Dorsal Interossei Muscles of the Hand and Foot: Learn Your Muscles

I was surprised to discover that there are some muscles in the hands and feet that are the same. This shouldn’t necessarily have been surprising because when you look at the structure of the hands and feet, they’re very similar.

Still, I guess I imagined that even the most similar muscles in the body would all have different names. Apparently, that isn’t so. Here’s more information about the first of several muscles that appear in both the hands and feet–the dorsal interossei.

Location

There are four dorsal interossei muscles on the hand. According to the Flash Anatomy Muscle Flash Cards, they originate from “the two metacarpal bones between which it inserts.” The metacarpal bones are the bones in the palm part of your hand.

dorsal interossei muscles of the hand

Thanks to the University of Washington Radiology.

These muscles insert on the “bases of the proximal phalanges of the 2nd, 3rd, and 4th digits and the extensor expansion.” The proximal phalanges are the bottoms of your fingers, near where the fingers meet the palm.

Similarly to the hand, there are four dorsal interossei muscles in the foot. As you can see in the image below, these muscles are set up really similarly to the hand muscles. The dorsal interossei muscles of the feet originate in the upper part of your foot and insert near the juncture of your four smaller toes and your foot.

dorsal interossei and plantar interossei

Thanks to How to Relief for the image.

That, of course, is my condensed version. According to the Flash Anatomy Muscle Flash Cards, the origin of the dorsal interossei of the foot is “by 2 heads from adjacent sides of the metatarsals.” Their explanation of the insertion is “bases of the proximal phalanges and extensor expansion of the tendons of the extensor digitorum longus. The 1st dorsal interosseous (arising from the 1st and 2nd metatarsals) inserts into the medial side of the 2nd toe. The 2nd-4th dorsal interossei insert into the lateral sides of the 2nd, 3rd and 4th toes.”

Function

The dorsal interossei muscles of the hand help abduct the pointer, middle, and ring fingers. This means that they help the fingers spread away from the axis that runs through the center of the middle finger.

Additionally, the Flash Anatomy Muscle Flash Cards say that these muscles help flex “the proximal phalages of the index, middle and ring fingers at the metacarphphalangeal joints” and extend “the middle and distal phalanges.”

In the foot, the dorsal interossei muscles pretty much do the same thing. The big difference is that, unlike the hand, the axis of the foot runs through the second toe not the third. Additionally, these muscles assist in “flexing the proximal phalanx and extending the middle and distal phalanges.”

Common Dysfunction

If you have pain in your hands or feet near the spot where your fingers or toes join, you might have some dorsal interossei muscle dysfunction. These muscles might also be dysfunctional if you feel like it’s painful or difficult to hug your fingers or toes toward their midline. (Remember, the midline for the fingers is the middle finger. The midline for the toes is the second toe.)

Restoring or Maintaining Health

If you feel like your dorsal interossei muscles are injured, contact your doctor. He or she can order the appropriate imaging, therapy, and medicine for recovery.

For anyone wanting to keep their hands and feet healthy, I have some suggestions.

  • Practice spreading your fingers and toes apart. Make sure your fingers and toes spread at the same speed and in the same line. Then, hug your fingers and toes toward the midline of your hand or foot.
  • Move your fingers and toes back and forth at the spot where they join the hand or foot.

Performing these simple exercises should help keep these muscles strong, healthy, and functioning correctly.

More Information

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.

Do you have any other suggestions for strengthening or stretching the dorsal interossei muscles of the hand and foot? Let us know in the comments below.

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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.