Extensor digitorum muscle

Last revised by Henry Knipe on 8 Feb 2023

Citation, DOI, disclosures and article data

Citation:

Mirt G, Knipe H, Hacking C, et al. Extensor digitorum muscle. Reference article, Radiopaedia.org (Accessed on 28 Nov 2023) https://doi.org/10.53347/rID-41591

DOI:

https://doi.org/10.53347/rID-41591

Permalink:

https://radiopaedia.org/articles/41591

rID:

41591

Article created:

9 Dec 2015, Greg Mirt

Disclosures:

At the time the article was created Greg Mirt had no recorded disclosures.

View Greg Mirt's current disclosures

Last revised:

8 Feb 2023, Henry Knipe ◉ ◈

Disclosures:

At the time the article was last revised Henry Knipe had the following disclosures:

Integral Diagnostics, Shareholder (ongoing)
Micro-X Ltd, Shareholder (ongoing)

These were assessed during peer review and were determined to not be relevant to the changes that were made.

View Henry Knipe's current disclosures

Revisions:

15 times, by 10 contributors - see full revision history and disclosures

Systems:

Musculoskeletal

Sections:

Anatomy

Synonyms:

Extensor digitorum communis
Extensor communis
Extensor digitorum muscle
Extensor digitorum communis muscle
Extensor digitorum muscles
Extensor digitorum communis muscles

Extensor digitorum (ED) muscle, also known as extensor digitorum communis (EDC) muscle, is a muscle of the superficial layer of the posterior compartment of the forearm and with other extensor muscles arises from a common tendon attached to the lateral epicondyle of the humerus. It is one of the extrinsic muscles of the hand.

Summary

origin: lateral epicondyle of humerus
insertion: middle, distal phalanges on dorsal surface; extensor expansions of digits 2-5
arterial supply: radial recurrent artery, posterior interosseous artery
innervation: posterior interosseous nerve (C7, C8), a continuation of the deep branch of the radial nerve (C7, C8)
action: extension in metacarpophalangeal joint

Gross anatomy

ED represents a medial group of superficial extensor muscles. ED passes under the extensor retinaculum which holds it tight and passes through the 4^th extensor compartment of the wrist, once it passes under the sagittal band of the metacarpophalangeal joint the tendon splits into three 'slips' consisting of two lateral slips and a central slip ^1-3.

The central slip inserts at the dorsal surface of the base of the middle phalanx ^1-3.

The lateral slips, run both sides of the proximal interphalangeal joints to then converge with the lumbrical and interosseous fibers to form conjoint tendons, that converge over the middle phalanx and insert at the dorsal aspect of the base of the distal phalanx as a single terminal tendon ^1-3.