus muscle, doing lower back stretches can help relieve pressure on the nerve.

Sit-ups, side slides, or low back flexion can help with a pinched nerve. Your PT can help you decide which exercises are best for you.

Stretching exercises

After a peroneus longus injury, your doctor may prescribe stretching exercises for your ankle and lower leg.

The runner's stretch can be used to stretch the calf and soleus muscles, and ankle alphabet exercises while drawing letters with the ankle can help improve ankle range of motion.

The peroneus longus muscles are stretched when the ankle is turned inward. Turn your foot inward with your hands so that the sole faces inward. Hold the stretched position for 15 seconds and then rest. This can be repeated three to five times.

Strengthening exercises

If you have a weak peroneus longus muscle, strengthening exercises can be done. To do this, simply move your foot outward in eversion. Hold this position for 5 seconds and then rest. Repeat 10-15 times.

You can also use an elastic band to strengthen the peroneus longus muscle.

First, tie the rubber band to a sturdy object, such as a sofa leg. Then put your foot in the loop, turn your ankle outward, stretching the tape, using only your foot. Hold for two to three seconds and then rest. Repeat 10-15 times.

Since the peroneus longus also serves to point to the toes, raising the calves can also help strengthen the muscles.

Just stand with your toe pads on the edge of the steps and stand on your toes. Hold this position for a few seconds and then lower yourself slowly. Do 10 to 15 repetitions.

Balance exercises and proprioception

Since the peroneus longus muscle helps stabilize the ankle and foot when walking, it can be helpful to work on improving balance and proprioception as part of a peroneal muscle rehabilitation program.

A simple one-legged advance may be prescribed.

Start by grabbing something stable and standing on one leg. If you can hold it for 30 seconds, do the exercise without holding it.

When easy, do the exercise by holding something steady, but keep your eyes closed as you balance.

Finally, stand on one leg without the support of your upper limbs and keep your eyes closed. To make the exercise with one leg more difficult, stand on something unstable, such as a sofa cushion or pillow.


After a peroneal longus injury or tendonitis, massage can improve circulation and reduce muscle pain.

Massage can also help improve muscle mobility and can be used before stretching .

Massaging the peroneal muscles should not cause pain; Gentle movements of progressive intensity are sufficient to improve movement and circulation in the peroneus longus muscle.

Orthopedic insoles or shoe inserts

Sometimes misalignment of the foot can put undue stress on the peroneus longus, resulting in pain and difficulty walking.

Your healthcare professional may recommend wearing shoe liners to help support the arch of your foot. This can help the peroneus longus muscle keep the leg in the correct position and reduce pain.


If you have persistent peroneus longus pain due to inflammation, a steroid injection may help. A steroid is a powerful anti-inflammatory agent that can reduce pain and swelling in the tendons.

A new procedure called platelet-rich plasma (PRP) injection may also be helpful in relieving pain in the peroneal muscle.

During PRP, blood is drawn from your body and spun in a centrifuge to obtain platelets and plasma. The platelets are then mixed with a small amount of plasma and injected into the tendon.

This signals your body's immune system to release white blood cells and growth factors to begin healing the damaged tendon. PRP injections are touted to help your body heal itself .

Research is ongoing on PRP therapy and its effectiveness in treating tendon injuries.


If you have a ruptured peroneus longus muscle or tendon, surgery can help repair damaged tissue and restore normal muscle function.

The operation involves an incision in the side of the leg and sutures to join the damaged muscle and tendon tissue. After surgery, you should expect to be immobilized for several weeks while everything improves.

After a period of immobilization, gentle range of motion, stretching, and strengthening can begin to restore full mobility of the peroneus longus muscle.

See your doctor if you suspect a lower leg or peroneus longus injury. If you are doing any exercises for the peroneus longus, you should consult with a specialist before starting. Stop exercising if you feel more pain.

Get the word of drug information

The peroneus longus is an important calf muscle that serves to twist and flex the ankle. Muscle injuries can cause pain and limit your ability to walk or run.

Understanding the function and anatomy of the peroneus longus can help you make better treatment decisions if you are injured or injured there.

Frequently asked questions

  • If you follow your treatment plan, you will be able to change the weight of your leg six weeks after surgery, but several more weeks of therapy and proper care will be needed for a full recovery.

  • Your foot and ankle surgeon must evaluate your injuries. They will examine the foot and assess any pain, swelling, or weakness on the outside of the ankle. You may need an X-ray or other type of imaging scan. Your healthcare provider will also rule out other possible causes of pain. Get the correct diagnosis as soon as possible to avoid major or long-term injury.

  • Ankle pain, swelling, and weakness can be caused by several types of injuries, including:

    • Tendon tears, often as a result of sports or physical activity.
    • Tendinosis, a chronic condition caused by overuse and non-healing tears.
    • Tendinitis, an inflammation in which the area becomes hot, red, and painful.
    • Tendinopathy, when tendon rupture and tendonitis are present at the same time.

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