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Extensor Carpi Radialis Brevis and Extensor Carpi Radialis Longus: Learn Your Muscles

If you have wrist pain, you’ll want to learn about the extensor carpi radialis brevis and extensor carpi radialis longus. These muscles are responsible for wrist extension (which is what your wrist does when you hold Plank) and a subtle movement called radial deviation. Read below to learn more about these two muscles.

Location

extensor carpi radialis brevis

Thanks to the University of Washington Radiology for this image of the extensor carpi radialis brevis.

The origin of the extensor carpi radialis brevis is on the common extensor tendon from the lateral epicondyle of the humerus. Your humerus is your upper arm bone, and the epicondyles are the round nubs at the bottom of the bone. The bony bump that is located away from your midline is the lateral epicondyle.

Extensor carpi radialis brevis inserts on the posterior surface of the bottom of the third metacarpal. If you slide down the back of your middle finger, along the back of your hand, right near your wrist; you’ll find the insertion point for the extensor carpi radialis brevis.

extensor carpi radialis longus

Thanks to the University of Washington Radiology for this image of the extensor carpi radialis longus.

The origin of the extensor carpi radialis longus is on the lower third of the lateral supracondylar ridge with a few fibers on the lateral epicondyle of the humerus. As mentioned above, the lateral epicondyle of the humerus is the bony nub at the bottom of your upper arm bone that is away from the midline of your body. The lateral supracondylar ridge is a visible line that runs down the middle of the lower part of the humerus. So basically, the origin for the extensor carpi radialis longus is near the bottom of the humerus, just slightly lateral of center.

The insertion of the extensor carpi radialis longus is on the posterior surface of the base of the second metacarpal. If you slide down the back of your pointer finger, along the back of your hand, right near your wrist; you’ll find the insertion point for the extensor carpi radialis longus.

Function

According to the Flash Anatomy Muscles Flash Cards, the functions of both the extensor carpi radialis brevis and the extensor carpi radialis longus are “extension and radial deviation of the hand at the wrist.” Extension is when you bring the back of your hand toward your forearm. Radial deviation is when you practice side flexion of the wrist and move your thumb side of your hand closer to your radius.

Common Dysfunction

If you have pain or tenderness at the points of origin or insertion for the extensor carpi radialis brevis or extensor carpi radialis longus, the muscle that correlates with the pain might be dysfunctional. Remember, the points of origin for both are toward the bottom, outside part of your upper arm bone. Then, the points of insertion are on the back of your hand near your wrist directly in line with your middle and pointer fingers.

Also, if you have pain or difficulty bending your thumbs toward your wrists, these muscles might be dysfunctional. Keep in mind that there shouldn’t be a ton of movement this way. The radial deviation is slight, especially compared to when you move your wrist the other way for ulnar deviation.

Restoring or Maintaining Health

If you believe you have torn or injured your extensor carpi radialis brevis or extensor carpi radialis longus, contact your doctor immediately. He or she can order the appropriate imaging necessary to determine the cause of your pain. Then, they can order medicine, therapy, or any additional suggestions for you to have the best possible recovery.

If you are wanting to keep these muscles strong and healthy, I have some suggestions. These exercises aren’t very glamorous, but they can keep your wrist healthy. First, practice extending and flexing your wrist. When you extend at the wrist (like you do when you hold Plank), you strengthen these muscles. Flexing at the wrist creates a stretch.

Then, practice laterally flexing your wrist. Move your thumb toward your wrist to strengthen these muscles, and move your pinkie toward your wrist to stretch them.

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 carpi radialis brevis and/or the extensor carpi radialis longus? 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.

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