Foot Muscles And Arches: Your Foundation In Yoga Postures

May 21, 2024
Foot Muscles And Arches: Your Foundation In Yoga Postures

Those wonderful glorious feet are, unfortunately, kept in containers (shoes) most of the day. The poor things have quite a responsibility in both our everyday walking/living life, and particularly in our yoga practice. The foot foundation, the arches of our foot, is useful in both. As a therapist, the feet are one of the first things I look at as it’s important to see what someone is standing on all day. As a yoga teacher, I’ve learned to look at the foundation first, which is the feet in standing postures. In this article, let’s take a walk through some foot muscle anatomy and see how we apply it in yoga poses.

Foot anatomy

Bones of the foot

The foot is made up of 26 bones, many ligaments, intrinsic foot muscles, and extrinsic muscles which all inter-relate with one another to create our stable, but also adaptable foot structure: arches.

The bones in the foot include:

  • Two phalangeal bones in the big toe
  • Three phalangeal bones in each of the four other toes
  • Five metatarsal bones
  • Three cuneiform bones
  • Cuboid
  • Navicular
  • Calcaneus
  • Talus

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Intrinsic foot muscles

We have two kinds of muscles that attach onto our feet, intrinsic and extrinsic. Our intrinsic foot muscles have both of their attachments somewhere on the foot. The intrinsic foot muscles make up our foot’s “core,” in the same way that deep layers of myofascia in our pelvis, torso, and other areas of our body are considered the core. Let’s take a look at how the intrinsic foot muscles are arranged.

Two intrinsic foot muscles are on the top (dorsal) side of our foot:

  • Extensor digitorum brevis
  • Dorsal interossei

The rest of our intrinsic foot muscles are located in several layers on the bottom (plantar) side of our foot:

  • Most superficially (just under the plantar fascia)
    • Abductor hallucis
    • Flexor digitorum brevis
    • Abductor digiti minimi
  • One layer deeper
    • Quadratus plantae
    • Four lumbrical muscles
  • Next deeper layer
    • Flexor digiti minimi
    • Adductor hallucis (oblique and transverse heads)
    • Flexor hallucis brevis
  • Deepest layer
    • Plantar interossei

Based on how many muscles there are on the bottom of the foot compared to how many intrinsic muscles there are on the top of the foot, you can imagine that how the foot mediates our experience with the ground is an important part of its job. Intrinsic foot muscles are involved in shock absorption and releasing elastic energy, stabilizing the foot in response to a wide variety of terrain, and providing some proprioceptive information. Some research suggests that walking/moving with bare feet increases our engagement of these important intrinsic foot muscles. So our yoga practice, assuming that we practice barefoot, could be helping us maintain healthy function in our feet!

Extrinsic foot muscles

In addition to all those small muscles within our feet, we also have extrinsic foot muscles. These are muscles that attach proximally somewhere on the lower leg and attach distally somewhere on the foot. These are muscles that you’re probably more familiar with.

The extrinsic foot muscles include:

  • Tibialis anterior
  • Fibularis longus
  • Fibularis brevis
  • Fibularis tertius
  • Tibialis posterior
  • Extensor digitorum longus
  • Flexor digitorum longus
  • Flexor hallucis longus
  • Gastrocnemius
  • Soleus

foot arches and anatomy

Arches of the foot

Why so many bones and muscles in such a small area? Don’t you find it helpful that our foot can adapt to a myriad of surfaces and terrains such as rocky roads, and a forest walk including sticks, twigs, and holes in the ground? Our foot can mold to the ground because of the interaction of our bones, ligaments, and foot muscles which create the structure of our arches. The arch structure in our feet is unique to humans. It’s part of what makes bipedalism, or walking and running on two feet for significant distances, possible.

The three arches of the foot

Most anatomists describe the foot as having three arches. We have a medial longitudinal arch that goes from the heel to the ball of the big toe. On the lateral side of our foot, we have a lateral longitudinal arch that goes from our heel to the ball of our little toe. We also have a transverse arch. Some anatomists like to get even more specific. They refer to a distal and proximal section of the transverse arch. The proximal section of the transverse arch would be the area of the arch at the tarsal bones. The distal area of the transverse arch would be the area at the ball of the foot.

Essentially we’re standing on a triangle with one point at the base of the big toe, one at the base of the little toe, and one at our heel. Connect these three points together and you get a triangle. Take these three points and connect them to the top of the ankle joint and now we’ve created a pyramid. And that, my friends, is a very stable structure to be standing on.

Where do arches come from?

We create our arches when we are very young through our actions of standing and walking. Do you ever notice that your foot gets wider when you stand on it? This is the reason you measure your foot when standing. It’s because your foot gets slightly longer along the lines of the first two arches mentioned and wider along the third. The creation of our arches is an example of our body as a form-follows-function organism. We aren’t born with them. They form as a result of our developmental processes.

The shape of our arches is created by bone shape, ligaments, fascial connections, intrinsic muscles of the foot, and extrinsic muscles in the lower leg that attach to the foot. Each arch is formed by a unique contribution of each of these structures. For example, the plantar fascia on the bottom of our feet helps stabilize both the medial and lateral longitudinal arches.

