The finger extensor
Extensor digitorum · musculus extensor digitorum
The forearm muscle that straightens your four fingers.
What it does
The extensor digitorum runs from the outer elbow down the back of the forearm and splits into four tendons, one for each finger. It straightens the fingers and helps lift the wrist. You can see its tendons stand out on the back of your hand when you spread your fingers.
Surprising fact
Its tendons are linked by bands across the back of the hand, which is why it is hard to lift your ring finger on its own while the others are curled down.
Why it matters
Overusing the wrist and finger extensors, for example with a mouse or a racket, is one of the causes of tennis elbow pain on the outer side of the joint.
Nearby
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Sources
Drafted with AI help; awaiting a human fact-check against these sources.
Open in the 3D atlas · Suggest a correction · Not medical advice.
3D models: Z-Anatomy & BodyParts3D (CC BY-SA 4.0 / 2.1 JP). Card text CC BY 4.0.