Extensor Digitorum: Learn Your Muscles

The muscle name extensor digitorum would lead you to believe that this muscle extends the fingers. That is exactly what it does. Here’s more about the muscle that is so important to the overall health of your hand.


The origin of the extensor digitorum is on the extensor tendon from the lateral epicondyle of the humerus. As you may remember, the humerus is your upper arm bone; and the lateral epicondyle is the bony nub at the bottom of your humerus that is further away from the midline of your body.

extensor digitorum

Thanks to the Wellness Digest for the image.

The insertion of the extensor digitorum is a little bit complex because it ends up dividing into four parts to insert on each finger. It inserts on each finger via a tendon. This tendon divides into three pieces. The middle piece attaches to the dorsal surface of your middle finger bone, and the other two pieces unite to attach to the dorsal surface of the bone in the tip of your finger. Remember that the “dorsal surface” is the back of your hand.


The extensor digitorum extends your finger at the main knuckle joint and at the base of the finger. It also helps extend bones in your hand and wrist, although this movement is less noticeable. Remember, when you extend you fingers, you reach them toward the back of your hand.

Common Dysfunction

Your extensor digitorum might be dysfunctional if you are unable to extend your fingers. When you activate this muscle, your fingers should hinge toward the back of your hand. They may not move a huge amount, however, they should move some. If they don’t move, the muscle is dysfunctional. Also, if you experience pain when performing this action, you could have issues with this muscle.

Restoring or Maintaining Health

If you believe you have injured or torn your extensor digitorum, you should contact your doctor immediately. Your doctor can order all of the appropriate imaging, therapy, and medicine to help you recover as quickly as possible.

However, if you’re looking for ideas to keep these muscles healthy, I have some suggestions. As always, I recommend that you practice the function of the muscle to strengthen it. Then, perform the opposite movement to stretch it.

For the extensor digitorum, this means that you would practice reachching your fingers toward the back of your hand to strengthen this muscle. To stretch it, practice curling your fingers toward your palm. You might also stretch this muscle by rolling the palm of your hand on a tennis or lacrosse ball. (Remember, the extensor digitorum also extends bones in the hand and wrist.)

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 extensor digitorum? 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.