Extensor Digitorum Communis
The extensor digitorum communis is a superficial extensor muscle located in the posterior compartment of the forearm.  It shares a common synovial tendon sheaths along with other extensor muscles which helps to reduce friction between the tendon and the surrounding structures. As it courses the dorsum of the hand, the extensor digitorum communis muscle spreads out into four (4) flat tendons deep to the extensor retinaculum to the medial four fingers.
Lateral epicondyle of the humerus at the common extensor tendon.
Inserts into the extensor expansion of the medial four digits.
Deep branch of radial nerve
The extensor digitorum communis is supplied by the posterior interosseous artery and the radial recurrent artery.
The extensor digitorum communis has been found to play a role in the pathology of lateral epicondylitis because of its role in the extension of the middle finger which reproduces pain on resisted extension. It has been suggested that pathology in the extensor digitorum communis may be the basis of a positive Maudsley's test.
See Extensor Tendon Injuries of the Hand for more information on injury to the extensor digitorum communis tendon.
- Moore, KL, Dalley, AF, Agur, AM. Clinically oriented anatomy. 7th ed. Baltimore, MD: Lippincott Williams & Wilkins, 2014
- Extensor Digitorum Communis - Everything You Need To Know - Dr. Nabil Ebraheim. Available from: https://www.youtube.com/watch?v=aylgUWAuYBk [last accessed 02/10/2020]
- Fairbank SM, Corlett RJ. The role of the extensor digitorum communis muscle in lateral epicondylitis. J Hand Surg Br. 2002 Oct;27(5):405-9. doi: 10.1054/jhsb.2002.0761. PMID: 12367535.
- Manual Muscle Test for Extensor Digitorum Communis. Available from https://www.youtube.com/watch?v=Qs7h8Lk1aKg [last accessed 20/10/2020]
- Physio Tutors- Maudsley's Lateral Epicondylitis Test⎟Lateral Epicondylitis or Tennis Elbow. Available from https://www.youtube.com/watch?v=BaxgmHT_2eQ [last accessed 20/10/2020]