The tibialis posterior is the deepest muscle on the back of your calf. It’s not glamorous like the gastrocnemius, and it’s not got an important nickname like the soleus, your “second heart.” However, the tibialis posterior plays an important role in your ability to walk, stand, and even drive your car. Dancers and other people who stand and walk with turned out feet will especially want to learn about this muscle and how to keep it healthy.
As you may notice from the picture, the tibialis posterior is a neighbor to the flexor hallucis longus and flexor digitorum longus.
The origin of the tibialis posterior is on the lateral posterior surface of the tibia, the proximal two-thirds of the medial surface of the fibula, and most of the interosseous membrane.
There is an interosseous membrane present in the forearm and in the lower leg. The interosseous membrane runs between the tibia and fibula. It stabilizes the bones and also helps serve as a division line, separating the front half of the leg from the back half. This helps make sure that muscles don’t cross the line and end up on the wrong side of the body.
According to the Flash Anatomy Muscles Flashcards, the insertion of the tibialis posterior is on the “tuberosity of the navicular bone with branches to sustentaculum tali of calcaneus, plantar surfaces of all three cuneiforms and cuboid and to bases of the second, third, and fourth metatarsals.” If you’re like me almost none of these words ring any bells.
Here’s the translation: The tibialis posterior inserts on the bottom of your foot to a bunch of little bones in the mid-foot. These bones are from about the middle of your arch back toward, but not actually including, your heel.
The main function of the tibialis posterior is to assist in plantar flexion of the ankle. This means that the muscle helps you point your foot. Being able to point your foot is crucial for activities like standing on your tip toes or pushing down the gas pedal. This movement is also crucial for a neutral walking gait.
Additionally, the tibialis posterior inverts the foot. This means that it is one of the muscles that helps lift your arches and shift your weight toward the outside edge of your foot. If you ever wonder if your feet are balanced, check your flip flops. The wear pattern will let you know if your step is heavy one direction or another.
The tibialis posterior also acts as a medial ankle stabilizer. This means that it helps keep the inside of the ankle stable and supported.
According to The Concise Book of Muscles by Chris Jarmey, “walking/standing with feet turned out will cause collapse of the medial longitudinal arch of the foot.” As someone who has spent a good deal of time correcting the odd habits that my body learned from years of dancing, this is probably the most valuable sentence I’ve ever read.
As I’ve discussed many times, the whole body is connected. When you’re troubleshooting an issue or injury, you start with obvious causes. You look at large, more superficial muscles first. If the injury persists, you look deeper. Fascia, smaller muscles, deeper muscles, neighboring muscles all get examined until you can find the cause for your issue.
That’s why it’s so good to know that if you are having issues with a collapsing arch and your feet tend to be turned out, immediately check out your tibialis posterior.
Restoring or Maintaining Health
Keep in mind that, just like all muscles, the tibialis posterior can be seriously damaged. If you are in pain, it is best to go to your doctor. Your doctor can order imaging, medicine, and therapy to correctly treat your injury.
That being said, there is not a lot of information out there about how to fix your tibialis posterior or even keep it healthy. When this is the case, I suggest that you learn about the muscle that you want to help, figure out what exactly it does, then do the opposite.
For example, the tibialis posterior:
- plantar flexes at the ankle.
- inverts the foot.
- medially stabilizes the ankle. (I have no idea how you could do the opposite of this without breaking your ankle, so let’s skip the counter-activity to this.)
Therefore, I would suggest that you dorsiflex your ankle. Almost all stretches for the gastrocnemius and soleus involve dorsiflexion, but you could simply sit and bring your toes toward your shin. It doesn’t have to be glamorous; it just has to be done correctly.
Also, try everting. You can do this by letting your weight press into your arches. I like to practice finding neutral as I move between inversion and eversion.
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 for this newest edition, but it is available on Amazon.
Also, I consulted my Flash Anatomy Muscles Flash Cards. If you enjoy anatomy and want a tool to help you locate 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.
How many people who walk or stand with turned out feet are now checking out their tibialis posterior? I know I am!