Peroneals: Learn Your Muscles

There are three peroneal muscles that run along the outside of your shin and cross the ankle. From the top of your shin to your ankle, they are peroneus longus, peroneus brevis, peroneus tertius. All three muscles work to lift the outside edges of your feet.

If you are someone who wears a pattern into the arch of your shoe before any of the rest, you may want to study up on this muscle.

Location

peroneals
Thanks to askthetrainer.com for the image.

The origin of the peroneus longus is on the upper lateral surface of the fibula. This means that the muscle starts on the outside edge, near the top of the outer bone in your shin. The bulk of the muscle takes up the upper two-thirds of your fibula. It inserts at the base of the first metatarsal.

The peroneus brevis originates on the lower two-thirds of the lateral surface of the fibula. So, if you have already imagined dividing your fibula into thirds, you’re a step ahead. If you haven’t imagined that yet, do so now. The peroneus longus starts at the top and runs for the top two-thirds. The peroneus brevis starts about one-third of the way down the fibula and runs for the other two-thirds. It inserts at the base of the fifth metatarsal.

Peroneus tertius originates on the lowest one-third, anterior surface of the fibula. This is different from the other peroneal muscles, which originate on the lateral surface. It inserts at the base of the fifth metatarsal.

Function

The peroneals evert the foot. This means that all three muscles help the outside edge of your foot raise so that you’re heavy on your arches.

In addition to this, the peroneus longus and brevis provide lateral stability to the ankle. They are, in fact, significant stabilizers for the outside of your ankle. Also, they assist in plantar flexion of the ankle joint. In other words, they help you point your foot.

Unlike the other two peroneals, peroneus tertius dorsiflexes the foot at the ankle. This means that it helps you flex your foot, bringing your toes toward your shin. It’s interesting that two muscles in a group would perform one action and the third muscle would perform the exact opposite.

An example of using the peroneals is walking on uneven surfaces.

Common Dysfunction

Normally, peroneal dysfunction shows up when you analyze your walking and standing posture. Check out an old flip flop and you’ll know if you tend to put your weight to the inside of your foot, outside of your foot, or right down the middle. If your weight is on the inside of your foot, your peroneals might be tight or weak. This will impact your comfort when walking or simply standing still.

As with all muscles, the peroneals can be injured.  Forced inversion of the ankle can overstretch the peroneals by forcefully rolling to the outside of the foot. This may create chronic problems with ankle joint stability in the future.

Restoring or Maintaining Health

As with all muscles, the peroneals are capable of tears or sprains. If you feel pain, it is best to consult your physician. Your medical professional can order the appropriate imaging, therapy, and medication to help you heal as quickly as possible.

If you’re wanting to strengthen your peroneals yourself, practice gently rolling to the outside edge of your feet and coming back to neutral. Then, roll in toward your arches and come back to neutral. Go back and forth between the two extremes, challenging yourself to stop at a perfectly centered neutral each time.

More Information

I consulted The Concise Book of Muscles by Chris Jarmey. Recently, the book was revised and is in its third edition. For some reason, the Amazon link wouldn’t pull up, but I did find the newest edition of the book on Amazon.

Also, I consulted my Flash Anatomy Muscles Flash Cards. If you really enjoy anatomy and want a tool to help you locate specific muscles correctly, I highly recommend these flash cards. I turn to them any time a client comes in with pain.

Here’s a link to buy them on Amazon. If you purchase them from this link, I earn a small commission.

Peroneals are tricky muscles to stretch. What do you do to stretch your peroneals? Let us know in the comments below.

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Sarah Stockett is STOTT certified in Matwork, Reformer, Cadillac, Chair, & Barrels, Injuries & Special Populations, and CORE; a Yoga Alliance RYT-200; and has studied Active Isolated Stretching. When she is not trying to discover the best exercises to get rid of pain, she likes watching movies and travelling with her family.

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