Lateral longitudinal arch

The lateral longitudinal arch, specifically, gets significant support from the bones that make it up. The bones that create this arch include the calcaneus (our heel bone), the cuboid, and the fourth and fifth metatarsals. The shape of these bones, and the way that they are arranged, make an arch shape. The extrinsic muscles fibularis longus, fibularis brevis, and fibularis tertius muscles particularly support this arch. We get additional support from several intrinsic foot muscles as well as ligaments in creating this arch too.

Medial longitudinal arch

The bones that make up the medial longitudinal arch include the talus, the navicular, the three cuneiform bones, and the three medial metatarsals. The shape of these bones arranged together does not create an arch shape, so we especially need muscles and ligaments to create an arch here. Tibialis anterior, tibialis posterior, and flexor hallucis longus are key extrinsic foot muscles that help maintain this arch. And, like the lateral longitudinal arch, we have several intrinsic foot muscles and ligaments that contribute to creating this arch too.

The transverse arch

The proximal part of this arch includes the cuneiform bones which are wedge-shaped. The shape of these bones helps form this arch. However, the distal part of the transverse arch is created by the metatarsal bones whose shape doesn’t create an arch by themselves. They need muscles and ligaments to create an arch here. The extrinsic muscles fibularis longus and tibialis posterior especially help create this arch.

Your anatomical stirrup

It’s worth taking a closer look at two of the muscles I’ve mentioned and their contribution to the arches of our feet. Those two muscles are tibialis anterior and fibularis longus. They are intimately tied into the arch on the medial side. They wrap around the foot like the stirrup you would get into on a horse. In fact, they’re often referred to as the “anatomical stirrup.”

Tibialis anterior

Tibialis anterior can be palpated quite easily. Find your shin bone (tibia) and move your finger over to the outside (lateral side) of the bone. Now, lift your foot from the ankle joint and you’ll feel the muscle beneath your fingers. You can also follow the muscle down and find a very thick tendon heading to the inside of your foot, right to the medial arch.

Fibularis longus

Fibularis longus is harder to find, so I’ll just describe it. It runs down the outside of your calf behind the bump on the outside (lateral side) of your ankle. It then runs under your foot from the lateral side, and finally heads across the bottom of your foot to meet up with tibialis anterior on the medial arch.

These two muscles together are important balancers of the foot. They affect the way your medial arch is either drawn up or falling down when standing. The formation of the anatomical stirrup, created by the balance of tension between tibialis anterior and fibularis longus, helps support both the lateral longitudinal arch and the transverse arches too. However, if that balance of tension is off, it can especially negatively affect the support for the medial longitudinal arch.

Function of our foot arches

The arches of our feet have multiple important jobs. They are critical for standing, walking, and running because of how they help us adapt to the changing surface of the ground underneath us. Part of stabilization and shock absorption happens when our muscles, bones, ligaments, and associated fascia collaborate and support our responsive arches. It’s our arches that help transfer the force from below up through the ankle joints and to the rest of our body in such a way that we stay balanced. The subtalar joint at our ankle receives the force of our weight and then distributes it between the medial and lateral longitudinal arches. For all these reasons, if there is a problem with any one of these structures, the arches may fall and the structures above (i.e. shoulders, hips, ribs, etc.) don’t function as well.

Explore your foot foundation in yoga

The foot is our foundation because it meets with the ground which generally doesn’t change, particularly in our yoga practice. So we build our foundation for yoga on the ground. And, if the foundation isn’t right everything above has the potential to go awry. We find a similar principle with the foundation of a house. If you lay the foundation and it settles unevenly or one side drops significantly more than the other, will the windows upstairs close properly? Will the front door close properly?

Exploring arches of the foot in tadasana

Let’s take this idea into standing yoga postures. Stand in tadasana and become aware of where your weight is over your feet. What does your foot foundation feel like? Perhaps the weight is more in your heels or more on your toes. No need to judge where it is, just create some awareness. There are a number of ways to engage the arches and one way is to simply lift your toes. Another way that I like is pressing the base of the big toe into the ground while also pushing down with the outer back heel. The sensation is almost like your foot is getting shorter between the base of your toes and your heel. While doing this, draw the awareness up the inside of the leg all the way up to the inside of your thighs and draw it up through the psoas.

Exploring arches of the foot in warrior one

Let’s look at warrior one for a moment. You have two feet on the ground, therefore you have two arches to be aware of. In the front foot, we’re always told to have the knee over the ankle in warrior (great idea). But, let’s play for a moment with this instruction. Take your knee in slightly and carefully notice what happens to the arch in your front foot. Did you notice the arch collapsing? The back foot is a common place to find yourself with half a foot on the floor and it’s usually not the outside half. Play with the same instruction above for engaging the arch here. Press into the ball of the foot and the outer heel and watch your arches grow.

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Conclusion

Playing with engaging the arches in this way utilizes the interaction between the muscles discussed above. Take these simple instructions and apply them to your standing yoga postures. Develop a strong foot foundation and the pose will be much stronger and functional above it.

References

McKeon, P.O., J. Hertel, D. Bramble, and I. Davis. 2015. The foot core system: a new paradigm for understanding intrinsic foot muscle function. British Journal of Sports Medicine. 49:9pgs.

Myers, T. The Foot: Understanding the Arches. In: Body3 A Therapist’s Anatomy Reader. Walpole, ME.

Sakalaukaite, R. and D. Satkunskiene. 2012. The foot arch and viscoelastic properties of plantar fascia and Achilles tendon. Journal of Vibroengineering. 14(4):1751-1759.