Your Plantar Interossei Muscles (and How to Keep Them Healthy)

The plantar interossei are small muscles in your feet that help your smaller toes hug toward your second toe. Although these muscles are small, it’s important that all the muscles in the foot work as they are intended in order to achieve muscular balance and a pain-free foot. Here’s more about these small foot muscles.

Where are your plantar interossei located?

dorsal interossei and plantar interossei
Thanks to How to Relief for the image.

There are three plantar interossei. They originate at the bases of the 3rd, 4th, and 5th metatarsal bones on the medial plantar surfaces. This means that they originate on the inside, bottom surface of the metatarsal bones, which are located in the foot.

The three plantar interossei insert on the medial sides of the bottoms of the proximal phalanges of the same toes. The proximal phalanges are another name for the bottom bone in your toe, right where your toes meets your foot.

So, basically, these muscles run along the inside of your little toe, 4th toe, and middle toe from near the middle of the foot to the base of the three toes.

What do your plantar Interossei do?

The plantar interossei muscles adduct the 3rd, 4th, and 5th toes toward the 2nd toe. Remember, to adduct means to move toward the midline of the body. Since the 2nd through 5th toes are all tied together via the flexor digitorum longus, extensor digitorum longus, and some other foot muscles; it makes sense that this muscle moves toward the 2nd toe instead of the big toe.

According to the Flash Anatomy Muscles Flash Cards, the plantar interossei “flex the proximal and extend the distal phalanges.” This sentence is sort of odd to me because people normally refer to two of the bones in each toe as a proximal and distal phalange (with the proximal being the bone near the foot and the distal being the bone in the tip of your toe).

As we can see in the picture above, the plantar interossei don’t cross any other joints further up the toe. So, I’m not for sure, but I would guess that their meaning is that these muscles help flex the metatarsal (in the foot) and extend the proximal phalanges (the bones in the bottom of your toes).

What happens when your plantar interossei doesn’t work?

Plantar interossei dysfunction might show up in one of two ways. First, if the muscles are always working, your smaller three toes would hug tightly toward the 2nd toe. Second, if the muscles are not really working, you might notice space between your toes and an inability to close the space and hug your toes together.

How to Relieve Plantar Interossei Tightness and Weakness

If you believe you have injured your plantar interossei, contact your doctor. He or she can order the appropriate imaging, medicine, and therapy necessary for a full recovery.

However, if you’re interested in some suggestions for how to keep these foot muscles healthy, I have some ideas. Plain and simple, I suggest you play with your feet.

  • Roll your feet on a tennis ball or lacrosse ball, particularly near the joint where your toe joins your foot.
  • Spread your toes apart (use your fingers if you have to), then use the muscles to bring them back together. Keep your foot on a flat surface while you work.
  • To stretch the plantar interossei, work on using the muscles on the opposite side of the toe to spread them apart. Again, use you fingers if you have to.

More Information About Your Plantar Interossei

For those who are more interested in technical terminology and smaller muscles, I recommend Flash Anatomy Muscles Flash Cards. Any time a client comes to me with pain, I use these flash cards.

If you’re here today because you’re trying to relieve your foot pain, I have a present for you! Click here to download your free copy of The Secret to Immediate + Lasting Pain Relief.

About Sarah Stockett

Hi, I'm Sarah! I'm a certified Pilates and yoga instructor with a passion for pain relief. I believe you can use simple exercises to relieve your aches + pains. AND, I believe I can teach you how.