The common extensor tendon…part 17 of the grumbly muscle blog…

What does a common extensor tendon do?

It is the tendon implicated in Tennis Elbow (lateral epicondylitis) and becomes our forearm extensor muscles (then ones on the top of your forearm) which help us extend your fingers and hands at the wrist (bend back towards you).

It becomes three superficial muscles;

  • Extensor Digitorum (extends the wrist and fingers)
  • Extensor Carpi Ulnaris (adducts the wrist and little finger)
  • Extensor Carpi Radialis Brevis (extends and abducts the wrist, extends the middle finger, and helps flex the elbow)


This tendon starts on the outside of the elbow (called the lateral epicondyle) before forming into the above muscles attaching at the wrist.

Why does it get grumbly?

Tendons exist on a continuum, and they can suffer from overuse. As we age, tendons don’t regenerate as fast, so we can experience degeneration of the tendon.  Most commonly those age 35 – 55, both sexes are affected and is usually felt in the dominant arm.

Some people lack range of movement in the shoulders (usually external rotation) and the forearm muscles can overcompensate to make up for this.

Office workers, drivers, trades people and athletes that predominantly use their arms in sport (not just tennis players) can experience this, so too can manual workers, especially involving tools weighing greater than 1kg, repetitive actions and heavy lifting.

What can we do about it?

Firstly, strengthen the shoulder complex and improve range of movement though rehab, but in the meantime, soft tissue release of the muscles and dry needling of both the muscles and the tendon work very well to alleviate the pain.  If you can get them to stay on, dry cupping is also quite effective.

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