💪 Extensor Digitorum

Brian Lee
Aug 27, 2025
Reviewed
Table of Contents

Summary

Origins
Lateral epicondyle of the 🦴 humerus
Insertions
Extensor expansions of digits two through five
Actions
Extends digits two through five
Assists wrist extension

The extensor digitorum lies in the posterior forearm and sends four thin tendons to the back of the hand. Each tendon crosses the dorsal wrist and inserts into the extensor expansions of digits two through five, allowing them to straighten at the metacarpophalangeal joints.

It shares a common origin at the lateral epicondyle with 💪 extensor carpi ulnaris and 💪 extensor digiti minimi. The muscle is an antagonist to the flexor digitorum superficialis.

References